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Caterpillar C18 Engine

Name: Caterpillar C18 Engine
Brand: Caterpillar

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 XQ1140. It holds 20.8 L (5.5 gal) of oil and 77 L (20.3 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

Cylinders

1800 rpm

Rated speed

545 kW

Gross power

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids

Engine specifications

Oil capacity	20.8 L
Coolant capacity	77.0 L
Displacement	18.1 L
Cylinders	6
Aspiration	ATAAC
Rated speed	1800 rpm
Gross power	545 kW

Generator sets powered by this engine

Caterpillar C18 Caterpillar C18 Diesel Oilfield Generator SetCaterpillar C18-20' XQ600Caterpillar XQ1140

How to read your Caterpillar engine serial & model number →

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Dual element air cleaner		—	200 hr
Fuel filter	Primary fuel filter with integral water separator, Secondary fuel filters		—	200 hr
Oil filter	Lubricating oil and filter		—	200 hr
Battery	Batteries with rack and cables		—	200 hr
Belt	Fan and belt guards, Belt		—	200 hr
Coolant	Caterpillar Extended Life Coolant	20.8 l	—
Coolant filter			—
Oil	Lubricating oil and filter	20.8 l	—
Spark plug	Spark Plug		—

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

Service intervals

Item	Action	Hours	Notes
Primary air filter element	Change	250 hr	When changing the primary element at 250 operating hours (basis of the without-indicator filter-change comparison)
oil	Change	500 hr	3000 Series service intervals increased to 500 hours as standard (3013C, 3024C, 3054, 3056)
Secondary air filter element	Change	750 hr	When changing the secondary element at 750 operating hours (basis of the without-indicator filter-change comparison)
minor overhaul	Other	20000 hr	3600 engines designed to run 20 000 hours between minor overhauls using No. 2 fuel
major overhaul	Other	40000 hr	3600 engines designed to run 40 000 hours between major overhauls using No. 2 fuel
cylinder liners and pistons	Other	80000 hr	3600 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

Type	Item	Value	Unit	Condition
Other	Radiator cooling package design ambient temperature	48.9	°C (120° F)	with 50/50 water/Extended Life Coolant mixture
Other	Radiator cooling package maximum elevation	1524	m (5000 ft)	with 50/50 water/Extended Life Coolant mixture
Pressure	Unit injector fuel injection pressure	1240	bar (18 000 psi)
Torque	Air compressor SAE "A" hydraulic pump drive maximum torque (374 L/min and 467 L/min compressors)	60	N•m (44 lb-ft)	C7, C9 ACERT

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

Fluid	Grade	Standard	Ambient	Notes
Coolant	50/50 mixture water/Caterpillar Extended Life Coolant		below 48°C	Radiator 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)
Coolant	Cat DEAC			Diesel; 3,000 Service Hours or Three Years; annual S·O·SSM Level 2 coolant sampling and analysis
Coolant	Cat ELC			Diesel; 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
Coolant	Cat NGEC			Natural Gas; 16,000 Service Hours or Three Years; use interval that occurs first
Engine oil	Cat NGEO			Natural Gas
Engine oil	Cat Arctic DEO SYN SAE 0W-30		-40°C to 30°C	Engine Crankcase; Industrial Engines
Engine oil	Cat DEO SYN SAE 5W-40		-30°C to 50°C	Engine Crankcase; Industrial Engines
Engine oil	Cat DEO SAE 10W-30		-18°C to 40°C	Engine Crankcase; Industrial Engines
Engine oil	Cat DEO SAE 15W-40		-9°C to 50°C	Engine Crankcase; Industrial Engines
Fuel		LCV = 42700 kJ/kg		MaK technical data; without engine-driven pumps, tolerance 5%
Fuel	35° 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)
Fuel	No. 2 fuel			3600 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
Grease	Cat Generator Set Grease			Part 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.

Parts cataloged across the Caterpillar C18 family

140

Part #	Description	Category
106-3973	Air filter inner	air_filter
151-7737	Air Primary	air_filter
189-0202	Air Secondary	air_filter
1W-3636	Air Secondary	air_filter
1W-3637	Air Primary	air_filter
246-5009	Air	air_filter
246-5010	Air	air_filter
4N0015	Air filter outer	air_filter
7C-1571	Air Primary	air_filter
8N6309	Air filter outer	air_filter
9Y-3879	Air	air_filter
6T1395	Alternator	alternator
118-2018	V-belt	belt
4N6302	V-belt	belt
M-CK3687817P	Cylinder Kit	cylinder_kit
133-5673	Fuel/Water Separator	fuel_filter
1R-0749	Fuel Secondary - ADV	fuel_filter
1R-0762	Fuel Secondary - ADV	fuel_filter
1R-0770	Fuel/Water Separator	fuel_filter
1R-0781	Fuel/Water Separator - ADV	fuel_filter
1R0749	Filter fuel	fuel_filter
1R0755	Filter fuel	fuel_filter
326-1641	Filter water separator	fuel_filter
326-1642	Filter water separator	fuel_filter
326-1643	Filter water separator	fuel_filter
3S3875	Filter fuel	fuel_filter
9N3717	Filter water separator	fuel_filter
4N1151	Gasket oil pan	gasket
M-4220925	Gasket Set - Rear Structure	gasket
M-4337629	Gasket Set - Rear Structure	gasket
M-4351087	Gasket Set - Rear Structure	gasket
M-4361559	Gasket Set - Front Structure	gasket
M-4365757	Gasket Set - Turbo Installation	gasket
M-4452666	Gasket Set - Rear Structure	gasket
M-4496052	Gasket Set - Oil Cooler & Lines	gasket
M-4588198	Gasket Set - Front Structure	gasket
M-4682161	Gasket Set - Cylinder Head	gasket
M-4685553	Gasket Set - Central & Lower	gasket
M-4685746	Gasket Set - Cylinder Head	gasket
M-4687363	Gasket Set - Water Pump	gasket
M-4687942	Gasket Set - Turbo Installation	gasket
M-4690626	Gasket Set - Central & Lower	gasket
M-4690822	Gasket Set - Turbo Installation	gasket
M-4690823	Gasket Set - Cylinder Head	gasket
M-4690878	Gasket Set - Cylinder Head	gasket
M-4692381	Gasket Set - Central & Lower	gasket
M-4692382	Gasket Set - Fuel System	gasket
M-4692388	Gasket Set - Cylinder Head	gasket
M-4701892	Gasket Set - Turbo Installation	gasket
M-4733264	Gasket Set - Rear Structure	gasket
M-4886213	Gasket Set - Oil Cooler	gasket
M-4916359	Gasket Set - Turbo Installation	gasket
MCB3306031	MAJOR OVERHAUL GASKET SET	gasket
MCB3306032	GASKET SET	gasket
MCB3306033	CYLINDER HEAD GASKET SET	gasket
MCB3306121	MAJOR OVERHAUL GASKET SET	gasket
MCB3306122	GASKET SET	gasket
MCB3306123	CYLINDER HEAD GASKET SET	gasket
M-2572752	Gasket Set - C18 Front Structure	gasket_set
M-3604170	Gasket Set - C18 Front Structure	gasket_set
M-3605916	Gasket Set - C18 Central & Lower	gasket_set
M-4154993	Gasket Set - Single Cylinder Head - C18	gasket_set
M-4446485	Gasket Set - C13-C15-C18 Front Structure	gasket_set
126-1815	Hydraulic - UHE	hydraulic_filter
144-6691	Hydraulic	hydraulic_filter
1R0774	Filter hydraulic	hydraulic_filter
328-3655	Filter hydraulic/transmission	hydraulic_filter
9T0973	Filter hydraulic/transmission	hydraulic_filter
M-2463129	Impeller – Water Pump	impeller
102-2828	Filter oil	oil_filter
1R-0716	Engine Oil	oil_filter
1R-1808	Engine Oil - ADV	oil_filter
1R0716	Filter oil	oil_filter
1R1808	Filter oil	oil_filter
2243245	Connecting rod	other_service
249-0439	Oxidation Catalyst Assembly - Round	other_service
256-0331	Oxidation Catalyst Assembly - Round	other_service
888-983-7847	ENGINE BLOCK CRANKSHAFT	other_service
A100	Download Specification	other_service
M-3687815	Piston	other_service
M-3687816	Piston	other_service
M-CK3687815P	Kit - Cylinder Kit	other_service
M-CK3687816P	Kit - Cylinder Kit	other_service
R-20R2284	C15/C18/C27/C32 ACERT Trim file (12-digit serial)	other_service
R-20R2285	C15/C18/C27/C32 ACERT Trim file (12-digit serial)	other_service
RSC18E	Ring Set - Piston	other_service
RSC18E1	Ring Set - Piston	other_service
g00284658	Illustration 17 EPA Emissions Certiﬁcation Film	other_service
g00415538	Illustration 18 European Emissions Certiﬁcation Film	other_service
g00702020	Wear a hard hat, protective glasses, and other protective equipment, as required.	other_service
g00704000	Illustration 8	other_service
g00704059	Illustration 9	other_service
g00771448	Grounding Practices	other_service
g01054560	Illustration 23 Typical performance monitor panel	other_service
g01054562	Illustration 24 Typical performance monitor panel for totals	other_service
g01054565	Illustration 25 Typical performance monitor panel for settings	other_service
g01054566	Illustration 26 Typical performance monitor panel for service	other_service
g01065152	Illustration 16 (1) Serial number plate (2) Information plate	other_service
g01233007	Illustration 20	other_service
g01416712	Illustration 1	other_service
g01459611	Illustration 21	other_service
g01459691	Illustration 22 Caterpillar Messenger Display	other_service
i00844066	Emissions Certiﬁcation Film	other_service
i00863835	Self-Diagnostics	other_service
i00911989	Before Starting Engine	other_service
i01103904	Engine Starting	other_service
i01359666	Crushing Prevention and Cutting Prevention	other_service
i01372247	Mounting and Dismounting	other_service
i01372254	Fire Prevention and Explosion Prevention	other_service
i01463253	Diagnostic Lamp	other_service
i01646248	SMCS Code: 1000	other_service
i01658146	Important Safety Information	other_service
i01934760	SMCS Code: 1000; 1401; 1402; 1900	other_service
i01988813	Product Lifting	other_service
i02068367	Product Storage	other_service
i02088692	Plate Locations and Film Locations	other_service
i02109067	Operation and Maintenance Manual, 'Maintenance Interval Schedule'	other_service
i02164876	Reference Numbers	other_service
i02469632	Electrical System	other_service
i02496338	Diagnostic Flash Code Retrieval	other_service
i02566298	General Hazard Information	other_service
i02784356	Engine Electronics	other_service
i02840188	Safety Messages	other_service
i02944987	Monitoring System	other_service
M-3687817	Piston	piston
138-6744	Water pump repair kit	pump
161-4113	Oil pump	pump
336-2213	Water pump	pump
352-0211	Water pump	pump
384-8611	Lift/transfer pump	pump
384-8612	Lift/transfer pump	pump
M-2463130	Shaft – Water Pump	pump
M-2672839	Water pump repair kit	pump
M-3848611	Pump - Transfer	pump
142-5867	Front seal	seal
142-5868	Rear seal	seal
M-2454630	Sensor Assembly - Speed	sensor
247-7133	Thermostat	thermostat
248-5513	Thermostat	thermostat
420-5855	Water 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

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 $187.20 344-5081 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 $15.78 118-6606 FridayParts $104.45 369-8502 KuduParts $350.00 247-7133 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 $50.00 189-0202 eBay $60.00 FridayParts $79.99 166-1681 FridayParts $79.99 245-3818 FridayParts $230.99 268-6705 KuduParts $49.00 331-8111 FridayParts $39.99 6I-0273 FridayParts $62.90 177-7375 FridayParts $75.99 251-7222 KuduParts $145.00 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

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 4 generator set(s), including Caterpillar C18, Caterpillar C18 Diesel Oilfield Generator Set, Caterpillar C18-20' XQ600, Caterpillar XQ1140.