Kenworth Truck Filters Guide

Kenworth at a Glance

Kenworth Truck Company was founded in 1923 in Seattle, Washington, and has been part of PACCAR since 1945. It is one of the best-known Class 8 truck brands in North America, with strong positions in long-haul, vocational, and owner-operator trucking, and a loyal following for its classic long-hood W900. Because Kenworth trucks are common on North American highways and are often run for very high mileage, they generate steady demand for replacement filters.

Kenworth Engines and Why They Matter for Filters

Filter numbers depend on the engine more than on the cab. The same Kenworth T680 can be built with a PACCAR MX-13 or a Cummins X15, and these use different oil, fuel, and crankcase filters. Identify the engine first.

Common Kenworth Filter OE Numbers

While exact filter part numbers depend on the specific engine series and build, the following numbers appear frequently in Kenworth maintenance. PACCAR numbers begin with K37 or P, and Cummins numbers are shown with their Fleetguard cross-references.

Oil Filters

• WIX 57370 – A widely used oil filter for the PACCAR MX-13 in the Kenworth T660, T680, T700, T800 and W900, cross-referenced to Baldwin P40019 and P7354 and Donaldson P550812
• Fleetguard LF14000NN (Cummins 4367100) – The standard spin-on lube filter for the Cummins X15 and ISX15, with LF14001NN as the companion number
• Fleetguard LF9009 (Cummins 3401544) – Lube filter for the Cummins L9 and ISL9 in medium-heavy applications
• Fleetguard LF3970 – Lube filter for the Cummins B6.7 and ISB

Fuel Filters and Water Separators

• K37-1009 – Fuel/water separator element for PACCAR MX-13 engines, cross-referenced to WIX WF10250, Hastings FF1287, and Luber-finer L5109F
• K37-1021 (Fleetguard FS20207) – 10-micron fuel filter for the MX-13 and the Cummins ISX15 and ISX12 in the T660, T680, T700, T800 and W900
• K37-1029, K37-1012 and K37-1011 (Fleetguard FS20172, Donaldson P581298) – Fuel filters for the T660, T680, T700, T880 and W900
• Fleetguard FF5825NN (Cummins 5365988) – Stage 2 fuel filter for the Cummins X15; FF5971N (Cummins 5575143) is the 2020-and-later replacement
• Fleetguard FS19764 (Cummins 102527) – Stage 1 fuel/water separator for the Cummins X15
• Fleetguard FS36401 (PACCAR K37-1004, WIX WF10249) – Fuel/water separator for older Cummins ISX engines, with FF5776 (Cummins 2864993) as the fuel filter

Air Filters

• P621725 – Primary air filter for the T680 and T880 with the MX-11, MX-13, X15 and ISX15, cross-referenced to Donaldson P637453, Baldwin PA32000, Luber-finer LAF6725A, Fleetguard AF24302, and WIX WA11058
• P621730 (Donaldson P637454) – Secondary or companion air filter for the T680 and T880
• P611698 (Fleetguard AF24305) – Air filter for T400, T440, T460, T470, T660, T680, and T800 with the ISM11, ISL9, PX-9, and MX-13
• Fleetguard AF4195 (PACCAR P614986) – Air filter for the Kenworth W900
• Fleetguard AF4197 (PACCAR X011622) – Air filter for the Kenworth W900 and the Peterbilt 389

Crankcase, Cabin, and Other Filters

• 2299013 (also 2116817PE and 2176887PE) – Crankcase filter kit for the PACCAR MX-13 in the T680 and T880
• X1987001 – Cabin air filter set listed for the T680, T700, T800 and T880
• Fleetguard UF106 (Cummins 4388378) – DEF filter for the Cummins X15
• Fleetguard WF2126 (Cummins 4907485) – Coolant filter for the Cummins X15

These numbers are useful references when identifying the correct replacement. Always confirm the exact filter by engine serial number, VIN, or existing filter part number when possible.

Kenworth Cross-Reference Quick Table

Kenworth Filter Maintenance

Oil filters. Replace the oil filter with every oil change. Intervals depend on the duty cycle, with severe or vocational use and high idle time requiring shorter intervals than low-idle line haul. Always use the correct oil specification for the engine and emission level.

Fuel filters. Most modern Kenworth engines use a two-stage fuel system with a fuel/water separator and a main fuel filter. Replace both together, drain the separator, and prime the system after replacement. Low-quality filters can cause low-pressure fuel faults or damage to high-pressure injection components.

Air filters. Check the restriction gauge and replace the primary element when required. Trucks working in construction, gravel, or farm environments need much shorter intervals than highway tractors.

Crankcase and DEF filters. MX-13 engines have a crankcase ventilation filter, and trucks with SCR systems have a DEF filter. Both need replacement on schedule and are easy to forget.

Cabin filters. Replace cabin air filters at least once a year to keep the HVAC system efficient and the cab clean.

Service intervals depend on the engine model, emission standard, oil specification, duty cycle, idle time, and the manufacturer's maintenance schedule. Always follow the schedule for your specific truck.

How to Identify the Correct Kenworth Filter

• Confirm the engine make and model (MX-13, MX-11, PX-9, X15, ISX15 and so on) from the engine data plate or the VIN.
• Note the model year and emission level (EPA10, EPA13, EPA17, EPA21), since filters change between them.
• Record the model (T680, T880, T800, W900), particularly for air filters and cabin filters.
• Compare the old filter's number, height, diameter, and thread against the replacement.

Frequently Asked Questions

What oil filter does a Kenworth T680 with an MX-13 use? Catalogs commonly list WIX 57370 (Baldwin P40019 and P7354, Donaldson P550812) for the MX-13. Verify by engine serial number and emission level.

What air filter does a Kenworth T680 use? P621725 (Donaldson P637453) is commonly listed for the T680 and T880 with MX-11, MX-13, X15, and ISX15 engines. The W900 uses different numbers such as Fleetguard AF4195 or AF4197.

Do Kenworth and Peterbilt trucks use the same filters? Often, yes. Both brands use the same PACCAR MX and Cummins engines, so many oil, fuel, and air filters are identical. Cabin filters and some air filters differ by model.

Can aftermarket filters be used on Kenworth trucks? Yes, if they meet or exceed the original specification for efficiency, flow, and pressure rating and come from a manufacturer able to supply test data. Check warranty terms on newer trucks.

For fleets, owner-operators, and distributors sourcing replacement filters for Kenworth trucks, ADAOER Filter manufactures fuel, oil, air, cabin, and hydraulic filters for trucks, buses, and heavy machinery, and supports OEM/ODM development for custom specifications. Cross-reference lists are available on request.

Brand names and part numbers are used for identification and compatibility reference only. Kenworth, Peterbilt, Mack, PACCAR, Volvo, Cummins, Fleetguard, Donaldson, Baldwin, WIX, Luber-finer, Hastings, and Mann-Hummel are trademarks of their respective owners. Part numbers vary by engine, emission standard, and production date, so always verify the correct filter against the engine model, the truck's VIN, and the existing filter before ordering.