HomeEnginesCaterpillar C18

Caterpillar C18 Engine

The Caterpillar C18 is a 18.1 L 6-cylinder ataac engine rated at 1800 rpm, producing up to 545 kW. It powers generator sets from Caterpillar, including the C18 Diesel Oilfield Generator Set, C18-20' XQ600 and D600 GC. It holds 20.8 L (5.5 gal) of oil and 20.8 L (5.5 gal) of coolant.

Also known as: Caterpillar C18, C18

Part of the Caterpillar C18 engine family — 3 variants share parts & fitment.

18.1 L
Displacement
6
Cylinders
1800 rpm
Rated speed
545 kW
Gross power

Engine specifications

Oil capacity20.8 L
Coolant capacity20.8 L
Displacement18.1 L
Cylinders6
AspirationATAAC
Rated speed1800 rpm
Gross power545 kW

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filterDual element air cleaner200 hr
Fuel filterPrimary fuel filter with integral water separator, Secondary fuel filters200 hr
Oil filterLubricating oil and filter200 hr
BatteryBatteries with rack and cables200 hr
BeltFan and belt guards, Belt200 hr
CoolantCaterpillar Extended Life Coolant3000.0 l
Coolant filter
OilLubricating oil and filter20.8 l
Spark plugSpark Plug

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

6
ItemActionHoursMonthsNotes
Primary air filter elementChange250 hrWhen changing the primary element at 250 operating hours (basis of the without-indicator filter-change comparison)
oilChange500 hr3000 Series service intervals increased to 500 hours as standard (3013C, 3024C, 3054, 3056)
Secondary air filter elementChange750 hrWhen changing the secondary element at 750 operating hours (basis of the without-indicator filter-change comparison)
minor overhaulOther20000 hr3600 engines designed to run 20 000 hours between minor overhauls using No. 2 fuel
major overhaulOther40000 hr3600 engines designed to run 40 000 hours between major overhauls using No. 2 fuel
cylinder liners and pistonsOther80000 hr3600 cylinder liners and pistons designed for 80 000 hours using No. 2 fuel

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

57
TypeItemValueUnitCondition
ClearanceCylinder bore diameter5.4IN
ClearancePiston stroke6.7IN
OtherCombustion air inlet flow rate38.2m3/min
OtherExcitation ceilingadjustable at 3 pointsby configuration
OtherField excitation current0-5Arated; short-circuit 10A max
OtherFrequency range10-100Hz
OtherGross Input Torque (TH55-E70)12 667N•m (9350 lb-ft)
OtherGross Input Torque (TH55-E90)12 677N•m (9350 lb-ft)
OtherMaximum fuel flow from transfer pump to engine69.2G/HR
OtherMaximum transfer pump priming lift without priming pump12.1FT
OtherMaximum uninterrupted fill rate5.0G/MIN
OtherQuadrature droop adjustment range-20 to 20%
OtherRadiator air flow720m3/min
OtherRadiator cooling package design ambient temperature48.9°C (120° F)with 50/50 water/Extended Life Coolant mixture
OtherRadiator cooling package maximum elevation1524m (5000 ft)with 50/50 water/Extended Life Coolant mixture
OtherRegulation accuracy+/-0.25%of the average of the three phases on a linear load, with harmonic distortion less than 5%
OtherStall Torque Ratio (TH55-E70)2.23
OtherStall Torque Ratio (TH55-E90)2.23
OtherStator current measurement range0-1 or 0-5A
OtherTotal cylinder displacement928CU IN
OtherUnder frequency slope0.5 to 3V/Hzadjustable in steps of 0.1 V/Hz
PressureExhaust system backpressure (maximum allowable)10.0kPa
PressureMaximum allowable fuel return line restriction14.8in-HG
PressureMaximum allowable fuel supply line restriction8.0in-HG
PressureMaximum allowable intake restriction with clean element15in-H2O
PressureMaximum allowable intake restriction with dirty element25in-H2O
PressureMaximum allowable system back pressure40in-H2O
PressureMaximum pressure drop from compressor outlet to manifold inlet (or mixer inlet for EGR)4.4in-HG
PressureNormal fuel pressure in a clean system90.1PSI
PressureOil pressure65-69at 600 kW load
PressureRadiator air flow restriction (system)0.12kPa
PressureUnit injector fuel injection pressure1240bar (18 000 psi)
PressureWS255 pump plunger load238,000lb (107,960 kg)
PressureWS273XD pump plunger load275,000lb (124 738 kg)
PressureWS305XD pump plunger load250,000lb (113 398 kg)
ResistanceField winding resistance>4ohms
SpeedFrequency60Hz
SpeedMaximum Input Speed (TH55-E70/TH55-E90 transmissions)1970rpm
SpeedMinimum cranking speed required for start115RPM
SpeedRated Input Speed (TH55-E70/TH55-E90 transmissions)1900rpm
TemperatureAmbient operating temperature-40 to +65°C
TemperatureAmbient temperature65-66°F
TemperatureCoolant temperature189-190°Fat 600 kW load
TemperatureExhaust stack gas temperature531.1deg C
TemperatureLowest ambient start temperature without aids32deg F
TemperatureMax. allowable combustion air inlet temperature49deg C
TemperatureMaximum allowable fuel temperature at engine outlet225deg F
TemperatureMaximum allowable fuel temperature at transfer pump inlet140deg F
TemperatureMaximum allowable jacket water outlet temperature219deg F
TemperatureRadiator DELTA-T38D
TorqueAir compressor SAE "A" hydraulic pump drive maximum torque (374 L/min and 467 L/min compressors)60N•m (44 lb-ft)C7, C9 ACERT
VoltageAlternator voltage sensing0-530VACthree-phase range
VoltageDC voltage27.1V
VoltagePower supply voltage range50-277VAC
VoltageVoltage adjustment range0 to 150% of rated voltage
VoltageVoltage level adjustment+/-5.0%
VoltageVoltage regulation, steady state+/-1.0%

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

FluidGradeStandardAmbientCapacityNotes
Coolant50/50 mixture water/Caterpillar Extended Life Coolantbelow 48°CRadiator cooling packages designed for up to 48.9° C (120° F) ambient; coolant sump refill capacities vary by oil sump/pan (18 L to 106 L service refill with new oil filter change)
CoolantCat DEACDiesel; 3,000 Service Hours or Three Years; annual S·O·SSM Level 2 coolant sampling and analysis
CoolantCat ELCDiesel; 12,000 Service Hours or Six Years; add Cat ELC Extender at 6,000 service hours or one half of service life; annual S·O·SSM Level 2 coolant sampling and analysis
CoolantCat NGECNatural Gas; 16,000 Service Hours or Three Years; use interval that occurs first
Engine oilCat NGEONatural Gas
Engine oilCat Arctic DEO SYN SAE 0W-30-40°C to 30°CEngine Crankcase; Industrial Engines
Engine oilCat DEO SYN SAE 5W-40-30°C to 50°CEngine Crankcase; Industrial Engines
Engine oilCat DEO SAE 10W-30-18°C to 40°CEngine Crankcase; Industrial Engines
Engine oilCat DEO SAE 15W-40-9°C to 50°CEngine Crankcase; Industrial Engines
FuelLCV = 42700 kJ/kgMaK technical data; without engine-driven pumps, tolerance 5%
Fuel35° API gravity at 60°F (16°C)LHV 18,390 Btu/lb (42 780 kJ/kg)Fuel at 85°F (29°C) weighing 7.001 lbs/U.S. gal (838.9 g/liter)
FuelNo. 2 dieselFuel oil of 35° API gravity, LHV 42 780 kJ/kg (18,390 Btu/lb)
FuelNo. 2 diesel fuel35 API, LHV 18,390 Btu/lbwhen used at 29°C (85°F) and weighing 838.9 g/litre (7.001 lbs/U.S. gal.)
FuelNo. 2 fuel3600 engines designed for 80 000 hours on No. 2 fuel; ratings based on API gravity of 35 at 15 C (60 F), LHV of 42 780 kJ/kg used at 29 C (84 F) with a density of 838.9 g/L
GreaseCat Generator Set GreasePart Number 108-8611

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

VoltagePhaseConnectionLeadsNotes
33 Phase Star (6 Wire)Standard connection
3Parallel Star (12 Wire)
3Series Star (12 Wire)

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Parts cataloged across the Caterpillar C18 family

103
Part #DescriptionCategory
106-3973Air filter innerair_filter
151-7737Air Primaryair_filter
189-0202Air Secondaryair_filter
1W-3636Air Secondaryair_filter
1W-3637Air Primaryair_filter
246-5009Airair_filter
246-5010Airair_filter
4N0015Air filter outerair_filter
7C-1571Air Primaryair_filter
8N6309Air filter outerair_filter
9Y-3879Airair_filter
6T1395Alternatoralternator
118-2018V-beltbelt
4N6302V-beltbelt
M-CK3687817PCylinder Kitcylinder_kit
133-5673Fuel/Water Separatorfuel_filter
1R-0749Fuel Secondary - ADVfuel_filter
1R-0762Fuel Secondary - ADVfuel_filter
1R-0770Fuel/Water Separatorfuel_filter
1R-0781Fuel/Water Separator - ADVfuel_filter
1R0749Filter fuelfuel_filter
1R0755Filter fuelfuel_filter
326-1641Axial seal FWSfuel_filter
326-1642Filter water separatorfuel_filter
326-1643Filter water separatorfuel_filter
3S3875Filter fuelfuel_filter
9N3717Filter water separatorfuel_filter
4N1151Gasket oil pangasket
M-4220925Gasket Set - Rear Structuregasket
M-4337629Gasket Set - Rear Structuregasket
M-4351087Gasket Set - Rear Structuregasket
M-4361559Gasket Set - Front Structuregasket
M-4365757Gasket Set - Turbo Installationgasket
M-4452666Gasket Set - Rear Structuregasket
M-4496052Gasket Set - Oil Cooler & Linesgasket
M-4588198Gasket Set - Front Structuregasket
M-4682161Gasket Set - Cylinder Headgasket
M-4685553Gasket Set - Central & Lowergasket
M-4685746Gasket Set - Cylinder Headgasket
M-4687363Gasket Set - Water Pumpgasket
M-4687942Gasket Set - Turbo Installationgasket
M-4690626Gasket Set - Central & Lowergasket
M-4690822Gasket Set - Turbo Installationgasket
M-4690823Gasket Set - Cylinder Headgasket
M-4690878Gasket Set - Cylinder Headgasket
M-4692381Gasket Set - Central & Lowergasket
M-4692382Gasket Set - Fuel Systemgasket
M-4692388Gasket Set - Cylinder Headgasket
M-4701892Gasket Set - Turbo Installationgasket
M-4733264Gasket Set - Rear Structuregasket
M-4886213Gasket Set - Oil Coolergasket
M-4916359Gasket Set - Turbo Installationgasket
MCB3306031MAJOR OVERHAUL GASKET SETgasket
MCB3306032GASKET SETgasket
MCB3306033CYLINDER HEAD GASKET SETgasket
MCB3306121MAJOR OVERHAUL GASKET SETgasket
MCB3306122GASKET SETgasket
MCB3306123CYLINDER HEAD GASKET SETgasket
M-2572752Gasket Set - C18 Front Structuregasket_set
M-3604170Gasket Set - C18 Front Structuregasket_set
M-3605916Gasket Set - C18 Central & Lowergasket_set
M-4154993Gasket Set - Single Cylinder Head - C18gasket_set
M-4446485Gasket Set - C13-C15-C18 Front Structuregasket_set
126-1815Hydraulic - UHEhydraulic_filter
144-6691Hydraulichydraulic_filter
1R0774Filter hydraulichydraulic_filter
328-3655Filter hydraulic/transmissionhydraulic_filter
9T0973Filter hydraulic/transmissionhydraulic_filter
M-2463129Impeller – Water Pumpimpeller
102-2828Filter oiloil_filter
1R-0716Engine Oiloil_filter
1R-1808Engine Oil - ADVoil_filter
1R0716Filter oiloil_filter
1R1808Filter oiloil_filter
2243245Connecting rodother_service
249-0439Oxidation Catalyst Assembly - Roundother_service
256-0331Oxidation Catalyst Assembly - Roundother_service
888-983-7847ENGINE BLOCK CRANKSHAFTother_service
A100Download Specificationother_service
M-3687815Pistonother_service
M-3687816Pistonother_service
M-CK3687815PKit - Cylinder Kitother_service
M-CK3687816PKit - Cylinder Kitother_service
R-20R2284C15/C18/C27/C32 ACERT Trim file (12-digit serial)other_service
R-20R2285C15/C18/C27/C32 ACERT Trim file (12-digit serial)other_service
RSC18ERing Set - Pistonother_service
RSC18E1Ring Set - Pistonother_service
M-3687817Pistonpiston
138-6744Water pump repair kitpump
161-4113Oil pumppump
336-2213Water pumppump
352-0211Water pumppump
384-8611Lift/transfer pumppump
384-8612Lift/transfer pumppump
M-2463130Shaft – Water Pumppump
M-2672839Water pump repair kitpump
M-3848611Pump - Transferpump
142-5867Front sealseal
142-5868Rear sealseal
M-2454630Sensor Assembly - Speedsensor
247-7133Thermostatthermostat
248-5513Thermostatthermostat
420-5855Water Pump Seal Installer (Dimensions: 47 x 45 mm, Weight: .463 kg)water_pump_seal_installer

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Aftermarket parts that fit this engine

60
240A FridayParts $34.29 366-0669 FridayParts $356.99 20R-0956 FridayParts $356.99 171-2212 FridayParts $75.99 265-8713 FridayParts $50.40 3524700 FridayParts $266.20 235-7132 FridayParts $255.60 7G-7889 FridayParts $187.20 SinoCMP $329.00 344-5081 FridayParts $53.50 485-9753 FridayParts $479.63 20R-4050 FridayParts $625.60 591-2386 FridayParts $625.60 398-4747 FridayParts $625.60 344-3456 FridayParts $121.60 344-3455 FridayParts $121.60 201-0950 FridayParts $94.30 252-2237 FridayParts $108.20 153-2521 FridayParts $39.50 219-6488 FridayParts $57.90 335-7371 FridayParts $328.59 518-6322 FridayParts $732.56 335-7370 FridayParts $328.59 353-2833 FridayParts $96.56 3E-6466 FridayParts $73.99 162-2073 FridayParts $73.99 096-1628 FridayParts $48.56 5P-8309 FridayParts $48.90 3E-0156 FridayParts $15.78 SinoCMP $29.00 118-6606 FridayParts $104.45 369-8502 KuduParts $350.00 FridayParts $359.99 247-7133 Amazon eBay $107.00 eBay $41.00 FridayParts $27.50 217-6022 FridayParts $385.56 5P-4924 FridayParts $29.50 171-2211 FridayParts $81.88 SDLM-90-4 FridayParts $81.88 396-6886 FridayParts $506.47 342-8127 FridayParts $285.99 5C-8964 FridayParts $30.99 5C-9029 FridayParts $30.99 327-6125 FridayParts $63.24 327-8515 FridayParts $63.24 122-6585 FridayParts $123.56 148-8385 FridayParts $10.80 150-4037 FridayParts $27.42 261-6847 FridayParts $112.35 3B-6552 FridayParts $7.51 326-7963 FridayParts $48.20 10R-6317 FridayParts $1091.84 440-1616 FridayParts $1091.84 124-5572 KuduParts $50.00 FridayParts $52.10 189-0202 eBay $60.00 FridayParts $79.99 166-1681 FridayParts $79.99 245-3818 FridayParts $230.99 268-6705 KuduParts $49.00 FridayParts $51.20 331-8111 FridayParts $39.99 6I-0273 FridayParts $62.90 177-7375 FridayParts $75.99 KuduParts $143.00 251-7222 KuduParts $145.00 FridayParts $150.00 CA3731765 FridayParts $148.00 15273424 FridayParts $148.00

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Also used in

12
  • Caterpillar 24M — Grader
  • Caterpillar 385C — Excavator Tracked
  • Caterpillar 385CL — Excavator Tracked
  • Caterpillar 385CMHPU — Power Unit
  • Caterpillar 772 — Dump Truck
  • Caterpillar 772G — Haul Truck
  • Caterpillar 834H — Dozer Wheeled
  • Caterpillar 836H — Compactor
  • Caterpillar 988H — Loader Wheeled
  • Caterpillar D9 — Dozer Tracked
  • New Holland FR9080 — Harvester
  • Wirtgen W 2100 — Milling Equipment

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the oil capacity of the Caterpillar C18?

The Caterpillar C18 engine has an oil capacity of 20.8 liters.

What is the displacement of the Caterpillar C18?

The Caterpillar C18 has a displacement of 18.1 liters with 6 cylinders.

Which generators use the Caterpillar C18 engine?

The Caterpillar C18 powers 5 generator set(s), including Caterpillar C18, Caterpillar C18 Diesel Oilfield Generator Set, Caterpillar C18-20' XQ600, Caterpillar D600 GC, Caterpillar XQ570.