Caterpillar 3150
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar 3150 is a legacy stationary industrial engine, not a mobile machine: a V-8, four-stroke, naturally aspirated diesel run by a mechanical governor and an in-line (jerk-type) injection pump, with no electronic controls of any kind. Displacement is 9.4 L (573 cu in) from a 114 mm x 114 mm (4.50 in x 4.50 in) bore and stroke, at a 17:1 compression ratio. It belongs to Caterpillar's 3145/3150/3160 industrial and generator-set ("electric set") engine family from the 1960s-70s, built on the same basic block as the 1145/1150/1160 truck engines of that generation. Two serial prefixes cover this model: one built specifically for the electric-set/generator-set configuration, the other shared across gen-set, industrial, and truck applications, so the full serial number - not just the prefix - confirms which configuration a given unit actually is. Bare-engine and packaged-set weights are not consistently documented across surviving factory literature; treat any weight figure as unverified until checked against the data plate or the packager's own spec sheet. Caterpillar replaced this family with the 3208 in the mid-1970s.
Within the family, the 3145, 3150, and 3160 share the same block and injection-pump architecture tuned to different displacement and output levels, and the electric-set package itself went through at least two documented running changes mid-production - a control-panel arrangement update and a cooling-system arrangement update - each tied to a generator serial breakpoint rather than a full model change. The 3208 that succeeded it kept a similar external look and mounting footprint but moved to a V-type injection pump, a stronger crankshaft, and a reworked cooling circuit, so fuel-system parts do not cross over despite the family resemblance. In today's market, the 3150 survives mainly in remote or legacy standby and prime-power installations, where its fully mechanical, ECM-free design is valued precisely because it needs no electronics to run or diagnose. Parts increasingly come from vintage-industrial-engine specialists and NOS stock rather than a live Cat parts counter, so buyers and owners should expect longer lead times, confirm the serial prefix before buying, and check for the fuel-in-oil symptom that is this fuel system's most common failure before putting a unit back into service.
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 3150 specifications
Engine
| Engine family / lineage | V-8 diesel in the 3145/3150/3160 industrial and generator-set (electric set) engine family, built alongside the 1145/1150/1160 truck engines of the same generation. This family was superseded by the 3208 in the mid-1970s. |
| Configuration | V-8, four-stroke-cycle diesel, naturally aspirated, in-line (jerk-type) fuel injection pump, mechanical governor. |
| Bore x Stroke | 114 mm x 114 mm (4.50 in x 4.50 in) |
| Displacement | 9.4 L (573 cu in) |
| Compression ratio | 17:1 |
| Power rating | No single generator-set/industrial nameplate rating is consistently documented for the 3150 across independent sources. For family context only: the sibling 1150 truck version of this block was rated 200 hp at 3000 rpm, and the larger-displacement 3160 family member was rated around 210 hp at 2800 rpm in marine duty. Confirm the exact rating for a given 3150 serial range from its data plate. |
| Emissions tier | Not applicable. Design predates emissions-tier certification (1960s-1970s mechanical diesel). |
Weights
| Engine net dry weight | Not consistently documented across independent sources for this model. Verify against the factory specifications manual or engine data plate. |
| Shipping weight | Not published in available sources for this model. |
| Ground pressure | Not applicable. This is a stationary industrial/generator-set engine, not a wheeled or tracked machine. |
Dimensions
| Transport length/width/height | Not published in available sources for the 3150 long block or electric-set package. |
| Wheelbase / track gauge | Not applicable to this engine type. |
| Ground clearance | Not applicable to this engine type. |
Performance
| Travel speed | Not applicable. Stationary industrial/generator-set engine with no travel function. |
| Rated/governed speed | Not consistently documented for the 3150 specifically. A related family member (3145) is documented at 2400 rpm full load with 2630 rpm high idle; treat as family background only, not a confirmed 3150 figure. |
| Gradeability | Not applicable to this engine type. |
Service capacities (summary)
| Fuel tank | Not applicable/not published. Fuel tank sizing depends on the host machine or generator skid, not the bare engine. |
| Engine oil | Not documented in available sources for this model. |
| Cooling system | Not documented in available sources for this model. |
| Hydraulic system | Not applicable. This is a diesel engine/generator power unit, not a hydraulic machine. |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
3150 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | approx. 12.3 L (13.0 US qt) - varies slightly by oil pan/sump option fitted to the electric-set package | This is a 1960s/70s vintage V-8 industrial diesel from the 3100 series, built before Caterpillar's modern branded oil line existed. Period-correct fill is a straight-grade diesel engine oil meeting API CD/CC service, per Caterpillar's own diesel engine oil spec of that generation. Recommendation steps down by climate: SAE 30 for temperate to hot ambient, SAE 10W or 10W-30 for cold-weather starting. Confirm actual grade against the nameplate/serial-specific OMM before filling, since later reprints may reference newer equivalents. |
| Cooling system | approx. 37.9 L (40.0 US qt) engine-side circuit - total system capacity depends on the radiator or heat exchanger the generator-set packager fitted, so treat this as a baseline and verify against the actual cooling package | Pressurized, thermostat-controlled, pump-circulated system with an expansion tank above or beside the radiator core. Fill is a roughly 1:1 mixture of ethylene-glycol antifreeze and clean water with a Caterpillar-spec corrosion/cavitation inhibitor, consistent with the engine's era cooling-system service literature (predates Cat's modern extended-life coolant line). Check inhibitor concentration at each service interval on this vintage of engine, since the original chemistry required more frequent top-up than later formulations. |
| Fuel tank | not a fixed engine-side figure - bare electric-set engines of this line were shipped without a standardized tank; capacity was set by whichever generator-set packager or sub-base builder fitted the day tank | No single OMM fuel-tank spec applies across this configuration. Use clean, water-free diesel fuel per the engine's fuel-system and injection-pump requirements; confirm tank size against the nameplate of the actual packaged set. |
| Grease (fittings) | spec only - no fill volume, applied at external lube points (water pump, linkage, fan/idler bearings) per the lubrication chart | Multipurpose NLGI 2 lithium-base chassis grease, consistent with Caterpillar's general external-lubrication guidance for 3100-series industrial/electric-set engines of this era. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar 3150 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 3,000 h |
|
Servicing the 3150 beyond the schedule
Predictive Maintenance & Fluid Analysis
No ECM and no fault codes, so fluid condition and gauge trend are the real diagnostics here. Watch the dipstick for a fuel smell or rising level, the recurring failure traced to worn injector tips, a bad copper washer, or a failed pump seal. Track coolant inhibitor concentration closely, since this era's chemistry needs more frequent monitoring than modern coolant. Log oil pressure and water temperature readings run to run; trending them by hand is the only predictive tool this analog panel offers.
Corrective & Common Repairs
Fuel-in-oil from worn injector tips, a bad copper washer, or a failed pump seal is the top corrective repair; check the dipstick for fuel smell first. A hunting governor or unresponsive rack usually means stuck pump internals, not external linkage; hand-move the rack at the pump cover to tell them apart. Overheating on a packaged set traces to a coolant leak, dirty radiator fins, a worn belt, or blocked enclosure airflow more often than the engine. Gauge senders, starter wear, and charging faults are the electrical items that actually fail.
Overhaul & Rebuild Points
This engine's injection pump and fuel system do not interchange with the later 3208 despite a similar look, so source overhaul parts against its own serial prefix, not the newer catalog. Top-end rework resets pistons, liners, rings, and main and rod bearings on the naturally aspirated block, with no turbocharger or ECM tuning to complicate the job. Governor and injection pump internals need a specialist injection-pump shop, not a general rebuild bench. Recheck the mechanical overspeed trip and the vibration isolators between inner base and skid before returning the set to service.
Seasonal & Environment Servicing
Standby sets idle for long stretches need the overspeed trip and governor linkage exercised, since mechanical parts stick from disuse faster than electronic ones. Indoor engine-room installs depend on the cooling arrangement, engine-mounted radiator versus remote heat exchanger, giving the radiator and generator coupling clear, non-recirculating air, not just a healthy core. Cold-climate starts on this mechanically governed engine rely on battery condition and starting aids, not any electronic strategy; test cranking amps before winter layup. Recheck coolant inhibitor concentration each season, since this era's chemistry ages faster than modern coolant.
3150 common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 8S-4197 | Transfer-- Filter Instructions | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
3150 attachments & work tools
Control panel arrangement
Factory package documented with two control panel arrangements, Type 1 and Type 2, the newer one introduced partway through the production run at a specific generator serial breakpoint. Panel carries standard engine/generator instrumentation - voltage, frequency, oil pressure, coolant temperature, and shutdown protection - mounted on the set itself rather than remote.
Cooling system arrangement
Two cooling system groups documented for this set, Type 1 and Type 2, again split by a generator serial breakpoint mid-production. Reflects the standard industrial choice between engine-mounted radiator-and-fan cooling and a remote-radiator or heat-exchanger arrangement for indoor engine-room installs; verify which arrangement applies by serial number before ordering cooling parts.
Engine enclosure and exhaust
A factory sheet-metal engine enclosure (Type 2) is documented for this set, sized to pair with a matching muffler/exhaust silencer group. This is a weather, noise, and access shield fitted over the engine, not a full sound-attenuated canopy.
Mounting and vibration isolation
Engine and generator end sit on a common inner base, which sets onto the outer skid base through resilient rubber or spring vibration isolators - standard practice for this class of industrial set to limit vibration reaching the mounting pad. Ships as a stationary skid-mounted package; no wheeled/trailer arrangement is documented for this model.
Governor and speed control
Engine of this vintage and class runs on a mechanical flyweight-type governor holding fixed speed for 50 Hz or 60 Hz generator duty. No factory electronic governor upgrade is documented specifically for this model - later Cat generator engines moved to electronic governing, but that is not confirmed for this set.
Paralleling and multi-set switchgear
No model-specific paralleling switchgear package is documented for this set. Where multiple sets of this class fed one bus, paralleling was handled through external switchgear rather than an integrated factory kit, consistent with common practice for industrial sets of this era.
All 3150 assemblies by section
Every catalogued assembly group for the Caterpillar 3150. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Diesel Engine
2n905 Air Cleaner Group
| 2N***05 | Air Cleaner Group | 1 |
Air System (2n211 N/S)
| 2N***11 | Air System; Air System Group | 1 |
2n7759 Alternator Assembly
| 2N***59 | Alternator As | 1 |
8l5410 Alternator Assembly--12 Volt, 35 Ampere
| 8L***10 | Alternator Assembly | 1 |
3n1382 Alternator Assembly--12 Volt--Field Installation
| 2N***80 | Harness As-Wiring; (Alternator) | 1 |
| 2N***96 | Alternator Assembly | 1 |
| 2N***78 | Regulator Assembly | 1 |
2n6396 Alternator Assembly--12 Volt, 35 Ampere--Type 2
| 2N***96 | Alternator Assembly | 1 |
3n1384 Alternator Assembly--12 Volt--Field Installation
| 1H***87 | Screw-Machine; (10-24x0.438-In) | 3 |
| 2N***80 | Harness As-Wiring; (Alternator) | 1 |
| 2N***78 | Regulator Assembly | 1 |
2n6396 Alternator Assembly--12 Volt, 35 Ampere--Type 1
| 2N***96 | Alternator Assembly | 1 |
Base (2n2101 N/S)
2n3470 Battery Installation Group
| 2N***70 | Battery Installation Group | 1 |
Blower Fan (2n2895 N/S)
| 2N***95 | Blower Fan | 1 |
1n9970 Air Cleaner Assembly
| 1N***70 | Cleaner As-Air | 1 |
9l8568 Connecting Rod And Piston Group--8 Required
| 9L***68 | Connecting Rod And Piston Group | 1 |
2n2803 Connections Diagram Plate
| 2N***03 | Connections Diagram Plate | 1 |
2n2374 Contactor Group
| 2N***74 | Contactor Group | 1 |
2n3458 Control Panel Assembly--Type 2
| 2N***58 | Control Panel Assembly | 1 |
2n3458 Control Panel Assembly - Type 1
| 2N***58 | Control Panel Assembly | 1 |
Cooling System (2n5752 N/S)-Type 1
| 2N***52 | Cooling System | 1 |
Cooling System (2n5752 N/S)--Type 2
| 2N***52 | Cooling System | 1 |
Cooling System (9l9886 N/S)
| 9L***86 | Cooling System Group | 1 |
Cover And Housing (2n2279 N/S)
| 2N***79 | Cover And Housing | 1 |
Crankshaft Bearing Replacements
| 9L***48 | Bearing--Main (.010 Oversize) | 4 |
| 9L***49 | Bearing--Thrust (.010 Oversize) | 1 |
| 9N***20 | Bearing--Thrust (.020 Undersize) | 1 |
Crankshaft (9l8300 N/S)
| 9L***00 | Crankshaft Group | 1 |
9l9446 Cylinder Block Group
| 9L***46 | Cylinder Block Group | 1 |
9n130 Cylinder Block Group
| 9N***30 | Cylinder Block Group; Cylinder Block Group | 1 |
9l9601 Cylinder Head Group
| 9L***01 | Cylinder Head Group | 1 |
2n2398 Droop Compensation Group
| 2N***98 | Droop Compensation Group | 1 |
Electrical System (2n2309 N/S)--Engine Mounted Components--12 Volt--Part 2 Of 2
| 2N***09 | Electrical System | 1 |
Electrical System (2n2309 N/S)--Engine Mounted Components--12 Volt--Part 1 Of 2
| 2N***09 | Electrical System | 1 |
Electrical System--Generator Mounted Components--12 Volt
2n3592 Engine Enclosure Group--Type 1
| 2N***92 | Engine Enclosure Group | 1 |
2n3592 Engine Enclosure Group--Type 2
| 2N***92 | Engine Enclosure Group | 1 |
8h4681 Primary Fuel Filter Group
| 8H***81 | Filter Group-Primary Fuel; Primary Fuel Filter Group | 1 |
8l6378 Flywheel Group
| 8L***78 | Flywheel; Flywheel Group | 1 |
9l8822 Fuel Filter Group
| 9L***22 | Fuel Filter Group | 1 |
Fuel Pump Housing And Governor (2n2081 N/S)
| 2N***81 | Fuel Pump Housing And Governor | 1 |
Fuel Pump Housing And Governor (2n7723 N/S)
| 2N***23 | Fuel Pump Housing And Governor | 1 |
2n2082 Fuel Pump Housing Group
| 2N***82 | Fuel Pump Housing Group | 1 |
Fuel System (2n2080 N/S)--Part 2 Of 2
| 2N***80 | Fuel System | 1 |
Fuel System (2n2080 N/S)--Part 1 Of 2
| 2N***80 | Fuel System | 1 |
2n7722 Fuel System Group--Part 1 Of 2
| 2N***22 | Fuel System Group | 1 |
2n7722 Fuel System Group--Part 2 Of 2
| 2N***22 | Fuel System Group | 1 |
2n3435 Fuel Tank Group--Type 2
| 2N***35 | Fuel Tank Group | 1 |
2n3435 Fuel Tank Group--Type 1
| 2N***35 | Fuel Tank Group | 1 |
Gasket Kits
| 9L***66 | Engine Overhaul | 0 |
| 9L***68 | Valve Grinding | 0 |
8l6244 Generator Assembly
| 8L***44 | Generator Assembly | 1 |
2n2111 Governor Control Group--Factory Installation
| 2N***11 | Governor Control Group | 1 |
9l7799 Governor Cylinder Group
| 9L***99 | Governor Cylinder Group | 1 |
2n2083 Governor Group--Part 2 Of 2--Type 1
| 2N***83 | Governor Group | 1 |
2n2083 Governor Group--Part 1 Of 2--Type 2
| 2N***83 | Governor Group | 1 |
2n2083 Governor Group--Part 2 Of 2--Type 2
| 2N***83 | Governor Group | 1 |
2n2083 Governor Group--Part 1 Of 2--Type 1
| 2N***83 | Governor Group | 1 |
2n5292 Instrument Panel Cover Group
| 2N***92 | Instrument Panel Cover Group | 1 |
Lubricating System (9l8306 N/S)
| 9L***06 | Lubricating System Group | 1 |
2n2338 Meter Group--220/380-400 Volt-50 Hertz
| 2N***38 | Meter Group | 1 |
2n2337 Meter Group--240/416-480 Volt--60 Hertz
| 2N***37 | Meter Group | 1 |
2n2336 Meter Group--110/190-200 Volt--50 Hertz
| 2N***36 | Meter Group | 1 |
2n2335 Meter Group--120/208-240 Volt--60 Hertz--Type 1
| 2N***35 | Meter Group | 1 |
2n2338 Meter Group--220/380-400 Volt, 50 Hertz--Type 2
| 2N***38 | Meter Group | 1 |
2n2337 Meter Group--240/416-480 Volt, 60 Hertz--Type 2
| 2N***37 | Meter Group | 1 |
2n2335 Meter Group--120/208-240 Volt, 60 Hertz--Type 2
| 2N***35 | Meter Group | 1 |
2n2336 Meter Group--110/190-200 Volt, 50 Hertz--Type 2
| 2N***36 | Meter Group | 1 |
2n1646 Muffler Group
| 2N***46 | Muffler Group | 1 |
Name Plates And Transfers
| 1H***63 | Plate Serial Number | 1 |
| 2N***36 | Plate--Warning And Information | 1 |
| 2N***70 | Transfer--3150 Caterpillar | 2 |
Oil Pan (2n8545 N/S)
| 2N***45 | Oil Pan | 1 |
Oil Pan--Front Sump (8l9780 N/S)
| 8L***80 | Oil Pan; Oil Pan Group | 1 |
Radiator--Rear View
2n3260 Regulator Assembly
| 2N***60 | Regulator Assembly | 1 |
9n1253 Short Block Group--Field Installation
| 9L***65 | Crankshaft Assembly | 1 |
| 9L***07 | Gear | 1 |
| 9L***45 | Bearing (Main); Bearing --Main | 4 |
7l6586 Solenoid Switch Assembly
| 7L***86 | Solenoid As | 1 |
8l5881 Starting Motor Assembly--12 Volt--Part 2 Of 2
| 8L***81 | Starting Motor Assembly | 1 |
8l5881 Starting Motor Assembly--12 Volt--Part 1 Of 2
| 8L***81 | Starting Motor Assembly | 1 |
2s9519 Rack Stop Group
| 2S***19 | Stop Group-Rack | 1 |
9l8790 Crankcase Ventilation Valve Assembly
| 9L***90 | Valve As-Pcv | 1 |
9l8307 Valve Mechanism Group
| 9L***07 | Valve Mechanism Group | 1 |
Wiring Diagram--Engine And Generator--12 Volt System
3150 serial number reference
The engine serial number plate sits on the cylinder block, near the valve cover or the fuel-injection-pump side; the exact side is reported inconsistently across sources, so check both sides if it is not immediately visible. It reads as an 8-character stamp: a 3-letter prefix identifying the model/build configuration, followed by a 5-digit sequential unit number (pad with a leading zero if only 4 digits show). Match the 3-letter prefix against the model's known prefix list first (66P covers gen-set units only; 88V spans gen-set, industrial, and truck-rated units), then use the numeric tail only to place the unit within that run.
| Prefix | Identifies | Notes |
|---|---|---|
| 66P | 3150 gen set engine (electric set) | Dedicated generator-set build of the 3150 V8 diesel. Factory wiring-diagram documentation for the electric set is titled around a 66P00001-and-up serial range, and independent serial-prefix guides list 66P only under the gen-set heading, not industrial or truck. |
| 88V | 3150 engine - shared prefix across gen set, industrial, and truck listings | Same three-character prefix appears under three separate application headings (gen set, industrial engine, and highway truck engine) in the reference guides, unlike most Cat model/prefix pairs which are application-specific. Treat as one prefix block covering multiple 3150 configurations rather than three distinct codes. |
Frequently asked questions
What engine does the Caterpillar 3150 use?
The 3150 designation is the engine itself, not a machine carrying a separate powerplant. It is a V-8, four-stroke, naturally aspirated diesel of 9.4 L (573 cu in) displacement, with 114 mm x 114 mm (4.50 in x 4.50 in) bore and stroke and a 17:1 compression ratio. Fuel delivery is a mechanically governed, in-line (jerk-type) injection pump with no electronic controls. It belongs to Caterpillar's 3145/3150/3160 industrial and generator-set engine family, built alongside the 1145/1150/1160 truck engines of the same generation.
What is the operating weight of the Caterpillar 3150?
Net dry weight for the bare 3150 engine, and total package weight for a complete electric set (generator end, control panel, skid base, and enclosure), are not consistently documented across available factory literature. As a stationary engine it carries no ground-pressure or axle-weight figures the way a mobile machine does. Confirm actual weight against the engine data plate or the specific generator-set packager's spec sheet, since skid base, enclosure, and cooling-package choices all add variable weight beyond the bare engine.
What replaced the Caterpillar 3150?
Caterpillar replaced the 3145/3150/3160 family with the 3208 in the mid-1970s. The 3208 kept a similar block architecture and mounting footprint but switched to a V-type injection pump, fitted a stronger crankshaft, and reworked the cooling circuit. A 3150 and a 3208 look alike at a glance, but the fuel system and several core parts are not interchangeable between them; always confirm parts against the engine's own serial prefix rather than assuming 3208 compatibility.
What 3150 owners discuss
How does the 3150 relate to its 3145/3160 siblings and the 3208 that replaced it, and does that affect parts interchange?
What's the known weak point in the mechanical fuel system, and what does it look like when it fails?
The governor is hunting or the unit won't respond to the rack - how do owners typically chase that down?
What causes overheating on a genset package built around an engine this old?
It has no fault codes - what electrical issues actually show up on these?
What should a buyer check before taking on a used 3150 generator set?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Serial-range & configuration variants
This page covers the Caterpillar 3150. Related factory variants of the same model family:
Need a specific 3150 part?
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