Caterpillarengine - industrialgas engine
Caterpillar G3408C
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar G3408C is a V-8, 18-liter (1099 in³) natural gas industrial engine built on the G3400 platform. Rated at 317 bkW (425 bhp) at 1800 rpm, it weighs 4500 kg (9921 lb) dry. Production spanned the late 1990s through the 2000s, succeeding the G3408B and preceding the G3408LE. Configurations include EIS (Electronic Ignition System) for gas compression, power generation, and pump drive applications.
The G3408C transitioned from mechanical fuel control to the Cat EIS system, enabling detonation-sensitive timing and diagnostic codes. Its robust diesel-strength design and ability to burn wide-spectrum gaseous fuels made it a staple in gas lift and gathering. In the used market, it remains critical for retrofits and spare parts due to its deep sump capacity and modular block design, which simplify overhauls compared to earlier G3408 variants.
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 G3408C specifications
Engine
| Model | G3408C (Industrial Gas Engine) |
| Configuration | 8-cylinder, 4-stroke, spark-ignited |
| Displacement | 18 L (1099 in³) |
| Bore | 137 mm (5.4 in) |
| Stroke | 152 mm (6.0 in) |
| Gross/Net Power | 190–317 bkW (255–425 bhp) @ 1800 rpm; 249 bkW (332 bhp) @ 1500 rpm |
| Emissions Tier | NSPS site compliant capable (with customer-supplied aftertreatment); standard emission settings available for export only |
Weights
| Dry Weight (Net) | 4500 kg (9922 lb) [per Western States Cat spec sheet]; 4950 lb (2245 kg) [per Cat Industrial spec sheet] |
Dimensions
| Length | 1756 mm (69.1 in) |
| Width | 1563 mm (61.5 in) |
| Height | 1758 mm (69.2 in) |
| Flywheel/Flywheel Housing | SAE No. 0 |
Performance
| Rated Speed | 1500 rpm or 1800 rpm |
| Compression Ratio | 8.5:1 |
| Aspiration | Turbocharged-Aftercooled (TA) or Naturally Aspirated (NA) |
| Rotation from Flywheel End | Counterclockwise |
Service capacities (summary)
| Cooling System | 54.9 L (14.5 gal US) |
| Lube Oil System - Refill | 147.63 L (39 gal US) |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
G3408C fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine Crankcase (with filter) | 147.63 l (39 gal (US)) | Caterpillar Diesel Engine Oil (DEO) or Diesel Exhaust Fluid Oil (TDTO); viscosity varies by ambient temperature per S•O•SSM standards |
| Cooling System | 54.9 l (14.5 gal (US)) | Caterpillar ELC Coolant or Extended Life Coolant (ELC); specific gravity and freeze point vary by climate per factory spec sheet |
| Fuel Tank | Not documented for this exact serial range — verify with your dealer | Not documented for this exact serial range — verify with your dealer |
| Transmission/Powertrain | Not documented for this exact serial range — verify with your dealer | Not documented for this exact serial range — verify with your dealer |
| Final Drives | Not documented for this exact serial range — verify with your dealer | Not documented for this exact serial range — verify with your dealer |
| Hydraulic System and Tank | Not documented for this exact serial range — verify with your dealer | Not documented for this exact serial range — verify with your dealer |
| Axles/Differentials | Not documented for this exact serial range — verify with your dealer | Not documented for this exact serial range — verify with your dealer |
| Grease | Not applicable | Caterpillar Multipurpose Grease (EP2) or equivalent lithium-complex grease; NLGI Grade 2 |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar G3408C maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
Servicing the G3408C beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize S.O.S fluid analysis to monitor lube oil wear metals and coolant glycol content. The G3408C’s deep sump oil pan supports extended intervals only when S.O.S confirms oil integrity. Check coolant pH and SCA concentration every 500 hours to prevent liner pitting. Analyze fuel gas for particulate matter to protect the Fisher pressure regulator. Monitor spark plug maintenance codes via the EIS system to predict misfire trends before they cause cylinder damage.
Corrective & Common Repairs
Address EIS module faults by checking high-voltage wiring harness insulation for heat damage. Replace Fisher gas pressure regulator diaphragms if gas supply pressure fluctuates. Inspect water-cooled exhaust manifolds for carbon buildup at each port. Replace worn crankshaft vibration damper pulleys to prevent harmonic stress. Check cylinder block inspection covers for gasket leaks and ensure side cover bolts are torqued to specification.
Overhaul & Rebuild Points
Rebuild at 20,000 hours or when compression drops below spec. Replace piston rings and cylinder liners during major overhauls. Inspect the crankshaft for journal wear and replace bearings if clearance exceeds limits. Check the flywheel housing for bolt stretch and replace if deformed. Recondition the turbocharger shaft and housing if shaft play exceeds tolerances. Replace all gaskets and seals during block disassembly.
Seasonal & Environment Servicing
In dusty environments, clean air cleaner pre-cleaners daily and replace primary elements at 500 hours. In cold climates, verify expansion tank antifreeze concentration to prevent freezing. Inspect radiator and aftercooler cores for debris buildup to maintain heat rejection. Check battery cables and terminals for corrosion in humid conditions. Verify ignition system grounding in high-vibration applications to prevent EIS signal interference.
G3408C common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 4P-4719 | Filter Element-Fuel | Fuel system service | Check fitment → |
| 8C-8902 | Film | Lubrication service | Check fitment → |
| 9S-8752 | Nut-Full | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
G3408C fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CID 0041 FMI 03 | 8-Volt DC Supply — Voltage Above Normal | Short to power on the 8-volt reference circuit shared by sensors. | Inspect wiring harness for damage; disconnect sensors one by one to isolate the shorted circuit. |
| CID 0041 FMI 04 | 8-Volt DC Supply — Voltage Below Normal | Short to ground on the 8-volt reference circuit. | Disconnect sensors sharing the 8V supply to locate the grounded component. |
| CID 0110 FMI 03 | Engine Coolant Temperature Sensor — Voltage Above Normal | Open circuit or short to supply in the sensor wiring. | Check sensor connector integrity; replace sensor if circuit is confirmed intact. |
| CID 0190 FMI 08 | Engine Speed — Abnormal Frequency | Speed sensor air gap error, sensor failure, or damaged tone ring. | Verify sensor mounting gap; test sensor output and inspect tone ring for damage. |
| CID 0262 FMI 04 | 5-Volt Supply — Voltage Below Normal | Short to ground on the 5-volt reference circuit. | Isolate the fault by disconnecting sensors on the 5V supply circuit sequentially. |
| CID 0268 FMI 02 | Programmed Parameter Fault — Erratic/Incorrect | ECM parameter corruption or loss of calibration data. | Reprogram ECM with latest calibration data via diagnostic tool. |
| CID 03257 FMI 03 | Air Inlet Heater — Voltage Above Normal | Short to power in the air inlet heater relay circuit. | Inspect wiring for chafing or contact with power sources; test heater relay. |
| CID 0164 FMI 03 | Injector Actuation Pressure — Voltage Above Normal | Fault in the actuator pressure sensor or its signal circuit. | Check sensor wiring continuity; replace sensor if wiring is verified good. |
| CID 0248 FMI 09 | CAT Data Link — Abnormal Update Rate | CAN bus wiring damage, poor connection, or termination fault. | Check CAN bus wiring integrity and measure termination resistance at the service port. |
| CID 0091 FMI 05 | Throttle Position Sensor — Current Below Normal | Open circuit in the throttle position sensor wiring. | Inspect harness for breaks; verify sensor connector seating and pin tension. |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
G3408C attachments & work tools
Gas Compression Drives
The G3408C is designed for continuous duty gas compression applications including gas lift, gas gathering, and wellhead gas compression. Ratings range from 317 bkW (425 bhp) at 1800 rpm for rich burn configurations. The engine meets EPA NSPS Site Compliant standards when paired with Caterpillar supplied AFRC and customer supplied aftertreatment.
Industrial Power Generation
Industrial variants offer ratings from 190 bkW (255 bhp) to 317 bkW (425 bhp) at 1800 rpm and 249 bkW (332 bhp) at 1500 rpm. These units are NSPS site compliant capable with customer-supplied aftertreatment. Some ratings include standard emission settings available for export only.
Flywheel and Coupling Interface
The engine utilizes a SAE No. 0 flywheel and SAE No. 0 flywheel housing. The flywheel contains 136 teeth and rotates counterclockwise when viewed from the flywheel end. This standard interface allows for direct mounting of compression drives or generator sets.
Power Take-Off (PTO) Options
Factory-installed PTO options include auxiliary drive pulleys, enclosed clutch and clutch support, front stub shaft, and flywheel stub shaft. Pulley removal kits are available as optional equipment. These configurations support direct mechanical drive applications.
Cooling System Configurations
Standard cooling includes a jacket water pump, aftercooler water pump, and aftercooler core with a 54.9 l (14.5 gal US) capacity. Optional cooling upgrades include radiators, expansion tanks, and heat exchangers. Non-sparking blower fans and fan drives are available for customer-supplied radiators.
Fuel and Ignition Systems
Standard equipment includes a Cat Electronic Ignition System (EIS) with detonation sensitive timing and a natural gas carburetor. Optional ignition systems include CSA ignition and low energy fuel carburetors. Dual gas regulators and propane/natural gas valve and jet kits are available for specific fuel types.
Air Inlet and Filtration
The standard air inlet system features a single element air cleaner with a service indicator. Optional air inlet components include two-stage air cleaners, precleaners, air inlet adapters, and rain caps. These options support operation in dusty or harsh environments.
Lubrication and Maintenance
The engine features a deep sump oil pan with a 147.63 l (39 gal US) refill capacity. Standard oil change intervals are 750 hours. Optional lube system components include auxiliary oil reservoirs and specific lubricating oils. The crankcase breather is top mounted.
Exhaust System Components
Standard exhaust includes watercooled exhaust manifolds and a dry exhaust elbow. Optional exhaust components include flexible fittings, elbows, flanges, rain caps, and mufflers. Exhaust maniflers with instrument holes at each port are available as an option.
Mounting and Vibration Isolation
Standard mounting consists of engine supports. Vibration isolators are available as optional equipment to reduce transmission of engine vibrations. The engine weight is 4500 kg (9921 lb) dry for the compression variant and 2245 kg (4950 lb) net dry for the industrial variant.
All G3408C assemblies by section
Every catalogued assembly group for the Caterpillar G3408C. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Air Inlet And Exhaust System
7e9632 Air Cleaner Gp
| 7E***32 | Air Cleaner Group | 1 |
1256529 Air Cleaner Gp
| 12***29 | Air Cleaner Group | 1 |
1245623 Bypass Gp-Exhaust
| 12***23 | Bypass Group-Exhaust | 1 |
1453251 Bypass Gp-Exhaust
| 14***51 | Bypass Group-Exhaust | 1 |
4p2587 Bypass Gp-Exhaust
| 4P***87 | Bypass Group-Exhaust | 1 |
1221158 Bypass Gp-Exhaust
| 12***58 | Bypass Group-Exhaust | 1 |
7w0489 Cartridge Gp-Turbocharger
| 7W***89 | Cartridge Group-Turbocharger | 1 |
2w7848 Fitting Gp-Exhaust
| 2W***48 | Fitting Group-Exhaust | 1 |
4p3449 Lines Gp-Air
| 4P***49 | Lines Group-Air | 1 |
1054663 Manifold Gp-Water Cooled Exhaust
| 10***63 | Manifold Group-Exhaust | 1 |
1257057 Mounting Gp-Air Cleaner
| 12***57 | Mounting Group-Air Cleaner | 1 |
1418965 Turbocharger Gp
| 14***65 | Turbocharger Group | 1 |
| 2N***66 | Locknut; (3/8-16-Thd)(High Temperature) | 4 |
| 4W***37 | Turbocharger Group | 1 |
4w7637 Turbocharger Gp
| 4W***37 | Turbocharger Group | 1 |
4w8052 Turbocharger Gp
| 2N***66 | Locknut; (3/8-16-Thd)(High Temperature) | 4 |
| 4W***37 | Turbocharger Group | 1 |
| 4W***52 | Turbocharger Group | 1 |
Basic Engine
4n1092 Balancer Gp
| 4N***92 | Balancer Group | 1 |
4p7333 Camshaft Gp-Single
| 4P***33 | Camshaft Group; Camshaft Gp-Single | 1 |
1254251 Camshaft Gp-Single
| 12***51 | Camshaft Group | 1 |
4n1960 Cover Gp-Cylinder Block
| 4N***60 | Cover Group-Cylinder Block | 1 |
4w6732 Cover Gp-Rear
| 4W***32 | Cover Group-Flywheel Housing | 1 |
1077528 Cover Gp-Front Structure
| 10***28 | Cover Group-Front Housing; Cover Gp-Front Structure | 1 |
4w1544 Cover Gp-Oil Pan
| 4W***44 | Cover Group-Lower Structure | 1 |
1247655 Cover Gp-Valve Mechanism
| 12***55 | Cover Group-Valve Mechanism | 1 |
1247656 Cover Gp-Valve Mechanism
| 12***56 | Cover Group-Valve Mechanism | 1 |
1w5009 Crankshaft As*R
| 1W***09 | Crankshaft As | 1 |
1w5010 Crankshaft Gp
| 1W***10 | Crankshaft Group; Crankshaft Group | 1 |
1179510 Cylinder Block As
| 11***10 | Cylinder Block As | 1 |
1222245 Cylinder Block As
| 12***45 | Cylinder Block As | 1 |
1103779 Cylinder Block As
| 11***79 | Cylinder Block As | 1 |
1179509 Cylinder Block As
| 11***09 | Cylinder Block As | 1 |
1103778 Cylinder Block Gp
| 11***78 | Cylinder Block Group | 1 |
1179511 Cylinder Block Gp
| 11***11 | Cylinder Block Group | 1 |
1055430 Cylinder Block Gp
| 10***30 | Cylinder Block Group | 1 |
1247507 Cylinder Block Gp
| 12***07 | Cylinder Block Group | 1 |
1247512 Cylinder Head As
| 12***12 | Cylinder Head As | 1 |
1237336 Cylinder Head As
| 12***36 | Cylinder Head As | 1 |
1511334 Cylinder Head As
| 15***34 | Cylinder Head As | 1 |
1237337 Cylinder Head Gp
| 12***37 | Cylinder Head Group | 1 |
1267577 Cylinder Head Gp
| 12***77 | Cylinder Head Group | 1 |
1247510 Cylinder Head Gp
| 12***10 | Cylinder Head Group | 1 |
1247511 Cylinder Head Gp*R
| 12***11 | Cylinder Head Group | 1 |
6n7788 Damper & Pulley Gp
| 6N***88 | Damper & Pulley Group | 1 |
1399028 Damper & Pulley Gp
| 13***28 | Damper & Pulley Group | 1 |
1n3473 Flywheel Gp
| 1N***73 | Flywheel Group | 1 |
7n2840 Gear Gp-Front
| 7N***40 | Gear Group-Front; Front Timing Gear Group | 1 |
4n3825 Gear Gp-Rear
| 4N***25 | Gear Group-Rear; Rear Timing Gear Group | 1 |
1246646 Guard Gp-Damper
| 12***46 | Guard Group-Damper | 1 |
4w6115 Housing Gp-Flywheel
| 4W***15 | Housing Group-Flywheel | 1 |
4n5226 Housing Gp-Front
| 4N***26 | Housing Group-Front; Front Housing Group | 1 |
1106230 Lifting Gp
| 11***30 | Lifting Group-Engine | 1 |
4w1540 Pan Gp-Oil
| 4W***40 | Pan Group-Oil; -Engine | 1 |
1058316 Piston & Rod Gp-9.7 : 1 Ratio
| 10***16 | Piston & Rod Group | 1 |
1333837 Piston & Rod Gp-9.7 : 1 Ratio
| 13***37 | Piston & Rod Group | 1 |
1358583 Pulley Gp-Crankshaft
| 13***83 | Pulley Group-Crankshaft | 1 |
1238974 Rocker Arm Gp
| 12***74 | Rocker Arm Group | 1 |
1245722 Support Gp-Engine
| 12***22 | Support Group-Engine | 1 |
8n9338 Support Gp-Engine
| 8N***38 | Support Group-Engine; Support Group-Front Engine | 1 |
1245754 Support Gp-Engine
| 12***54 | Support Group-Engine | 1 |
2w9183 Support Gp-Engine-Front
| 2W***83 | Support Group-Engine; -Front | 1 |
6i0244 Valve Mechanism Gp
| 6I***44 | Valve Mechanism Group | 1 |
Cooling System
2w1457 Aftercooler Gp-Raw Water
| 2W***57 | Aftercooler Group-Raw Water; -Sea Air | 1 |
2w2136 Aftercooler Gp-Raw Water
| 2W***36 | Aftercooler Group-Raw Water; -Sea Air | 1 |
6i4390 Aftercooler Gp-Treated Water
| 6I***90 | Aftercooler Group-Treated Water | 1 |
7w2206 Cooler Gp-Engine Oil
| 7W***06 | Cooler Group-Engine Oil | 1 |
1245797 Cover Gp-Jacket Water Outlet
| 12***97 | Cover Group-Water Outlet | 1 |
6n0671 Filler & Cap Gp
| 6N***71 | Filler & Cap Group; -Radiator-Coolant | 1 |
4n7414 Lines Gp-Water
| 4N***14 | Lines Group-Water; Water Lines Group-By-Pass | 1 |
7w1619 Lines Gp-Water-Part 1 Of 2
| 7W***19 | Lines Group-Water | 1 |
4p5943 Lines Gp-Water
| 4P***43 | Lines Group-Water | 1 |
1253403 Lines Gp-Water
| 12***03 | Lines Group-Water | 1 |
7w1619 Lines Gp-Water-Part 2 Of 2
| 7W***19 | Lines Group-Water | 1 |
1116835 Lines Gp-Water
| 11***35 | Lines Group-Water; -Turbocharger Cooling | 1 |
1259758 Lines Gp-Water-Part 2 Of 2
| 12***58 | Lines Group-Water | 1 |
1259758 Lines Gp-Water-Part 1 Of 2
| 12***58 | Lines Group-Water | 1 |
1245794 Lines Gp-Water
| 12***94 | Lines Group-Water | 1 |
1248547 Lines Gp-Water
| 12***47 | Lines Group-Water | 1 |
1371338 Pump Gp-Water*R
| 13***38 | Pump Group-Water | 1 |
1020457 Pump Gp-Water
| 10***57 | Pump Group-Water | 1 |
1050197 Pump Gp-Water
| 10***97 | Pump Group-Water | 1 |
1341486 Pump Gp-Water
| 13***86 | Pump Group-Water | 1 |
9y4013 Tank Gp-Expansion-Part 2 Of 2
| 9Y***13 | Tank Group-Expansion | 1 |
9y4013 Tank Gp-Expansion-Part 1 Of 2
| 9Y***13 | Tank Group-Expansion | 1 |
Electrical And Starting System
1388356 Wiring Gp-Shutoff
| 13***56 | Box Group-Control; -Eis | 1 |
1081674 Junction Box Gp
| 10***74 | Box Group-Control; (Eis) | 1 |
1426210 Wiring Gp-Engine
| 14***10 | Box Group-Control; -Eis | 1 |
1388357 Wiring Gp
| 13***57 | Box Group-Control; -Eis | 1 |
1426213 Wiring Gp-Engine
| 14***13 | Box Group-Control; -Eis | 1 |
1282500 Control Gp-Engine Monitoring
| 12***00 | Control Group-Engine Electronic | 1 |
1110903 Control Gp-Electronic
| 11***03 | Control Group-Engine Electronic | 1 |
1248680 Fastener Gp-Part 2 Of 2
| 12***80 | Fastener Group-Wiring Harness | 1 |
1248680 Fastener Gp-Part 1 Of 2
| 12***80 | Fastener Group-Wiring Harness | 1 |
1461851 Harness As-Wiring
| 14***51 | Harness As-Engine; -Gas Shutoff Valve | 1 |
1461855 Harness As-Wiring
| 14***63 | Plug As-Connecting | 1 |
| 14***55 | Harness As-Solenoid; -Electric Start | 1 |
1461854 Harness As-Wiring
| 10***07 | Kit-Connecting Plug; (2-Pin)(Electronic Control) | 1 |
| 14***54 | Harness As-Solenoid; -Air Start | 1 |
| 3E***62 | Wedge-Plug Lock; (2-Pin) | 1 |
1461856 Harness As-Wiring
| 14***62 | Plug As-Connecting | 1 |
| 14***56 | Harness As-Wiring; -Governor | 1 |
1461857 Harness As-Wiring
| 14***62 | Plug As-Connecting | 1 |
| 14***57 | Harness As-Wiring; -Governor | 1 |
| 3E***02 | Plug As-Connector | 1 |
1461849 Harness As-Wiring
| 11***72 | Plug As-Connector; (10-Pin) | 1 |
| 14***49 | Harness As-Wiring; (Interconnect) | 1 |
| 3E***67 | Ring-Retaining | 1 |
1248611 Ignition Gp-Gas Engine
| 12***11 | Ignition Group-Gas Engine | 1 |
1426208 Ignition Gp
| 14***08 | Ignition Group-Gas Engine | 1 |
1447161 Ignition Gp
| 14***61 | Ignition Group-Gas Engine | 1 |
1527204 Sensor & Mtg Gp
| 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 |
| 11***27 | Plate-Mounting | 1 |
1081655 Sensor & Mounting Gp
| 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 |
1355014 Control Gp-Engine Monitoring
| 13***14 | Sensor Group-Pressure; (Inlet Manifold Air) | 1 |
3e1854 Control Gp-Electronic
| 3E***54 | Sensor Group-Pressure | 1 |
1355015 Sensor Gp-Speed
| 13***15 | Sensor Group-Speed | 1 |
7w3355 Magnetic Pickup Gp
| 7W***55 | Sensor Group-Speed; -Engine Timing | 1 |
1029029 Sensor Gp-Speed
| 10***29 | Sensor Group-Speed; -Timing-Engine Speed | 1 |
1505136 Magnetic Pickup Gp
| 15***36 | Sensor Group-Speed | 1 |
1228070 Transformer Gp
| 12***70 | Transformer Group-Ignition | 1 |
1240749 Transformer Gp
| 12***49 | Transformer Group-Ignition | 1 |
1313277 Transformer Gp
| 13***77 | Transformer Group-Ignition | 1 |
1298802 Transformer Gp
| 12***02 | Transformer Group-Ignition | 1 |
1248681 Wiring Gp-Engine
| 12***81 | Wiring Group-Engine | 1 |
Engine Arrangement
1267477 Engine Ar-Part 2 Of 2
| 10***57 | Pump Group-Water | 1 |
| 10***16 | Piston & Rod Group | 8 |
| 11***30 | Lifting Group-Engine | 1 |
1267477 Engine Ar-Part 1 Of 2
| 10***28 | Cover Group-Front Housing; Cover Gp-Front Structure | 1 |
| 10***97 | Drive Group-Governor | 1 |
| 11***78 | Cylinder Block Group | 1 |
Fuel System
4p4716 Filter Gp-Fuel
| 4P***16 | Filter Group-Fuel | 1 |
| 4P***19 | Filter Element-Fuel; (Gas) | 1 |
9y0830 Carburetor Gp
| 9Y***30 | Carburetor Group | 1 |
1305699 Carburetor Gp
| 13***99 | Carburetor Group | 1 |
1256772 Carburetor Gp
| 12***72 | Carburetor Group | 1 |
1252109 Control Gp-Carburetor
| 12***09 | Control Group-Carburetor | 1 |
1277506 Coupling Gp-Flexible
| 12***06 | Coupling Group-Flexible | 1 |
1077897 Drive Gp-Governor
| 10***97 | Drive Group-Governor | 1 |
1078515 Drive Gp-Governor
| 10***15 | Drive Group-Governor | 1 |
7c8111 Regulator Gp-Gas Pressure-Part 1 Of 2
| 7C***11 | Regulator Group-Gas Pressure | 1 |
7c8111 Regulator Gp-Gas Pressure-Part 2 Of 2
| 7C***11 | Regulator Group-Gas Pressure | 1 |
1256692 Regulator Gp
| 12***92 | Regulator Group-Gas Pressure | 1 |
1046775 Regulator Gp-Gas Pressure
| 10***75 | Regulator Group-Gas Pressure | 1 |
Generators
5n1713 Coupling Gp-Generator Drive
| 5N***13 | Coupling Group-Generator Drive | 1 |
5n2975 Installation Ar-Generator
| 0S***85 | Bolt; 12.7 mm (1/2") Diameter X 38.1 mm (1 1/2") Length Generator To Engine | 16 |
| 2M***49 | Washer-Retainer To Fan Bracket Assembly | 16 |
| 5N***13 | Coupling Group-Generator Drive | 1 |
Lubrication System
2n8220 Breather Gp
| 2N***20 | Breather Group; Breather Gp-Crankcase | 1 |
4n2481 Fastener Gp-Oil Pump Mounting
| 4N***81 | Fastener Group-Oil Pump Mounting; Oil Pump Mounting Fastener Group | 1 |
6n0936 Filter Gp-Oil
| 6N***36 | Filter Group-Engine Oil | 1 |
1274663 Fumes Disposal Gp
| 12***89 | Adapter As-Line | 1 |
| 12***63 | Fumes Disposal Group | 1 |
7c5154 Fumes Disposal Gp
| 7C***54 | Fumes Disposal Group | 1 |
7w4264 Gauge Gp-Oil Level (Dipstick)
| 7W***64 | Gauge Group-Oil Level (Dipstick) | 1 |
4w1548 Gauge Gp-Oil Level (Dipstick)
| 4W***48 | Gauge Group-Oil Level (Dipstick); -Engine | 1 |
1267480 Lines Gp-Engine Oil
| 12***80 | Lines Group-Engine Oil | 1 |
4n8734 Pump Gp-Engine Oil*R
| 4N***34 | Pump Group-Engine Oil; Engine Oil Pump Group | 1 |
Operator Station
1081654 Mounting Gp-Control
| 10***54 | Mounting Group-Control Panel | 1 |
1461852 Gauge Gp-Water Level
| 14***52 | Switch Group-Coolant Level | 1 |
7e3157 Tachometer Gp-Electric
| 7E***57 | Tachometer Group-Electric | 1 |
Service Equipment And Supplies
Name Plates & Films
| 3L***26 | Plate-Information; (Compression Ratio)(Install On Lh Side Of Block) | 1 |
| 3N***69 | Tag-Instruction; (Engine Prestart)(English And Spanish) | 1 |
| 3N***90 | Plate Serial Number; On R.H. Rear Bank Of Cylinder Block As Viewed From Rear Of Engine | 1 |
G3408C serial number reference
The PIN plate is typically located on the right-hand side of the engine block, near the fuel injection pump or on the valve cover. The prefix consists of the first three alphanumeric characters of the serial number, which identify the engine model and manufacturing origin. Verify the specific configuration (industrial vs. generator set) using the prefix, as both variants share the G3408C model designation but have different serial ranges.
| Prefix | Identifies | Notes |
|---|---|---|
| BAZ | G3408C GEN SET ENGINE | Prefix BAZ corresponds to the G3408C generator set engine configuration. This prefix is distinct from the industrial variant and is used for generator applications. |
| 50Y | G3408C INDUSTRIAL ENGINE | Prefix 50Y corresponds to the G3408C industrial engine configuration. This prefix is specific to the industrial application and is distinct from the generator set variant. |
| 68D | G3408C GEN SET ENGINE | Prefix 68D corresponds to the G3408C generator set engine configuration. This prefix is used for generator applications and is distinct from the industrial variant. |
Frequently asked questions
What is the engine type and displacement?
V-8, 18-liter (1099 in³) natural gas industrial engine.
What is the dry operating weight?
4500 kg (9921 lb).
What engine replaced the G3408C?
The G3408LE (Lean Burn) and subsequent G3500 series engines.
What G3408C owners discuss
What are the key powertrain specifications and emissions compliance status for the Caterpillar G3408C industrial engine?
The G3408C is a gas compression engine with a maximum rating of 425 BHP (317 bkW) at a rated speed of 1800 rpm. It features a compression ratio of 8.5:1, turbocharged-aftercooled aspiration, and a 65-degree V-8 configuration. The engine meets U.S. EPA Spark Ignited Stationary NSPS Emissions for 2007/08. It is site-compliant capable with Caterpillar-supplied AFRC and customer-supplied aftertreatment, or available for non-regulated areas. The dry weight is 9921 lb (4500 kg). Displacement is 1099 in³ (18 l). Bore is 5.4 in (137 mm) and stroke is 6 in (152 mm). Flywheel and housing are SAE No. 0 with 136 teeth. Rotation from the flywheel end is counterclockwise. Dimensions are 69.1 in (1756 mm) in length, 61.5 in (1563 mm) in width, and 69.2 in (1758 mm) in height. Cooling system capacity is 14.5 gal (US) (54.9 l). Lube oil refill is 39 gal (US) (147.63 l). Oil change interval is 750 hours. Ignition system is Cat EIS. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of specs from the G3408C product page and Western States Cat summary; no conflicting data found for this specific model designation.
What are the common operational behaviors and maintenance requirements for the G3408C's electronic ignition and fuel systems?
The Cat Electronic Ignition System (EIS) uses detonation-sensitive timing to protect against detonation damage. It provides higher voltage and longer spark duration for easier starts, fewer misfires, and smoother operation. Diagnostic codes help pinpoint cylinder and component issues. Spark plug maintenance codes identify spark plug condition. The fuel system requires a gas pressure regulator with 1.5 to 5 psi gas supply. It uses a natural gas carburetor. Standard equipment includes a single-element air cleaner with a service indicator. Optional equipment includes a two-stage air cleaner, dual gas regulator, and fuel filter. The engine is designed to burn a wide spectrum of gaseous fuels. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of ignition and fuel system details from the G3408C product page; no conflicting data found.
What are the typical wear patterns or known issues associated with the G3408C's cooling and lubrication systems?
The G3408C features a deep sump oil pan with larger capacity to support normal 750-hour oil change intervals. Side covers on the block allow for inspection of internal components. The lube system includes a crankcase breather (top mounted), oil cooler, oil filter (RH), oil pan (deep sump), oil filler (RH in valve cover), and RH dipstick. The cooling system includes thermostats and housing, jacket water pump, aftercooler water pump, and aftercooler core. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of lube and cooling system details from the G3408C product page; no conflicting data found.
How does the G3408C's design contribute to its durability and emissions performance compared to older models?
The G3408C is built on the industry-standard G3400 platform, bringing maximum uptime and low operating cost. It features improved reliability and durability, robust diesel strength design, and broad operating speed range. The lean-burn engine technology operates with large amounts of excess air, which absorbs heat during combustion, reducing combustion temperature and pressure, greatly reducing levels of NOx. This design also provides longer component life and excellent fuel consumption. The engine meets U.S. EPA Spark Ignited Stationary NSPS Emissions for 2007/08. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of design and emissions details from the G3408C product page; no conflicting data found.
What are the standard and optional equipment configurations for the G3408C's air inlet and exhaust systems?
Standard air inlet system includes a single-element air cleaner with a service indicator. Standard exhaust system includes watercooled exhaust manifolds and a dry exhaust elbow. Optional air inlet equipment includes a two-stage air cleaner, air inlet adapter, precleaner, and air cleaner rain cap. Optional exhaust equipment includes flexible fittings, elbows, flanges, rain caps, mufflers, and an exhaust manifold with instrument holes at each port. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of air and exhaust equipment details from the G3408C product page; no conflicting data found.
What are the typical mounting and protection system features for the G3408C?
The G3408C includes engine supports as standard mounting. Protection system features include detonation sensitive timing control and a shutoff. Optional mounting equipment includes vibration isolators. Optional protection equipment includes gas valves and a status control box interconnect wiring harness. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of mounting and protection details from the G3408C product page; no conflicting data found.
What should be checked when buying a used G3408C engine?
When buying a used G3408C, check the spark plug condition using the maintenance codes, inspect the gas pressure regulator and carburetor for wear, verify the integrity of the deep sump oil pan and side covers for leaks or damage, check the cooling system components including thermostats, jacket water pump, aftercooler water pump, and aftercooler core, inspect the air cleaner and service indicator, examine the exhaust manifolds and dry exhaust elbow for cracks or damage, verify the flywheel and housing condition, check the ignition system components including the Cat EIS and wiring harness, inspect the lube system components including the crankcase breather, oil cooler, oil filter, oil filler, and dipstick, check the mounting system including engine supports and optional vibration isolators, verify the protection system including detonation sensitive timing control and shutoff, check the optional equipment if equipped including gas valves and status control box interconnect wiring harness, and verify the engine's compliance with U.S. EPA Spark Ignited Stationary NSPS Emissions for 2007/08. Source: Caterpillar G3408C Gas Compression Engines spec sheet and Western States Cat product page. Verification note: Confirmed via direct extraction of inspection points from the G3408C product page; no conflicting data found.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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