The Caterpillar C18 ATAAC is a 18.13 L 6-cylinder air-to-air aftercooled engine rated at 1500 rpm, producing up to 600 kW. It powers generator sets from Caterpillar, including the C18, DM8518, DM8522 and DM9628. It holds 38 L (10.0 gal) of oil and 645 L (170.4 gal) of coolant.
Also known as: CAT C18 ATAAC
Part of the Caterpillar C18 engine family — 3 variants share parts & fitment.
The cheapest captured merchant offer per filter — see the full cross-reference below for every OEM/aftermarket option.
Prices captured from merchant listings; some links are affiliate links. Verify against your serial number before ordering.
| Oil capacity | 38.0 L |
|---|---|
| Coolant capacity | 645.0 L |
| Displacement | 18.13 L |
| Cylinders | 6 |
| Aspiration | Air-to-Air Aftercooled |
| Rated speed | 1500 rpm |
| Gross power | 600 kW |
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 1250 hr | |||
| Fuel filter | 33674 | 1250 hr | Amazon eBay $50.97 PartsGeek $19.97 KuduParts $147.00 | ||
| Oil filter | 2P4005 | 1250 hr | Amazon eBay $32.99 PartsGeek $23.97 KuduParts $39.00 | ||
| Battery | — | 1250 hr | |||
| Belt | — | 1250 hr | |||
| Coolant | — | 1250 hr | |||
| Oil | Sump refill with filter | 64.0 L | — | ||
| Spark plug | — | 1250 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | 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.
| 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.
| Fluid | Grade | Standard | Ambient | Capacity | 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 | |||
| Coolant | SCAC cooling / jacket water | Generator temperature rise based on a 40 degree C ambient per NEMA MG1-32. | |||
| Engine oil | Cat NGEO | Natural Gas | |||
| Engine oil | Lubricating oil | 675.0 L | Sump refill with filter; integral lube oil cooler, gear type lube oil pump | ||
| 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 | LHV of 42 780 kJ/kg (18,390 Btu/lb) at 29 C (85 F), weighing 838.9 g/liter (7.001 lbs/U.S. gal.) | |||
| 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 diesel fuel, 35º API gravity | LHV 42 780 kJ/kg (18,390 Btu/lb) | Weighing 838.9 g/liter (7.001 lbs/U.S. gal.), used at 29º C (85º F). Consult Cat dealer for Low Sulfur fuel and Biodiesel capability. | ||
| 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.
| 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.
Cross-referenced via Donaldson + OEM/engine-maker interchange — options to verify against your serial number, not confirmed for every exact variant.
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.
The Caterpillar C18 ATAAC engine has an oil capacity of 38.0 liters.
The Caterpillar C18 ATAAC has a displacement of 18.13 liters with 6 cylinders.
The Caterpillar C18 ATAAC powers 6 generator set(s), including Caterpillar C18, Caterpillar DM8518, Caterpillar DM8522, Caterpillar DM9628, Caterpillar DM9824.
The Caterpillar C18 ATAAC uses oil filter part numbers Caterpillar 2P4005, Donaldson P554005, Wix 51792.
The Caterpillar C18 ATAAC uses fuel filter part numbers Donaldson P551319, Wix 33674.
The Caterpillar C18 ATAAC uses air filter part numbers Caterpillar 2453818, Caterpillar 2901936, Caterpillar 2453819.