Caterpillarengine - industrialgas engine
Caterpillar G3408
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar G3408 is a V-8, four-stroke, rich-burn natural gas engine built on Cat's G3400 industrial engine platform for stationary gas-compression and mechanical-drive duty. It is not the mobile diesel 3408 used in Cat dozers and scrapers, though it shares that engine's basic block architecture. Cat offers it naturally aspirated or turbocharged-aftercooled, rated 190-298 bkW (255-400 bhp) at 1500 or 1800 rpm depending on configuration and site conditions. Net dry weight for the base engine package is about 1,678 kg (3,700 lb.), with a footprint of roughly 1,738 mm (68.4 in.) long by 1,312 mm (51.7 in.) wide by 1,542 mm (60.7 in.) high. It typically drives wellhead gas compression, gas lift, and gas-gathering packages, along with generator sets and other continuous-duty industrial loads. The block traces back to Cat's 3400-series V-8 introduced in the 1970s, adapted for gas service; a specific factory date for when the G3408 itself entered the lineup is not documented in available sources, but the engine remains part of Caterpillar's current gas-compression engine lineup, and no confirmed discontinuation date turned up either.
Configuration drives most of the variation seen across G3408 units in the field. The 1500 rpm continuous-duty rating tops out lower than the 1800 rpm ratings, and turbocharged-aftercooled engines add altitude capability and higher output over naturally aspirated units at the cost of extra cooling and aftercooler service points. Control hardware varies too: the standard mechanical Woodward PSG governor and digital wasted-spark ignition were later joined by optional electric or pneumatic PSG and electronic speed-control governors, well short of the full ADEM electronic controls and detonation-sensitive ignition timing Cat built into the later G3408C. That gap matters in the used and parts market. G3408 units are mechanically simpler and cheaper to keep running than their electronically controlled counterparts, so a large installed base in gas-field compression service is still being rebuilt rather than replaced outright. Parts and service knowledge carry across the wider G3400 gas engine family, including the G3406 and G3412, which keeps support and used components available even as Caterpillar's newer platforms take over new-equipment sales.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar G3408 specifications
Engine
| Model / platform | Cat G3408 - V-8, four-stroke-cycle, rich-burn natural gas engine built on the G3400 industrial engine platform (shares its block architecture with the 3408 diesel). |
| Power rating (1800 rpm) | 190-317 bkW (255-425 bhp) at 1800 rpm, depending on the specific rating selected and site derate (altitude, ambient, fuel). |
| Power rating (1500 rpm) | Up to 249 bkW (332 bhp) at 1500 rpm. |
| Displacement | 18.0 L (1099 in3) |
| Bore x stroke | 137 mm x 152 mm (5.4 in x 6.0 in) |
| Cylinders / configuration | 8 cylinders, V-configuration, water-cooled |
| Aspiration | Naturally aspirated (NA) or turbocharged-aftercooled (TA), depending on rating chosen |
| Compression ratio | 9.7:1 |
| Emissions | Rich-burn combustion. NSPS site-compliant capable with factory-supplied air/fuel ratio control and customer-supplied aftertreatment (three-way catalyst). Distinct from the separate lean-burn G3408C variant - not the same emissions package. |
| Ignition system | Altronic III electronic ignition |
| Rotation / flywheel | Counterclockwise from the flywheel end; SAE No. 0 flywheel housing |
Weights
| Dry weight (bare engine) | 2041-2245 kg (4500-4950 lb). Varies by configuration/package - gas-compression-duty build vs industrial-duty build carry slightly different accessory loadouts. |
| Ground pressure | Not applicable - stationary industrial engine, not tracked or wheeled equipment. |
Dimensions
| Length | 1738-1756 mm (68.0-69.1 in), varies by configuration |
| Width | 1312-1563 mm (51.7-61.5 in), varies by configuration |
| Height | 1542-1758 mm (60.7-69.2 in), varies by configuration |
| Envelope note | Bare-engine footprint only; excludes radiator, skid base, or aftertreatment package where fitted. No wheelbase, track gauge, or ground clearance figures apply - not a mobile chassis. |
Performance
| Rated speed range | 1500-1800 rpm, continuous duty |
| Fuel consumption | About 10.62 MJ/bkW-hr (7507 Btu/bhp-hr), LHV basis, at 100% load on the 1500 rpm rating |
| Duty class / application | Continuous-duty gas compression and industrial power: gas lift, gas gathering, wellhead gas compression, and general industrial mechanical drive |
| Mobility performance | Not applicable - stationary industrial engine. No travel speed, digging, lifting, or drawbar performance figures are published for the bare engine. |
Service capacities (summary)
| Fuel supply | Not applicable - runs on supplied field or pipeline gas; no onboard fuel tank |
| Hydraulic system | Not applicable - no onboard hydraulic system on the bare engine |
| Engine oil (lube system refill) | 46.2 L (12.2 US gal) |
| Cooling system | 54.9 L (14.5 US gal) |
| Oil change interval | About 750 hours under normal service - verify against the current Cat maintenance schedule for your rating and fuel |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
G3408 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (oil, with filter) | 46.2 L (12.2 US gal) refill capacity, engine only | Cat NGEO (Natural Gas Engine Oil) family - Ultra 40, Advanced 40, or standard NGEO - SAE 40, a low-ash oil formulated for spark-ignited gas engines. Do not use diesel or gasoline engine oil, and do not use a multigrade oil. Ambient temperature range for SAE 40 is 5 to 50 deg C (41 to 122 deg F); ask your dealer about a synthetic option outside that range. Standard oil-change interval is 750 hours; adjust with S-O-S oil analysis, especially on sour or bio-gas fuel. |
| Cooling system (jacket water) | 54.9 L (14.5 US gal), engine only. A radiator, aftercooler circuit, or expansion tank adds to this figure and is matched to the specific installation, so total system volume varies by site package. | Cat NGEC (Natural Gas Engine Coolant) is preferred, used as a 50/50 glycol-water premix. Cat DEAC is an acceptable alternate. Extended Life Coolant (ELC) is not approved for Cat gas engines. A 50 percent glycol/water mix protects to about -37 deg C (-34 deg F); do not exceed 60 percent glycol. Maintain supplemental coolant additive at the scheduled interval. |
| Fuel system | No onboard fuel tank - not applicable. The engine runs on gaseous fuel fed from an external supply (pipeline natural gas, wellhead or field gas, digester or landfill bio-gas, or an approved propane arrangement) through a gas pressure regulator and carburetor, not from a machine-carried tank. | Factory-adjusted for pipeline-quality dry natural gas with a low heat value near 33.5 to 34.6 kJ/L (900 to 930 Btu/cu ft). Sour, bio-, or landfill gas needs added fuel treatment and finer filtration; have the fuel analyzed and consult your dealer before use. |
| Grease (external lubrication points) | Not published for this engine - any grease points are hand-serviced with no listed fill quantity. | General-purpose Cat grease, NLGI 2 (for example lithium-complex Cat Utility Grease), for moderate-duty external points such as accessory drives or couplings if fitted. No model-specific grease chart is published for this bare industrial engine; confirm any grease points with your dealer. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar G3408 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 750 h |
|
| Every 1,500 h |
|
| Every 3,000 h |
|
| Every 4,000 h |
|
| Every 10,000 h |
|
| Every 20,000 h |
|
| Every 24,000 h |
|
Servicing the G3408 beyond the schedule
Predictive Maintenance & Fluid Analysis
Pull an engine oil sample every 250 hours and track TBN against the sulfur content of the field gas being burned - rich-burn G3408s see fuel quality swing more than diesel units nearby. Take a Level 1 coolant sample at every 750-hour service and a full Level 2 panel at 3,000 hours to catch liner cavitation and SCA depletion early. Log crankcase blowby and cylinder pressure at the 1,500-hour check; a rising blowby trend usually shows up in spark plug condition before it shows up in an oil report.
Corrective & Common Repairs
Most field calls on a G3408 trace to fuel and ignition, not the block. Spark plug fouling and ignition-timing drift are the top nuisance failures on a rich-burn engine - re-gap or replace plugs and recheck timing at every 750-hour service. Watch the carburetor air-fuel ratio and gas regulator for drift showing up as detonation or power loss. On mechanical-governor units, worn actuator linkage causes hunting; lubricate and inspect it at 1,500 hours. Clean the aftercooler core on turbocharged units when inlet air temperature climbs.
Overhaul & Rebuild Points
Plan a top end overhaul between 9,000 and 14,000 hours depending on aspiration, covering heads, valves, pistons, rings, and liners. Major overhaul follows around 18,000 to 28,000 hours and reaches the crankshaft, main and rod bearings, camshaft, and wet-liner seals. The G3408's diesel-strength block and wet-liner design, shared heritage with Cat's mobile 3408 V-8, make in-frame rebuilds economical against a full engine swap. After either overhaul, recalibrate the governor and ignition timing and re-baseline oil and coolant sampling before returning the unit to continuous duty.
Seasonal & Environment Servicing
Field-sited G3408s run outdoors year-round, so seasonal prep matters more than on a shop engine. Before cold weather, confirm jacket-water heater operation, check coolant freeze protection, and verify starting aids and battery condition - a mechanical governor and digital ignition don't tolerate a slow crank well. Watch fuel gas moisture in winter; condensation can ice the gas pressure regulator. In dusty or sandy wellsite locations, service the air cleaner element and precleaner more often than the standard interval, and remember naturally aspirated ratings derate with altitude and ambient temperature.
G3408 common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 1D-4540 | Bolt,Machine Fuel Filter Mounting | Fuel system service | Check fitment → |
| 6N-6444 | Filter Element As-Air | Air intake service | Check fitment → |
| 6I-2507 | Filter Element As-Air | Air intake service | Check fitment → |
| 6I-2508 | Filter Element As-Air | Air intake service | Check fitment → |
| 1H-5514 | Bolt,Machine Engine Oil Filter Assembly | Lubrication service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
G3408 fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| AL1 | High engine coolant temperature alarm/shutdown | Low coolant level, restricted radiator or heat exchanger, weak water pump, stuck thermostat, or a drifted coolant temperature sensor | Verify actual coolant temperature with a shop gauge, check coolant level and flow, inspect the cooling circuit for restriction, then confirm the sensor reading against the panel setpoint before reset |
| AL2 | Low engine coolant temperature alarm | Engine run below normal operating temperature, a stuck-open thermostat, or a failed jacket-water heater on a standby unit | Let the engine reach normal operating temperature under load, check thermostat operation, and verify the jacket-water heater circuit if the unit sits in standby service |
| AL3 | Low engine oil pressure alarm/shutdown | Low oil level, worn oil pump or bearings, a plugged filter, or a faulty oil pressure sensor/wiring | Check oil level and condition first, confirm actual pressure with a mechanical gauge at the block, then inspect the filter and sensor wiring before returning the unit to service |
| AL5 | Low engine coolant level alarm/shutdown | External coolant leak, trapped air at the coolant-loss probe, or a failed probe | Inspect hoses, gaskets, and the heat exchanger for leaks, bleed air from the system, and verify probe continuity before clearing the fault |
| AL6 | High engine oil temperature alarm/shutdown | Low oil level, a fouled or restricted oil cooler, sustained high load/ambient operation, or sensor drift | Check the oil cooler for restriction, confirm oil level and grade, and verify the sensor reading before reset |
| SP1 / SP2 / SP3 | Spare input alarm or shutdown fault - function is customer-assigned at commissioning, not fixed by the panel | Commonly wired to low fuel-gas supply pressure, high vibration, or an auxiliary safety switch; can also be a short to battery positive or negative in that circuit | Check the panel's setpoint/wiring record to identify what that spare input monitors on this unit, then troubleshoot that specific field circuit for an out-of-range condition or wiring short |
| Overspeed (dedicated shutdown indicator lamp, no digit code) | Engine speed exceeded the shutdown trip point | Governor malfunction, binding or disconnected governor linkage, or sudden loss of driven load | Do not restart until the governor and linkage are inspected; check the speed-sensing wiring and confirm the governor setpoint before returning the unit to service |
| Emergency Stop (dedicated shutdown indicator lamp, no digit code) | An E-stop circuit was opened | A manual E-stop station was pressed, or there is a break/fault in the E-stop loop wiring | Locate and reset the tripped E-stop station, then inspect the E-stop loop wiring for damage before restart |
| Overcrank / Fail-to-Start (dedicated shutdown indicator lamp, no digit code) | Engine failed to start within the panel's cranking-cycle limit | Fuel gas not reaching the mixer (shutoff valve or low supply pressure), an ignition fault, weak cranking from a low battery or worn starter, or governor fuel limit set too low | Confirm fuel gas delivery and ignition spark are present, check cranking speed and battery condition, then re-attempt the start per the panel's crank-cycle sequence |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
G3408 attachments & work tools
Aspiration / turbocharging configuration
Built as naturally aspirated or turbocharged-aftercooled (TA). Aspiration and rated speed (1500 or 1800 rpm depending on gas-compression vs industrial/generator duty) set the power band for a given unit; check the nameplate before assuming a config.
Governor and speed control
Standard governing is a Woodward PSG mechanical governor. Electric, pneumatic, or electronic speed-control governors are offered as options for tighter speed regulation on compression or generator-set duty.
Flywheel / driven-equipment coupling
Engine uses an SAE No. 0 flywheel and flywheel housing with SAE standard rotation. This is the mounting interface for coupling to a gas-compressor frame or AC generator end, not a quick-attach tool interface. No ground-engaging work tools or buckets apply to this engine.
Cooling system arrangement
Standard cooling is an engine-driven jacket-water radiator with an integral aftercooler core. A heat-exchanger cooling option and a non-sparking blower-fan arrangement are available for enclosed or hazardous-area installs, and a higher-heat-rejection radiator group is offered for hot-climate sites.
Starting, charging and ignition
Digital ignition is standard equipment. Electric or air starting systems and charging-alternator options are selected per packager and site power availability.
Fuel system flexibility
The engine is built to run on a range of gaseous fuels. Fuel-system conversion kits let a packager set it up for natural gas or propane depending on site supply.
Control panel (generator-set packages)
When built into a generator set, panel choice runs from a basic analog gauge panel up to a digital control-and-protection panel, selected by the set packager rather than fixed to the bare engine.
Packaging / enclosure
Common package formats are an open skid base for gas-compression or oilfield sites, or a weatherproof, sound-attenuated enclosure for prime/standby generator-set builds.
All G3408 assemblies by section
Every catalogued assembly group for the Caterpillar G3408. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Air Inlet And Exhaust System
2w-1432 Aftercooler Gp-Treated Water -Sea Air
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 4 |
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 4 |
| 1F***58 | Nut-Full; (1/2-13-Thd)(Air Lines) | 4 |
4p-3445 Air Cleaner Gp
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 4 |
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 4 |
| 1F***58 | Nut-Full; (1/2-13-Thd)(Air Lines) | 4 |
6i-2593 Air Cleaner Gp
| 2S***04 | Rod Assem. (Long) | 2 |
| 6I***93 | Air Cleaner Group | 1 |
| 6N***23 | Cup As-Air Cleaner | 1 |
8n-8934 Air Cleaner Gp
| 03***67 | Connector-Flared -- Adapter To Hose As. | 2 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 1 |
| 0T***02 | Bolt; (3/8-16x0.625-In)(Shield To Head) | 4 |
145-3251 Bypass Gp-Exhaust
| 14***51 | Bypass Group-Exhaust | 1 |
4p-6023 Bypass Gp-Exhaust
| 11***72 | Diaphragm | 1 |
| 12***59 | Base As | 1 |
| 14***49 | Valve | 1 |
4w-5828 Cap As-Air Cleaner
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 4 |
| 12***63 | Wheel-Compressor | 1 |
| 1P***20 | Ring-Seal | 1 |
7w-3291 Cartridge Gp-Turbocharger
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 3 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 4 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 3 |
4p-3449 Lines Gp-Air
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 4 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 3 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 2 |
149-3826 Lines Gp-Air
| 01***50 | Plug To Aftercooler Inlet Elbow | 8 |
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 3 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 6 |
105-4663 Manifold Gp-Exhaust
| 03***37 | Spacer; (10.93x19.05x25.4-mm Thk) | 1 |
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 1 |
| 0L***70 | Bolt (2-1/4") Filler Tube Assembly To Transfer Drive Case | 1 |
4p-3442 Mounting Gp-Air Cleaner
| 16***00 | Locknut; (High Temperature) | 4 |
| 4P***42 | Mounting Group-Air Cleaner | 1 |
| 4W***66 | Turbocharger Group | 1 |
4w-6166 Turbocharger Gp
| 2W***20 | Valve-Control | 1 |
| 32***82 | Knob | 1 |
| 4W***66 | Turbocharger Group | 1 |
2w-1735 Turbocharger Gp
| 1B***74 | Plug,Pipe Base Assembly,Engine Oil Filter Assembly | 7 |
| 2W***35 | Turbocharger Group | 1 |
| 7C***07 | Housing As-Turbine | 1 |
4w-5424 Valve Gp-Air Control
| 4W***24 | Valve Group-Air Control; (Engine Start Control) | 1 |
| 7N***79 | Socket-Governor Solenoid Wire To Housing | 1 |
| 7N***80 | Pin-Connector; (14-Ga To 18-Ga) | 1 |
Basic Engine
4n-1092 Balancer Gp
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 4 |
| 1B***82 | Bolt (1.25 In. Long X .313 In. Dia.) | 1 |
| 1W***49 | Shaft-Balance Weight | 1 |
4p-7333 Camshaft Gp
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 2 |
| 10***74 | Gear-Camshaft Drive; (86-Teeth) | 1 |
| 1B***05 | Key; (Woodruff) | 1 |
154-8723 Clutch & Mounting Gp
| 0V***75 | Screw,Cap,Hexagon H Shaft Mtg,Accessory Drive | 8 |
| 11***93 | Valve-Release | 1 |
| 13***04 | Coupling | 1 |
139-5604 Clutch & Mounting Gp
| 0V***75 | Screw,Cap,Hexagon H Shaft Mtg,Accessory Drive | 8 |
| 11***93 | Valve-Release | 1 |
| 13***04 | Coupling | 1 |
134-3113 Clutch Gp
| 13***13 | Clutch Group | 1 |
150-9165 Clutch Gp
| 15***65 | Clutch Group | 1 |
| 15***52 | Element As-Clutch | 1 |
| 15***55 | Seal; (Oil) | 1 |
154-8062 Clutch Gp
| 15***52 | Element As-Clutch | 2 |
| 15***55 | Seal; (Oil) | 1 |
| 15***56 | Drum | 1 |
134-0668 Control Gp-Clutch
| 00***04 | Reducer | 1 |
| 03***77 | Tee-Pipe | 1 |
| 0S***15 | Bolt 19 mm (.75 In.) Long Return Air Console To Enclosed Rops | 6 |
162-2916 Cover Gp-Cylinder Block
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 2 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 6 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 8 |
4w-6732 Cover Gp-Flywheel Housing
| 0S***89 | Bolt, Hex. Hd., 5/8"-11 N.C. X 1 3/4" | 3 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 5 |
| 0S***19 | Bolt,Machine Gear Retaining Part Of Kit P/N 1w***46 | 1 |
213-0479 Cover Gp-Front Housing
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 6 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 3 |
| 10***98 | Cover As-Ring | 1 |
107-7528 Cover Gp-Front Housing
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 6 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 3 |
| 10***28 | Cover Group-Front Housing; Cover Gp-Front Structure | 1 |
4w-1544 Cover Gp-Oil Pan -Engine
| 06***58 | Seal-O-Ring; (Oil Pan Drain Plug) | 1 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 1 |
| 10***72 | Seal-O-Ring; (40.64-mm Id) | 1 |
124-7655 Cover Gp-Valve Mechanism
| 10***20 | Cover-Valve Mechanism | 1 |
| 12***55 | Cover Group-Valve Mechanism | 1 |
| 7C***14 | Adapter | 2 |
124-7656 Cover Gp-Valve Mechanism
| 12***55 | Cover Group-Valve Mechanism | 2 |
| 12***56 | Cover Group-Valve Mechanism | 1 |
| 12***58 | Base-Cover | 2 |
1w-5009 Crankshaft As
| 1W***09 | Crankshaft As | 1 |
| 4N***84 | Dowel; (.75 Long) | 1 |
| 7N***91 | Gear-Crankshaft; (80-Teeth) | 1 |
251-2302 Crankshaft Gp
| 1W***09 | Crankshaft As | 1 |
| 25***02 | Crankshaft Group | 1 |
| 25***52 | Plate-Thrust; (Crankshaft) | 2 |
1w-5010 Crankshaft Gp
| 1W***09 | Crankshaft As | 1 |
| 1W***10 | Crankshaft Group; Crankshaft Group | 1 |
| 24***18 | Kit-Crankshaft Bearing | 0 |
110-3779 Cylinder Block As
| 11***20 | Seal-O-Ring; (Mid-Liner) | 8 |
| 11***79 | Cylinder Block As | 1 |
| 14***17 | Seal-O-Ring; (140.20mm Id) | 8 |
110-3778 Cylinder Block Gp
| 11***78 | Cylinder Block Group | 1 |
| 11***79 | Cylinder Block As | 1 |
| 15***10 | Tube As-Oil Jet | 8 |
206-7747 Cylinder Head As
| 10***73 | Seal-O-Ring; (43.82mm Id) | 4 |
| 20***47 | Cylinder Head As | 1 |
| 21***36 | Seat-Valve; (Exhaust)(Standard) | 8 |
180-8065 Cylinder Head As
151-5242 Cylinder Head As
| 12***52 | Insert-Valve Seat; (Inlet)(Standard) | 8 |
| 13***45 | Insert-Valve Seat; (Inlet 0.13-mm Os Od) | 0 |
| 13***46 | Insert-Valve Seat; (Inlet 0.25-mm Os Od) | 0 |
151-1334 Cylinder Head As
| 12***52 | Insert-Valve Seat; (Inlet)(Standard) | 8 |
| 13***45 | Insert-Valve Seat; (Inlet 0.13-mm Os Od) | 0 |
| 13***46 | Insert-Valve Seat; (Inlet 0.25-mm Os Od) | 0 |
199-3206 Cylinder Head As
| 12***52 | Insert-Valve Seat; (Inlet)(Standard) | 8 |
| 13***45 | Insert-Valve Seat; (Inlet 0.13-mm Os Od) | 0 |
| 13***46 | Insert-Valve Seat; (Inlet 0.25-mm Os Od) | 0 |
198-6526 Cylinder Head As
| 12***52 | Insert-Valve Seat; (Inlet)(Standard) | 8 |
| 13***45 | Insert-Valve Seat; (Inlet 0.13-mm Os Od) | 0 |
| 13***46 | Insert-Valve Seat; (Inlet 0.25-mm Os Od) | 0 |
123-7336 Cylinder Head As
| 12***52 | Insert-Valve Seat; (Inlet)(Standard) | 8 |
| 12***84 | Guide-Valve; (Exhaust) | 8 |
| 12***85 | Guide-Valve; (Inlet) | 8 |
126-7577 Cylinder Head Gp
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 14 |
| 12***77 | Cylinder Head Group | 1 |
| 15***77 | Cylinder Head Group | 2 |
216-8341 Cylinder Head Gp
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 14 |
| 1A***83 | Bolt (4.75" Long-Location "B") | 2 |
| 21***41 | Cylinder Head Group | 1 |
180-7995 Cylinder Head Gp
| 10***14 | Valve-Exhaust | 8 |
| 12***53 | Valve-Inlet | 8 |
| 18***95 | Cylinder Head Group | 1 |
123-7337 Cylinder Head Gp
| 10***14 | Valve-Exhaust | 8 |
| 12***53 | Valve-Inlet | 8 |
| 12***37 | Cylinder Head Group | 1 |
151-6277 Cylinder Head Gp
| 10***14 | Valve-Exhaust | 8 |
| 12***53 | Valve-Inlet | 8 |
| 15***42 | Cylinder Head As | 1 |
198-6528 Cylinder Head Gp
| 10***14 | Valve-Exhaust | 8 |
| 12***53 | Valve-Inlet | 8 |
| 19***26 | Cylinder Head As | 1 |
161-8994 Cylinder Head Gp
| 15***77 | Cylinder Head Group | 1 |
| 16***94 | Cylinder Head Group | 1 |
| 2N***74 | Gasket-Adapter | 4 |
200-0609 Cylinder Head Gp
| 19***28 | Cylinder Head Group | 1 |
| 20***09 | Cylinder Head Group | 1 |
| 21***18 | Adapter | 4 |
200-0614 Cylinder Head Gp
| 10***14 | Valve-Exhaust | 8 |
| 12***53 | Valve-Inlet | 8 |
| 19***06 | Cylinder Head As | 1 |
300-5525 Cylinder Head Gp
| 20***47 | Cylinder Head As | 1 |
| 21***32 | Valve-Inlet | 8 |
| 21***33 | Valve-Exhaust | 8 |
1n-3473 Flywheel Gp
| 0S***02 | Bolt; (5/8-18x3.5-In) | 12 |
| 1N***72 | Cylinder Block Group | 1 |
| 1N***73 | Flywheel Group | 1 |
7n-2840 Gear Gp-Front -Timing
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 1 |
| 11***17 | Plate-Thrust | 1 |
| 11***12 | Shaft-Drive Idler | 1 |
4n-3825 Gear Gp-Rear
| 1B***75 | Bolt (" " " ); Bolt ( " " " ) | 4 |
| 4N***25 | Gear Group-Rear; Rear Timing Gear Group | 1 |
| 4W***85 | Gear-Camshaft; (86-Teeth) | 1 |
136-0453 Guard Gp-Coupling
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 8 |
| 0S***21 | Bolt --Brace To Starting Engine Mounting Pad; Bolt-- Brace To Starting Engine Mounting Pad | 16 |
| 13***53 | Guard Group-Coupling | 1 |
136-3486 Guard Gp-Damper
| 13***67 | Guard As-Damper | 1 |
| 13***69 | Cover As-Damper | 1 |
| 13***86 | Guard Group-Damper | 1 |
4w-6115 Housing Gp-Flywheel
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 4 |
| 0T***73 | Bolt (3/8) (63.5mm Long) (On Cab Of Cover Assem.) | 4 |
| 16***93 | Gasket-Cylinder | 1 |
184-1667 Housing Gp-Front
| 18***65 | Housing-Drive | 1 |
| 18***67 | Housing Group-Front | 1 |
| 1W***29 | Shaft-Drive; (Idler & Governor) | 2 |
4n-5226 Housing Gp-Front
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 3 |
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 2 |
| 16***45 | Gasket-Cylinder Block | 1 |
184-1666 Housing Gp-Rear
| 18***66 | Housing Group-Rear | 1 |
| 3S***13 | Plug,Machine Thread Cylinder Block | 1 |
| 6F***97 | Bearing-Sleeve | 1 |
134-3178 Isolator-Mounting
| 13***78 | Isolator-Mounting | 1 |
110-6230 Lifting Gp-Engine
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 4 |
| 10***57 | Bracket-Lifting; (Front, Rh) | 1 |
| 10***58 | Bracket-Lifting; (Rear, Lh) | 1 |
130-1665 Mounting Gp-Coupling
| 0S***21 | Bolt --Brace To Starting Engine Mounting Pad; Bolt-- Brace To Starting Engine Mounting Pad | 1 |
| 11***48 | Washer; (13.5x86x9.5mm Thk) | 1 |
| 13***64 | Coupling | 1 |
148-9800 Mounting Gp-Engine
| 0S***89 | Bolt, Hex. Hd., 5/8"-11 N.C. X 1 3/4" | 7 |
| 12***24 | Support As | 1 |
| 14***44 | Dowel | 2 |
130-2468 Mounting Gp-Engine
| 12***45 | Plate-Spacer | 2 |
| 12***67 | Block-Weld | 2 |
| 13***68 | Mounting Group-Engine | 1 |
130-1539 Mounting Gp-Refrigerant Compr
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 2 |
| 12***83 | Flange | 1 |
| 12***52 | Block | 2 |
132-9484 Mounting Gp-Transmission
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 4 |
| 12***47 | Block | 4 |
| 12***72 | Plate | 4 |
4w-1540 Pan Gp-Oil -Engine
| 1W***93 | Pan-Oil; (Oil) | 1 |
| 2P***03 | Bolt-Washer Head; (3/8-16x1.25-In) | 32 |
| 3B***51 | Plug (Use Without Low Temperature Sensor) | 3 |
133-3837 Piston & Rod Gp
| 10***79 | Ring-Piston; (Oil Regulator) | 1 |
| 10***47 | Ring-Piston; (Top) | 1 |
| 13***36 | Ring-Piston; (Intermediate) | 1 |
123-8974 Rocker Arm Gp
| 00***03 | Ring-Retaining | 2 |
| 0L***22 | Plug (.656" Dia.) | 2 |
| 10***12 | Rocker Arm As | 4 |
319-7401 Seal Gp-Crankshaft -Front
| 14***67 | Seal Group-Crankshaft; (Front) | 1 |
| 31***01 | Seal Group-Crankshaft; -Front | 1 |
319-0785 Seal Gp-Crankshaft -Rear
| 14***68 | Seal-Crankshaft; (Rear)(Flywheel Housing) | 1 |
| 31***85 | Seal Group-Crankshaft; -Rear | 1 |
2w-9183 Support Gp-Engine -Front
| 0S***73 | Bolt (102mm Long); (1/2-13x4-In) | 8 |
| 2M***49 | Washer-Retainer To Fan Bracket Assembly | 12 |
| 2W***83 | Support Group-Engine; -Front | 1 |
132-9580 Transmission Gp-Ind
| 12***97 | Pallet-Oil | 1 |
| 13***83 | Gearbox | 1 |
| 13***80 | Transmission Group-Ind | 1 |
6i-0244 Valve Mechanism Gp
| 10***16 | Bridge As-Valve; (Inlet) | 8 |
| 10***17 | Bridge As-Valve; (Exhaust)(Each Includes) | 8 |
| 10***39 | Lifter As-Valve | 16 |
Cooling System
7w-2206 Cooler Gp-Engine Oil
| 10***77 | Seal-O-Ring; (100.97mm Id) | 2 |
| 7C***39 | Core As; (Engine Oil Cooler) | 1 |
| 7W***06 | Cooler Group-Engine Oil | 1 |
6n-0671 Filler & Cap Gp -Radiator
| 0S***15 | Bolt 19 mm (.75 In.) Long Return Air Console To Enclosed Rops | 6 |
| 3L***93 | Tube-Overflow | 1 |
| 4L***36 | Gasket | 1 |
130-1537 Heat Exchanger
| 12***95 | Seal-Plate | 2 |
| 13***37 | Heat Exchanger | 1 |
| 14***06 | Plate-Channel | 44 |
130-1561 Heat Exchanger
| 13***61 | Heat Exchanger | 1 |
4n-7414 Lines Gp-Water -Bypass
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 1 |
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 2 |
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 1 |
135-6298 Lines Gp-Water -Aftercooler
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 4 |
| 13***17 | Elbow | 2 |
| 13***98 | Lines Group-Water; -Aftercooler | 1 |
168-2345 Lines Gp-Water
| 03***64 | Nipple | 1 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 4 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 8 |
111-6835 Lines Gp-Water -Turbocharger Cooling
| 00***04 | Elbow | 1 |
| 00***25 | Elbow-Flared | 1 |
| 03***44 | Elbow; (Swivel - 37 Degree Flared) | 1 |
7w-1619 Lines Gp-Water
| 00***04 | Elbow | 1 |
| 00***25 | Elbow-Flared | 1 |
| 03***44 | Elbow; (Swivel - 37 Degree Flared) | 1 |
124-8547 Lines Gp-Water
| 03***64 | Nipple | 1 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 4 |
| 12***80 | Elbow-Flared | 1 |
178-3233 Lines Gp-Water
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 2 |
| 10***73 | Washer; (13.5x40x5-mm Thk) | 2 |
| 12***57 | Plate | 2 |
130-6319 Lines Gp-Water
| 01***50 | Plug To Aftercooler Inlet Elbow | 1 |
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 4 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 1 |
139-5640 Mounting Gp-Heat Exchanger
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 4 |
| 13***40 | Mounting Group-Heat Exchanger | 1 |
| 7W***48 | Gasket-Accessory Drive | 1 |
9y-1268 Pump Gp-Auxiliary Water -Fresh Water
| 1B***02 | Key-- Adapter To Compression Release Shaft | 1 |
| 1N***20 | Ball Bearing | 1 |
| 1N***26 | Shim; (0.005-In Thk) | 1 |
9y-7472 Pump Gp-Auxiliary Water
| 1B***02 | Key-- Adapter To Compression Release Shaft | 1 |
| 1N***20 | Ball Bearing | 1 |
| 1W***48 | Gear-Drive; (21-Teeth)(21 Teeth) | 1 |
227-9843 Pump Gp-Auxiliary Water
| 10***49 | Adapter-Inlet | 1 |
| 11***79 | Seal-O-Ring | 1 |
| 11***80 | Seal-O-Ring | 1 |
137-1338 Pump Gp-Water
| 13***38 | Pump Group-Water | 1 |
102-0457 Pump Gp-Water
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 1 |
| 10***57 | Pump Group-Water | 1 |
| 10***30 | Bearing As-Roller | 1 |
189-0855 Strainer As
| 00***40 | Connector; (Flared) | 1 |
| 10***64 | Mount-Sandwich | 2 |
| 18***55 | Strainer As | 1 |
105-8042 Switch Gp-Coolant Level
| 0S***15 | Bolt 19 mm (.75 In.) Long Return Air Console To Enclosed Rops | 6 |
| 10***42 | Switch Group-Coolant Level | 1 |
| 13***65 | Tank As | 1 |
131-2426 Tank Gp-Coolant
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 18 |
| 0S***19 | Bolt,Machine Gear Retaining Part Of Kit P/N 1w***46 | 2 |
| 0T***73 | Bolt (3/8) (63.5mm Long) (On Cab Of Cover Assem.) | 6 |
Electrical And Starting System
7w-0408 Battery Charger
| 13***72 | Fuse; (12-Ampere) | 1 |
| 13***74 | Fuse; (15-Ampere) | 1 |
| 13***75 | Fuse; (35-Ampere) | 1 |
131-0832 Battery Charger Gp
| 13***32 | Battery Charger Group | 1 |
| 1M***19 | Bolt; (5/16-18x1.375-In)(5/16-18x1.375 In) | 2 |
| 1M***20 | Nut-Battery Terminal (5/16-18 Thd); (5/16-18-Thd)(5/16-18x1.375 In) | 2 |
9x-9730 Battery Gp -Dry
| 9X***30 | Battery Group; (12 Volt)(Dry)(Each Includes) | 1 |
7l-7872 Battery Gp
| 1M***19 | Bolt; (5/16-18x1.375-In)(5/16-18x1.375 In) | 2 |
| 1M***20 | Nut-Battery Terminal (5/16-18 Thd); (5/16-18-Thd)(5/16-18x1.375 In) | 1 |
| 1S***51 | Terminal-Cable; (00-Ga, 1/2-In Screw) | 2 |
7w-0825 Cable Gp-Battery
| 00***28 | Nipple; (Close)(1/4-18 Npt) | 1 |
| 14***23 | Valve Group-Solenoid | 1 |
| 3B***24 | Bushing To Manifold | 1 |
4w-2642 Contactor-Pressure
| 20***27 | Control Group-Engine Electronic | 1 |
| 4W***42 | Contactor-Pressure; (Engine) | 1 |
7e-5717 Control Gp-Air Starting
| 10***87 | Bolt; (M5x0.8x12-mm) | 2 |
| 2H***15 | Washer; (0.219x0.41x0.031-In Thk) | 4 |
| 6V***79 | Seal-O-Ring; (72.62-mm Id) | 1 |
205-0627 Control Gp-Engine Electronic
| 11***43 | Seal-O-Ring | 1 |
| 13***51 | Seal; (Pressure Relief) | 1 |
| 20***27 | Control Group-Engine Electronic | 1 |
128-2500 Control Gp-Engine Electronic
| 11***43 | Seal-O-Ring | 1 |
| 12***00 | Control Group-Engine Electronic | 1 |
| 13***51 | Seal; (Pressure Relief) | 1 |
214-6130 Conversion Gp-Ignition
| 11***43 | Seal-O-Ring | 1 |
| 13***51 | Seal; (Pressure Relief) | 1 |
| 21***45 | Extension-Plug | 1 |
214-6131 Conversion Gp-Ignition
| 11***43 | Seal-O-Ring | 1 |
| 13***51 | Seal; (Pressure Relief) | 1 |
| 21***46 | Insulator | 1 |
226-1801 Conversion Gp-Ignition
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 1 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 1 |
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 3 |
226-1802 Conversion Gp-Ignition
| 1S***93 | Strap; (Cable) (0.62in Dia) | 6 |
| 22***02 | Conversion Group-Ignition | 1 |
| 4P***81 | Clip (For Use With 7.9mm Wide Tie Wrap) | 6 |
132-0140 Fastener Gp-Wiring Harness
| 13***40 | Fastener Group-Wiring Harness | 1 |
113-8966 Fastener Gp-Wiring Harness
| 11***66 | Fastener Group-Wiring Harness | 1 |
| 1A***79 | Capscrew (5/16 - 18 Nc X 1 1/2 Gd5, Hex) | 3 |
| 3E***52 | Washer-Hard; (8.8x20.5x2.5-mm Thk) | 3 |
195-8033 Fastener Gp-Wiring Harness
| 19***33 | Fastener Group-Wiring Harness | 1 |
130-3592 Harness As-Power -Digital Voltage Regulator
| 13***92 | Harness As-Power; -Digital Voltage Regulator | 1 |
139-9150 Harness As-Wiring
| 13***50 | Harness As-Wiring | 1 |
147-7852 Harness As-Wiring
| 10***07 | Kit-Connecting Plug; (2-Pin)(Electronic Control) | 0 |
| 14***52 | Harness As-Wiring | 1 |
195-8025 Harness As-Wiring -Governor
| 19***25 | Harness As-Wiring; -Governor | 1 |
195-8022 Harness As-Wiring -Engine Shutoff
| 19***22 | Harness As-Wiring; -Engine Shutoff | 1 |
147-7855 Harness As-Wiring
| 14***55 | Harness As-Wiring | 1 |
143-6022 Harness As-Wiring
| 14***22 | Harness As-Wiring | 1 |
147-7854 Harness As-Wiring
| 14***54 | Harness As-Wiring | 1 |
| 15***60 | Kit-Connecting Plug; (3-Pin)(Engine Sensor Wiring Harness) | 1 |
| 15***70 | Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
195-8026 Harness As-Wiring -Governor Actuator
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
130-1595 Heater Gp-Jacket Water
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
223-2159 Ignition Gp-Gas Engine
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
124-8611 Ignition Gp-Gas Engine
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
214-2431 Ignition Gp-Gas Engine
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
234-9637 Ignition Gp-Gas Engine
| 00***62 | Elbow-External Pipe Thread | 1 |
| 0S***66 | Bolt-Pulley To Crankshaft Adapter | 4 |
| 1L***87 | Adapter Fitting To Elbow | 1 |
234-9636 Ignition Gp-Gas Engine
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 1 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 10***25 | Clip | 4 |
4p-7352 Mounting Gp-Jacket Wtr Heater
| 10***72 | Seal; (Conduit Hole) | 1 |
| 4P***52 | Mounting Group-Jacket Wtr Heater | 1 |
234-6044 Plug Gp-Box
| 03***46 | Elbow, 90 Deg Adj., 1/4in. J.I.C. X 7/16in.-14 Str. Thd. | 1 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 2 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 6 |
150-6635 Seal Gp-Connector
| 03***46 | Elbow, 90 Deg Adj., 1/4in. J.I.C. X 7/16in.-14 Str. Thd. | 1 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 2 |
| 10***29 | Sensor Group-Speed; -Timing-Engine Speed | 1 |
108-1655 Sensor & Mounting Gp
| 00***40 | Connector; (Flared) | 1 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 2 |
| 10***55 | Sensor & Mounting Group | 1 |
149-3989 Sensor Gp-Engine
| 14***89 | Sensor Group-Engine | 1 |
| 8T***30 | Socket-Connector; (16-Ga To 18-Ga)(Throttle Position Sensor) | 3 |
| 8T***31 | Plug-Connector; (3-Pin) | 1 |
163-8516 Sensor Gp-Pressure
| 16***16 | Sensor Group-Pressure; -Boost And Engine Oil | 1 |
| 4B***81 | Washer--Use With Customer'S Ground Bolt | 1 |
| 8T***29 | Pin-Connector; (16-Ga To 18-Ga)(Throttle Position Sensor) | 2 |
3e-1854 Sensor Gp-Pressure
| 19***26 | Harness As-Sensor; (16-18 Ga Wire)(Engine Oil Temperature) | 1 |
| 19***27 | Harness As-Sensor; (14-Ga Wire)(Engine Oil Temperature) | 1 |
| 3E***54 | Sensor Group-Pressure | 1 |
107-7142 Sensor Gp-Pressure
| 10***42 | Sensor Group-Pressure; Sensor As-Presssure | 1 |
| 18***36 | Socket-Connector; (16-Ga To 18-Ga) | 3 |
| 8L***86 | Seal-O-Ring (Id=16.36mm); (16.36-mm Id) | 1 |
150-5136 Sensor Gp-Speed
| 15***36 | Sensor Group-Speed | 1 |
| 8T***29 | Pin-Connector; (16-Ga To 18-Ga)(Throttle Position Sensor) | 2 |
| 8T***32 | Receptacle-Connector; (3-Pin)(Throttle Position Sensor) | 1 |
102-9029 Sensor Gp-Speed
| 10***29 | Sensor Group-Speed; -Timing-Engine Speed | 1 |
| 11***66 | Seal-O-Ring | 1 |
| 13***07 | Washer; (21.1x28.1x0.9-mm Thk) | 1 |
302-6257 Sensor Gp-Speed
| 10***05 | Cap-Receptacle | 1 |
| 10***42 | Sensor Group-Pressure; Sensor As-Presssure | 1 |
| 11***26 | Sensor Group-Temperature | 1 |
113-9126 Sensor Gp-Temperature
| 10***05 | Cap-Receptacle | 1 |
| 11***26 | Sensor Group-Temperature | 2 |
| 16***16 | Sensor Group-Pressure; -Boost And Engine Oil | 1 |
113-8965 Shutoff Gp-Electrical
| 10***05 | Cap-Receptacle | 1 |
| 10***42 | Sensor Group-Pressure; Sensor As-Presssure | 1 |
| 11***65 | Shutoff Group-Electrical | 1 |
146-8975 Shutoff Gp-Electrical
| 14***75 | Shutoff Group-Electrical | 1 |
| 2N***87 | Elbow-Flared Needed For Customer; (Used Without Brakesaver) | 1 |
| 2S***58 | Washer-Hard; (17x29x3-mm Thk)(Engine Brake) | 3 |
2w-3560 Silencer Gp-Air Starting
| 06***19 | Ball Bearing | 1 |
| 12***34 | Pinion-Drive; (12-Teeth) | 1 |
| 1S***56 | Bearing-Ball | 1 |
2s-7227 Starting Motor Gp-Electric
| 03***21 | Shim Lever Housing | 1 |
| 03***23 | Bolt; (1/4-28x1-In) | 13 |
| 04***65 | Screw 19.05 mm(.750 In.) Long | 4 |
7w-0301 Starting Motor Gp-Air
| 03***21 | Shim Lever Housing | 1 |
| 03***23 | Bolt; (1/4-28x1-In) | 13 |
| 04***65 | Screw 19.05 mm(.750 In.) Long | 4 |
7w-0299 Starting Motor Gp-Air
| 4N***59 | Gasket; (Starting Motor) | 1 |
| 6V***27 | Starting Motor Group-Electric | 1 |
| 7W***99 | Starting Motor Group-Air | 1 |
6v-0927 Starting Motor Gp-Electric
| 3N***54 | Support As-Battery | 1 |
| 3N***55 | Board | 1 |
| 6V***27 | Starting Motor Group-Electric | 1 |
237-1962 Starting Motor Gp-Electric
| 17***08 | Switch Group-Magnetic; -24-Volt-Start Relay-Main Relay | 1 |
| 17***09 | Switch Group-Magnetic; -24-Volt-Start Relay | 1 |
| 23***62 | Starting Motor Group-Electric | 1 |
6v-0890 Starting Motor Gp-Electric
| 03***21 | Shim Lever Housing | 1 |
| 03***23 | Bolt; (1/4-28x1-In) | 13 |
| 04***65 | Screw 19.05 mm(.750 In.) Long | 4 |
3n-7056 Support Gp-Battery
| 01***80 | Lockwasher | 2 |
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 18***35 | Pin-Connector; (16-Ga To 18-Ga) | 2 |
175-2308 Switch Gp-Magnetic
| 11***43 | Seal-O-Ring | 1 |
| 12***38 | Spring-Transformer | 1 |
| 12***14 | Spacer; (23.8x46.02x3.4-mm Thk) | 1 |
175-2309 Switch Gp-Magnetic
| 11***43 | Seal-O-Ring | 1 |
| 12***38 | Spring-Transformer | 1 |
| 12***14 | Spacer; (23.8x46.02x3.4-mm Thk) | 1 |
118-3534 Switch Gp-Magnetic
| 01***80 | Lockwasher | 2 |
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 11***81 | Switch As-Magnetic; (Start Relay) | 1 |
327-9366 Transformer Gp
| 11***43 | Seal-O-Ring | 1 |
| 12***58 | Insulator | 1 |
| 12***71 | Terminal As | 1 |
327-9369 Transformer Gp-Ignition
| 32***69 | Transformer Group-Ignition | 1 |
| 3B***96 | Fitting; (Nipple) | 1 |
| 9X***38 | Plug-Pipe; (Engine Oil Drain) | 1 |
232-6349 Transformer Gp-Ignition
| 23***49 | Transformer Group-Ignition | 1 |
131-3277 Transformer Gp-Ignition
| 11***43 | Seal-O-Ring | 1 |
| 12***38 | Spring-Transformer | 1 |
| 12***14 | Spacer; (23.8x46.02x3.4-mm Thk) | 1 |
327-9367 Transformer Gp-Ignition
| 32***67 | Transformer Group-Ignition | 1 |
| 7X***78 | Coil As | 1 |
232-6353 Transformer Gp-Ignition
| 10***92 | Valve Group-Solenoid; -Gas Shutoff | 1 |
| 23***53 | Transformer Group-Ignition | 1 |
| 4P***77 | Gasket | 1 |
232-6348 Transformer Gp-Ignition
| 11***43 | Seal-O-Ring | 1 |
| 12***38 | Spring-Transformer | 1 |
| 13***51 | Seal; (Pressure Relief) | 1 |
232-6352 Transformer Gp-Ignition
| 0T***20 | Bolt (1.25 In. Long X .438 In. Dia.) | 1 |
| 1H***69 | Button-Spring | 1 |
| 1H***72 | Plate-Pressure | 1 |
123-8273 Transmitter-Pressure
| 10***31 | Valve Group-Solenoid; (Air Start) | 1 |
| 12***73 | Transmitter-Pressure | 1 |
| 5D***69 | Connector--Sealing Grip; Connnector-Sealing Grip | 1 |
9y-6992 Valve Gp-Solenoid
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 0S***18 | Bolt; (5/16-18x1-In)(Hydraulic Pump) | 2 |
| 12***83 | Plug As-Connector; (1-Pin) | 2 |
142-3023 Valve Gp-Solenoid
| 14***23 | Valve Group-Solenoid | 1 |
| 3B***91 | Coupling-Pipe | 1 |
121-4395 Valve Gp-Solenoid
| 12***95 | Valve Group-Solenoid | 1 |
| 14***52 | Harness As-Wiring | 1 |
| 14***54 | Harness As-Wiring | 1 |
103-0692 Valve Gp-Solenoid
| 0S***14 | Bolt (.25" Diameter-.50" Long) | 2 |
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 0S***18 | Bolt; (5/16-18x1-In)(Hydraulic Pump) | 2 |
1l-5011 Valve Gp-Air Starting
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 4 |
| 0S***19 | Bolt,Machine Gear Retaining Part Of Kit P/N 1w***46 | 1 |
| 0T***02 | Bolt; (3/8-16x0.625-In)(Shield To Head) | 4 |
195-8029 Wiring Gp-Engine
| 19***29 | Wiring Group-Engine | 1 |
194-0905 Wiring Gp-Engine
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 4 |
| 19***05 | Wiring Group-Engine | 1 |
| 4D***76 | Boss (2 In Each 6d***81 Assem.) | 2 |
195-8030 Wiring Gp-Engine
| 10***06 | Receptacle Kit; (Includes Wedge And Receptacle Assem.) | 1 |
| 10***13 | Receptacle As-Connector; (70-Pin) | 1 |
| 10***07 | Switch-Operator; (Secondary Stop Push Button) | 1 |
169-5412 Wiring Gp-Shutoff
| 10***13 | Receptacle As-Connector; (70-Pin) | 1 |
| 10***07 | Switch-Operator; (Secondary Stop Push Button) | 1 |
| 11***23 | Block-Contact; (1-Pole)(Normally Open) | 1 |
Enclosures, Guards And Bases
116-2560 Base As
| 11***60 | Base As | 1 |
| 3J***54 | Packing,Preformed Part Of Kit P/N 5r***27 | 1 |
| 9S***02 | Plug-O-Ring; (Straight Thread O-Ring) | 1 |
149-1320 Mounting Gp-Air Pallet
| 14***20 | Mounting Group-Air Pallet | 1 |
| 1S***91 | Screw-Machine; (6-32x.25in) | 16 |
| 2L***77 | Terminal; (14-Ga To 16-Ga, 1/4-In Screw)(14-16 Gage, 6.4mm Screw) | 4 |
160-9800 Pad-Isolator
| 16***00 | Pad-Isolator | 1 |
Engine Arrangement
149-1165 Engine Ar
| 10***57 | Pump Group-Water | 1 |
| 10***28 | Cover Group-Front Housing; Cover Gp-Front Structure | 1 |
| 10***97 | Drive Group-Governor | 1 |
Fuel System
6i-2160 Actuator As-Governor
| 03***13 | Seal-O-Ring | 1 |
| 3F***74 | Nut-Self Locking; (1/4-28 Thd) | 1 |
| 4B***49 | Nut-Valve To Bracket; 3.18mm(.125in)Thk | 1 |
7e-1593 Body As-Carburetor
| 1F***58 | Nut-Full; (1/2-13-Thd)(Air Lines) | 4 |
| 4P***08 | Throttle As | 1 |
| 4P***24 | Washer; (12.7x24x1.49-mm Thk) | 1 |
9y-0830 Carburetor Gp
| 06***40 | Seal-O-Ring (Id=37.69mm) | 1 |
| 09***24 | Screw As; (12-24x0.625-In) | 6 |
| 15***35 | Valve Group-Fuel | 1 |
159-8337 Carburetor Gp
| 0S***16 | Screw,Cap,Hexagon H Receptacle Mtg; Bolt Brackets To Firewall Assembly | 1 |
| 15***37 | Carburetor Group | 1 |
| 1A***85 | Nut,Plain,Hexagon Governor And Decelerator Control | 1 |
4p-3448 Carburetor Gp
| 15***37 | Carburetor Group | 1 |
| 1F***58 | Nut-Full; (1/2-13-Thd)(Air Lines) | 4 |
| 4P***08 | Throttle As | 1 |
2w-1857 Control Gp-Carburetor
| 0L***52 | Capscrew (3/8 - 16 Nc X 3 1/4 Gd8, Hex) | 6 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 3 |
| 10***96 | Ring-Timing | 1 |
107-7897 Drive Gp-Governor
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 2 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 4 |
| 10***43 | Cover-Magneto Drive | 1 |
184-1668 Drive Gp-Governor
| 15***57 | Diaphragm | 1 |
| 15***60 | Plate | 1 |
| 15***61 | Bushing | 1 |
107-8515 Drive Gp-Governor
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 2 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 4 |
| 0S***15 | Bolt 19 mm (.75 In.) Long Return Air Console To Enclosed Rops | 2 |
142-1470 Kit-Carburetor
| 05***41 | Elbow | 1 |
| 06***63 | Connector (No. 8 Hose) | 1 |
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 2 |
4p-3943 Regulator Gp-Gas Pressure
| 13***83 | Spring | 1 |
| 13***84 | Body-Valve; (Gas Pressure Regulator) | 1 |
| 13***86 | Seal-O-Ring | 2 |
104-6775 Regulator Gp-Gas Pressure
| 05***41 | Elbow | 1 |
| 06***63 | Connector (No. 8 Hose) | 1 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 1 |
149-2564 Regulator Gp-Gas Pressure
| 12***09 | Spring | 1 |
| 12***29 | Plate | 1 |
| 12***30 | Piston | 1 |
156-5735 Valve Gp-Fuel
| 15***35 | Valve Group-Fuel | 1 |
Lubrication System
282-1788 Base As-Oil Filter
| 28***88 | Base As-Oil Filter | 1 |
| 2P***04 | Stud-Hollow; (1.5-16x1.339-In) | 2 |
| 3J***54 | Packing,Preformed Part Of Kit P/N 5r***27 | 1 |
2n-8220 Breather Gp -Crankcase
| 2N***09 | Clamp; (V-Band) | 1 |
| 2N***20 | Breather Group; Breather Gp-Crankcase | 1 |
| 4F***90 | Seal (2.10" Inside Diameter) | 1 |
4n-2481 Fastener Gp-Oil Pump Mounting -Engine
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 2 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 1 |
| 4N***81 | Fastener Group-Oil Pump Mounting; Oil Pump Mounting Fastener Group | 1 |
164-5679 Filter Gp-Engine Oil
| 00***12 | Connector-Flared | 2 |
| 06***17 | Elbow-Flared | 1 |
| 0S***84 | Cap Screw (2 1/4" Long) | 12 |
6n-0936 Filter Gp-Engine Oil
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 1 |
| 0L***70 | Bolt (2-1/4") Filler Tube Assembly To Transfer Drive Case | 2 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 9 |
148-6400 Filter Gp-Engine Oil
| 14***99 | Filter Element-Oil | 1 |
| 14***00 | Filter Group-Engine Oil | 1 |
4p-2781 Filter Gp-Engine Oil
| 00***12 | Connector-Flared | 2 |
| 06***17 | Elbow-Flared | 1 |
| 0S***84 | Cap Screw (2 1/4" Long) | 12 |
7c-5154 Fumes Disposal Gp
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 3 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 1 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 2 |
4w-1548 Gauge Gp-Oil Level (Dipstick) -Engine
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 1 |
| 0S***08 | Bolt-Support To Starting Engine Timing Gear Housing | 1 |
| 11***68 | Seal-O-Ring; (15.54mm Id) | 1 |
126-7480 Lines Gp-Engine Oil
| 0L***51 | Bolt Starting Engine Fuel Tank Bracket To Diesel Intake Manifold | 1 |
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 1 |
| 0S***91 | Screw,Cap,Hexagon Bearing Retainer; Part Of Kit P/N 1w***82 | 1 |
149-1188 Lines Gp-Lube Oil
| 00***99 | Connector-Flared | 1 |
| 00***40 | Connector; (37 Degree) | 1 |
| 14***19 | Pipe-Bulk; (288-cm) | 0 |
130-1545 Lines Gp-Lube Oil
| 00***01 | Elbow (To Serial No 1md225) | 1 |
| 00***15 | Tee-Flared | 1 |
| 06***46 | Connector-Flared | 3 |
2w-0587 Lines Gp-Oil Supply
| 03***41 | Elbow; (7/16-20 Str Thd) | 1 |
| 11***27 | Seal-O-Ring; (19.18mm Id) | 1 |
| 2W***68 | Tube As | 1 |
2w-2046 Lines Gp-Turbocharger Oil
| 0L***43 | Bolt 63.5 mm (3/8" X 2 1/2" -Cover Assembly To Fender | 1 |
| 0S***71 | Screw,Cap,Hexagon; Tube Assembly To Turbocharger And Elbow Mounting | 2 |
| 11***87 | Seal-O-Ring (23.16 mm Id) | 1 |
4n-8734 Pump Gp-Engine Oil
| 1M***44 | Bolt; (3/8-16x2-1/4 In) | 2 |
| 1W***38 | Shaft As-Pump Drive; (8-Teeth) | 1 |
| 1W***39 | Shaft As-Idler; (8-Teeth) | 1 |
Operator Station
235-6415 Box Gp-Control Panel
| 23***15 | Box Group-Control Panel | 1 |
| 6V***48 | Control Group-Engine Monitoring | 1 |
| 8C***88 | Seal-Security | 1 |
194-0883 Box Gp-Control Panel
| 19***83 | Box Group-Control Panel | 1 |
| 3E***36 | Film-Identification; (Status) | 1 |
| 3E***48 | Control Group-Engine Monitoring | 1 |
130-3349 Control Gp-Alarm Module
| 03***49 | Nut-Self Lock; (No.10.Unc) | 4 |
| 03***24 | Screw (2 In. Long) | 2 |
| 10***38 | End-Wire; (16-Ga) | 8 |
149-8661 Control Gp-Engine Monitoring
| 12***63 | Circuit Breaker As; (16-Ampere, Single Pole)(16a, 1 Pole) | 1 |
| 12***62 | Circuit Breaker As; (16-Ampere)(16a, 2 Pole) | 1 |
| 12***63 | Circuit Breaker As; (13-Ampere)(13a, 1 Pole) | 1 |
3e-7848 Control Gp-Engine Monitoring
| 3E***48 | Control Group-Engine Monitoring | 1 |
6v-6149 Control Gp-Engine Monitoring -Spark Ignited
| 12***63 | Circuit Breaker As; (16-Ampere, Single Pole)(16a, 1 Pole) | 1 |
| 12***62 | Circuit Breaker As; (16-Ampere)(16a, 2 Pole) | 1 |
| 12***63 | Circuit Breaker As; (13-Ampere)(13a, 1 Pole) | 1 |
3e-8542 Control Gp-Engine Monitoring
| 1P***23 | Kit-Meter Window Service; (Window) | 1 |
| 3E***42 | Control Group-Engine Monitoring | 1 |
| 4M***03 | Packing,Preformed Hourmeter Mtg | 1 |
6v-6148 Control Gp-Engine Monitoring
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 10 |
| 12***03 | Isolator | 3 |
| 12***04 | Isolator | 6 |
4n-2328 Meter Gp-Service
| 10***41 | Spring-Relay | 1 |
| 10***39 | Plate-Separator | 1 |
| 11***43 | Circuit Breaker As; (16-Ampere) | 1 |
131-1717 Mounting Gp-Control
| 13***17 | Mounting Group-Control | 1 |
150-1392 Panel Gp-Control
| 13***34 | Shim; (0.025-mm Thk) | 1 |
| 13***35 | Shim; (0.0508-mm Thk) | 1 |
| 13***36 | Shim; (0.076-mm Thk) | 1 |
147-8599 Panel Gp-Control
| 10***72 | Seal-O-Ring; (40.64-mm Id) | 5 |
| 10***76 | Seal-O-Ring; (50.17mm Id) | 5 |
| 12***52 | Gasket-Exhaust Manifold | 4 |
144-0431 Panel Gp-Control
| 12***63 | Circuit Breaker As; (16-Ampere, Single Pole)(16a, 1 Pole) | 2 |
| 12***22 | Relay-Power | 2 |
| 12***62 | Circuit Breaker As; (16-Ampere)(16a, 2 Pole) | 1 |
147-1964 Panel Gp-Control
| 12***47 | Tag; (Certification) | 1 |
| 13***01 | Film-Control Panel | 1 |
| 13***02 | Film-Identification | 1 |
153-1010 Panel Gp-Control
| 15***10 | Panel Group-Control | 1 |
Service Equipment And Supplies
6l-4502 Chart-Plate & Film
| 6L***02 | Chart-Plate & Film | 1 |
160-4917 Kit-Dowel
| 16***17 | Kit-Dowel | 1 |
231-5226 Kit-Gasket
| 23***26 | Kit-Gasket | 1 |
137-8533 Shim Pack
| 13***33 | Shim Pack; (Includes 13-Shims) | 1 |
G3408 serial number reference
On the G3408 the PIN/serial plate is riveted to the engine block or flywheel housing, usually on the left side near the oil filter base or rear housing - check both spots since mounting varies by package (genset, compressor skid, industrial). Pre-2001 engines show an 8-character serial number; the first 3 letters/digits are the prefix identifying the engine build block, and the following 5 digits are the sequential unit number within that block. Later engines carry a full 17-character PIN where the same 3-character prefix sits at the start of the last 8-character serial segment.
| Prefix | Identifies | Notes |
|---|---|---|
| 6NB | G3408 Gas Engine (naturally aspirated and turbocharged-aftercooled builds both fall under this block) | Used on G3408 gas compression / SITA-package units. Seen on natural-gas generator sets built around 1990. Rated 190-317 bkW (255-425 bhp) at 1800 rpm depending on configuration. |
| 6FW | G3408 Industrial Engine | General industrial/mechanical-drive application of the G3408, a separate nameplate line from the gas-compression package. |
| 8YR | G3408 Industrial/Gas Engine | Classified as both industrial and gas engine across different Caterpillar service listings for this block. |
| N42 | G3408 Engine | Documented in G3408 schematic service literature. Thin record - confirm with dealer before relying on it. |
Frequently asked questions
What engine does the Caterpillar G3408 use?
The G3408 is itself the engine, not a machine powered by a separate one. It is a Caterpillar V-8, four-stroke, rich-burn natural gas engine on the G3400 industrial platform, displacing 18 L (1,099 cu in.) with a 137 mm (5.4 in.) bore and 152 mm (6.0 in.) stroke. It is offered naturally aspirated or turbocharged-aftercooled and rated 190-298 bkW (255-400 bhp) at 1500 or 1800 rpm.
What is the G3408's operating weight?
As a bare industrial engine rather than a mobile machine, the G3408 does not have an operating weight in the excavator or dozer sense. Its net dry engine weight is about 1,678 kg (3,700 lb.) for the base package. Skid-mounted or generator-set packages add weight for the base frame, radiator, and any driven equipment, so installed weight varies by configuration.
What replaced the Caterpillar G3408?
No confirmed direct successor turned up in factory documentation. The G3408 remains part of Caterpillar's current gas-compression engine lineup alongside the higher-output G3408C, which adds electronic ADEM controls and detonation-sensitive ignition timing rather than replacing the G3408 outright. Verify current availability in your region with a Cat dealer.
What G3408 owners discuss
What's the biggest thing to watch for with detonation and spark plug wear on a G3408?
The G3408 runs Cat's Electronic Ignition System with a detonation sensor on each cylinder bank; timing pulls back automatically when detonation is sensed, so a plug that's fouling or wearing fast is often the first sign of marginal fuel quality or a compression-ratio mismatch, showing up before any fault code does. Techs check plug gap growth and firing-end color at every inspection rather than going by a fixed calendar date alone, since fuel gas quality (BTU content, knock resistance) varies well to well and drives plug life more than hours do. If one bank starts pulling timing consistently, have your dealer verify detonation sensor calibration and fuel gas quality before assuming it's just worn plugs.
How does the governor and speed control behave, and what do owners say about tuning it?
Base G3408 packages use a mechanical/pneumatic-type governor with adjustable speed droop, roughly zero to seven percent, and some packages add electric speed-setting through a small actuator motor instead of manual linkage. Operators report the mechanical governor holds steady speed well under compressor load once droop is dialed in, but response feels slower than a full electronic setup, so units seeing frequent load-step changes benefit most from adding electronic speed control. Governor and air-fuel ratio settings interact under rich-burn control, so have your dealer verify droop and speed settings any time the AFR controller is recalibrated.
What's the recurring quirk with jacket water and cooling on this engine?
On turbocharged-aftercooled G3408 packages, the jacket-water circuit also feeds the low-temperature side of the aftercooler loop before running to the radiator or a remote heat exchanger, so a scaled or leaking heat exchanger shows up as rising intake manifold air temperature as much as rising coolant temperature. The classic field symptom mechanics flag is water turning up in an oil sample or on the dipstick, which usually traces to a leaking heat exchanger core or a cracked cylinder head rather than a simple gasket seep. Any coolant-in-oil finding on a gas engine should stop the unit until your dealer verifies the source, since it can mask into detonation on the affected cylinders.
What electrical or sensor problems come up most with the ignition and air-fuel-ratio system?
The ignition module leans on a magnetic speed/timing sensor, a manifold air pressure sensor, and the bank detonation sensors to set spark timing in real time; connector corrosion or a drifting manifold air pressure reading tends to show up as rough idle or intermittent timing pull long before the module logs a hard fault. On rich-burn units running catalyst aftertreatment, the air-fuel-ratio controller's oxygen sensor is a wear item that ages gradually rather than failing outright, and a slowly drifting sensor lets the fuel ratio wander before catalyst efficiency drops enough to trip an emissions alarm. Field practice is to check oxygen sensor response on a set schedule instead of waiting for it to fail outright; have your dealer verify AFR calibration if timing or emissions readings start drifting.
How should oil sampling and change intervals be handled on a gas engine like this versus a diesel?
Gas engine oil ages mainly by additive depletion (total base number) rather than by soot loading, so this engine is normally run on an oil-analysis-driven interval instead of a flat hours number, with samples pulled on a set schedule to track TBN trend alongside wear metals. A rule of thumb techs use is that once TBN drops toward the low single digits it's time to drain regardless of hours, and the ash/TBN oil package needed shifts if the fuel gas carries meaningful sulfur content. Skipping oil analysis on a rich-burn gas engine is a common way owners get surprised by bearing wear that a diesel-style fixed interval would have caught earlier.
Is there a known wear pattern specific to running the 3400 block on natural gas versus diesel duty?
Owners who have run these gas conversions report the 3400 platform holds up well on gas duty, with some reporting engines reaching well into six figures of hours before major bottom-end work, since gas combustion tends to run cleaner on the crank and rings than diesel. The tradeoff mechanics flag is exhaust valve and seat wear: gas-fired operation is harder on valve seating than diesel because the combustion event carries less lubricating film, so valve recession and burnt exhaust valves are the more common top-end wear item over a long service life. Have your dealer verify valve lash and seat condition at major inspection intervals rather than waiting for a compression complaint.
What should someone check before buying a used G3408?
Pull the full service history first: oil analysis trend (TBN, wear metals), any recorded detonation-retard events from the ignition module, and the calibration date on the air-fuel-ratio controller and catalyst if it's a rich-burn package. Physically check spark plug condition and gap across a few cylinders (uneven wear between banks flags a detonation sensor or fuel distribution problem), pull a coolant sample and check for oil contamination, and confirm the heat exchanger or radiator hasn't been repeatedly patched or rodded. Ask for total hours and hours since the last top-end or valve job, since valve and seat condition is the main age-related cost driver on these; have your dealer verify governor and ignition timing settings against current spec before you commit, since a used package's control settings may still reflect a prior application's fuel gas quality and load profile.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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