The Caterpillar CAT C18 ATAAC is a 18.13 L 6-cylinder air-to-air aftercooled engine rated at 1500 rpm. It powers generator sets from Caterpillar, including the DM9819 and DM9828. It holds 38 L (10.0 gal) of oil and 20.8 L (5.5 gal) of coolant.
Also known as: Caterpillar CAT C18 ATAAC
Part of the Caterpillar C18 engine family — 8 variants share parts & fitment.
| Oil capacity | 38.0 L |
|---|---|
| Coolant capacity | 20.8 L |
| Displacement | 18.13 L |
| Cylinders | 6 |
| Aspiration | Air-to-Air Aftercooled |
| Rated speed | 1500 rpm |
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | SCAC cooling / jacket water | Generator temperature rise based on a 40 degree C ambient per NEMA MG1-32. | |||
| Engine oil | Lubricating oil | 675.0 L | Sump refill with filter; integral lube oil cooler, gear type lube oil pump | ||
| 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 | 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. |
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 | Axial seal FWS | 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 | Service part / kit |
| 249-0439 | Oxidation Catalyst Assembly - Round | Service part / kit |
| 256-0331 | Oxidation Catalyst Assembly - Round | Service part / kit |
| 385C | Hydraulic Excavator | Service part / kit |
| 888-983-7847 | ENGINE BLOCK CRANKSHAFT | Service part / kit |
| A100 | Download Specification | Service part / kit |
| AEXQ1051-00 | Not explicitly stated in the document. | Service part / kit |
| M-3687815 | Piston | Service part / kit |
| M-3687816 | Piston | Service part / kit |
| M-CK3687815P | Kit - Cylinder Kit | Service part / kit |
| M-CK3687816P | Kit - Cylinder Kit | Service part / kit |
| PEDJ0512-01 | Ripper – Single-Shank | Service part / kit |
| R-20R2284 | C15/C18/C27/C32 ACERT Trim file (12-digit serial) | Service part / kit |
| R-20R2285 | C15/C18/C27/C32 ACERT Trim file (12-digit serial) | Service part / kit |
| RSC18E | Ring Set - Piston | Service part / kit |
| RSC18E1 | Ring Set - Piston | Service part / kit |
| 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 |
| PA140VS | Winch Model PA140VS | Winch |
Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.
The Caterpillar CAT C18 ATAAC engine has an oil capacity of 38.0 liters.
The Caterpillar CAT C18 ATAAC has a displacement of 18.13 liters with 6 cylinders.
The Caterpillar CAT C18 ATAAC powers 2 generator set(s), including Caterpillar DM9819, Caterpillar DM9828.