Every CAT engine needs a complete filter service at the correct interval — but locating the right part numbers across multiple filter types for a specific engine series takes longer than it should.
This guide consolidates every filter required for a complete CAT service by engine platform, oil, fuel, air, and coolant, with the OEM part numbers operators and fleet managers actually search for. C7 through C15 ACERT, 3116 through 3406E, and the legacy 3208 platform are all covered.
Use it as a service planning reference, a parts ordering checklist, or a cross-reference against what your current supplier is providing.
For the complete range of CAT-compatible filter and service parts, visit our heavy equipment filters and service parts hub.
Why Filter Specification Matters on CAT Engines
CAT engines are designed with filter bypass pressures, media efficiency ratings, and element dimensions calibrated for specific flow rates and contamination loads. A filter that physically fits but does not meet the bypass pressure specification allows contaminated oil or fuel into the system before the element reaches its rated capacity.
This is the practical difference between OEM-specification filters and unverified alternatives, not the physical dimensions, but the performance specification that determines how much protection the engine actually receives between service intervals.
Confirm part numbers against your engine serial number before ordering. CAT has run specification changes within engine families. The C15 ACERT and non-ACERT platforms use different filter specifications across some categories, and the 3406B and 3406E differ on fuel filtration requirements.
C7 and C9 Engine Filter Requirements
The C7 (7.2 litre) and C9 (8.8 litre) are mid-range CAT engines used across the 320C, 320D, 323D, and 330C excavator series.
Engine oil filter: 1R-0739 is the primary reference for both platforms. Confirm against the engine arrangement number; some C9 configurations run the 1R-0716 element in a dual-filter configuration.
Fuel filter and water separator: 326-1644 primary fuel filter element; 133-5673 water separator element. The water separator on C7 and C9 applications should be serviced at every fuel filter change, not on a separate interval.
Engine air filter: 6I-2501 primary element; 6I-2502 safety element. Always replace the safety element when the primary is replaced on construction site applications where dust loading is high.
For CAT-compatible engine oil filters across the C7 and C9 series, visit our CAT engine oil filters page.
C13 Engine Filter Requirements
The C13 (12.5 litre) powers excavators in the 336 and 340 series and large dozer applications.
Engine oil filter: 1R-0739 primary element shared with the C7/C9 on standard configuration. Dual-filter C13 builds use 1R-1807 elements in a remote-mounted secondary filter housing.
Fuel filter: 360-8960 primary fuel filter; 326-1644 secondary. The C13 uses a two-stage fuel filtration system; both stages require replacement at each fuel service interval.
Air filter: 6I-2501 primary; 6I-2502 safety. Same elements as C7/C9 confirm housing configuration before ordering, as some C13 applications use a larger diameter housing requiring 6I-2500.
For CAT fuel filter and water separator options across C13 applications, visit our CAT fuel filters and water separators page.
C15 and C15 ACERT Filter Requirements
The C15 (15.2 litre) is the highest-volume filter search in the entire CAT engine family. It powers large excavators, mining haul trucks, and dozer applications across a long production run with multiple specification variants.
Engine oil filter — non-ACERT C15: 1R-1807 is the primary reference. This is the most searched CAT oil filter part number globally. Confirm it applies to your specific C15 arrangement number before ordering.
Engine oil filter — C15 ACERT: 1R-0750 primary element on ACERT-equipped builds. The ACERT system changes the oil circuit flow rate requirement;s do not substitute 1R-1807 on an ACERT engine without confirming the arrangement number.
Fuel filter: 326-1644 primary; 133-5673 water separator. The 1R-0808 secondary element is required on C15 builds with a secondary fuel filter housing; confirm against your arrangement number.
Air filter: 6I-2500 primary; 1P-0711 safety element on most C15 configurations.
Coolant filter: 9N-6277 coolant conditioner element required at every coolant service to maintain DCA4 additive concentration in the cooling system. This element is commonly overlooked,d and its omission accelerates linear pitting on C15 applications.
For CAT engine air filter elements across C13 and C15 applications, visit our CAT engine air filters page.
3306, 3406, 3406B, and 3406E Filter Requirements
The 3306 and 3406 families represent the largest legacy CAT engine fleet still in productive service globally.
3306 engine oil filter: 1R-0716 primary element. This is the correct reference for the majority of 3306 builds. Some 3306 applications use a cartridge-style housing requiring the 7W-2327 element.
3406 and 3406B oil filter: 1R-0716 on pre-electronic builds; 1R-0739 on later 3406B configurations. Confirm from the engine serial number prefix that the 7FB and 8TC prefix 3406B builds use different specifications within the same model designation.
3406E oil filter: 1R-0739 primary. The 3406E introduced electronic unit injection and changed the oil circuit flow demand. Do not substitute 3406B filter specifications on a 3406E without confirming the arrangement number.
Fuel filtration — 3406 family: 1R-0749 primary fuel filter element across most 3406 configurations. The 3406E uses 326-1644 on later builds; confirm from the injection system type before ordering.
3208 legacy platform: 1R-0716 engine oil filter; 1R-0749 fuel filter on most 3208 builds. OEM availability is limited on some 3208 filter references. Quality aftermarket elements to OEM specification are the practical sourcing route for this platform.
For CAT coolant filter elements and DCA4 service parts, visit our CAT coolant filters and cooling system service parts page.
Using Part Numbers to Verify Aftermarket Quality
The OEM part numbers listed in this guide serve a second purpose beyond ordering; they are the specification reference against which any aftermarket alternative should be verified.
A quality aftermarket CAT filter lists the OEM part number it replaces, the bypass pressure specification it meets, and the filtration efficiency rating. A supplier who cannot provide this information for the aftermarket filters they stock is not a supplier whose products can be verified against OEM specifications.
The bypass pressure and efficiency rating are the two values that determine whether a filter provides the protection the engine was designed to receive, not the dimensions, and not the price.
Conclusion
A complete CAT filter service is straightforward when the part numbers are confirmed against the correct engine arrangement number. The 1R-1807 and 1R-0750 distinction on C15 ACERT versus non-ACERT. The 3406B versus 3406E fuel filter specification. The coolant conditioner element that most operators omit. These details are what separate a complete service from one that leaves gaps in engine protection.
At Imara Engineering Supplies, we stock OEM-specification CAT engine oil filters, fuel filters, air filters, and coolant filter elements confirmed against engine serial numbers and arrangement numbers before every order.
Contact our team with your engine serial number and arrangement number, or visit our CAT engine oil filters page to start your filter service order.
