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Home›Engines›Caterpillar C27 ATAAC

Caterpillar C27 ATAAC Engine

The Caterpillar C27 ATAAC is a 27.03 L 12-cylinder ta engine. It powers generator sets from Caterpillar, including the LEHX0009-03 and XQ800.

Also known as: CAT C27 ATAAC

Part of the Caterpillar C27 engine family — 4 variants share parts & fitment.

27.03 L
Displacement
12
Cylinders
On this pageService partsSpecsGenerator setsMaintenanceFilter cross-referenceFAQFluids

Service parts for the C27 ATAAC

The cheapest captured merchant offer per filter — see the full cross-reference below for every OEM/aftermarket option.

Oil system

1 required
2P4005Oil filter$23.97PartsGeek

Prices captured from merchant listings; some links are affiliate links. Verify against your serial number before ordering.

Engine specifications

Displacement27.03 L
Cylinders12
AspirationTA

Generator sets powered by this engine

2
Caterpillar LEHX0009-03Caterpillar XQ800

How to read your Caterpillar engine serial & model number →

Maintenance schedule

ItemSpecCapacityPart #Interval
Oil filterDuplex primary with integral water separator and change-over valve, engine mounted secondary filter2P4005 Amazon eBay $32.99 PartsGeek $23.97 KuduParts $39.00
Battery24 VDC/20A battery charger with float/equalize modes and charging ammeter, Two oversized maintenance free batteries, Solar power battery maintainer—
OilLubricating oil system including pump, integral oil cooler, lube oil, filter, filtered crankcase breather system and oil drain line with internal valve routed to connection point accessible from exterior99.0 L—500 hr

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

Recommended fluids

FluidGradeStandardAmbientCapacityNotes
Fuelultra low sulfur diesel (ULSD)Required for Tier 4 Interim emissions compliance

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 C27 family

37
Part #DescriptionCategory
101564109Air Shutoffair_filter
01908191Overspeedother_service
101147116Engine Operation with Active Diagnostic Codesother_service
101154196Engine Operation with Intermittent Diagnostic Codesother_service
101233590Before Starting Engineother_service
101446865Diagnostic Lampother_service
101646248After Starting Engineother_service
102308903Starting with Jump Start Cablesother_service
102327037Starting the Engine (EMCP II and EMCP II+ (If Equipped))other_service
102512380Fault Loggingother_service
301108737Cold Weather Startingother_service
5N-4478Coupling plate assemblyother_service
5N-4479Shim 0.8 mm for coupling plateother_service
5N-4685Varnished cambric tape 15000Vother_service
5N-4686Vinyl plastic electrical tapeother_service
9S-3263Compound for the shoulder of a new zinc rodother_service
CR1-CR6Diodes in bridge rectifier circuitother_service
g00634036Illustration 37: The Location of the GSC+ on the EMCP II+P Control Panelother_service
g00639524Illustration 35: Electronic Modular Control Panel II+ With Paralleling (EMCP II+P)other_service
g00692931Illustration 36: The Synchronization Mode Switchother_service
i01108098Cold Start Strategyother_service
i01359666Crushing Prevention and Cutting Preventionother_service
i01372247Mounting and Dismountingother_service
i01462046Engine Stoppingother_service
i01480768Burn Preventionother_service
i01496776Fire Prevention and Explosion Preventionother_service
i01553111Generator Lead Connectionsother_service
i01593543Generator Isolating for Maintenanceother_service
i01658146Important Safety Informationother_service
i01805780Before Starting Engineother_service
i01830750Engine Maintenance Informationother_service
i01909882Engine Speed Governingother_service
i02106213Electrical Systemother_service
i02136012Engine Startingother_service
i02363871Electronic Modular Control Panel II+ with Paralleling (EMCP II+P)other_service
i02879636Safety Messagesother_service
i07966018Important Safety Informationother_service

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

Filters for this engine

  • Oil filter: Caterpillar 2P4005 Donaldson P554005 Wix 51792 Ac Delco PF879L

Cross-referenced via Donaldson + OEM/engine-maker interchange — options to verify against your serial number, not confirmed for every exact variant.

Also used in

4
  • Caterpillar 24 — Grader
  • Caterpillar MD6250 — Drilling Equipment
  • Caterpillar MD6290 — Drilling Equipment
  • Wirtgen W 2200 — 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 displacement of the Caterpillar C27 ATAAC?

The Caterpillar C27 ATAAC has a displacement of 27.03 liters with 12 cylinders.

Which generators use the Caterpillar C27 ATAAC engine?

The Caterpillar C27 ATAAC powers 2 generator set(s), including Caterpillar LEHX0009-03, Caterpillar XQ800.

What oil filter does the Caterpillar C27 ATAAC use?

The Caterpillar C27 ATAAC uses oil filter part numbers Caterpillar 2P4005, Donaldson P554005, Wix 51792.

How often should you change the oil in the Caterpillar C27 ATAAC?

The Caterpillar C27 ATAAC oil change interval is every 500 hours.