What is the PACCAR PX-9?
PACCAR lists PX-9 in its medium-duty engine range, separately from PX-7 and the heavy-duty MX engines. The manufacturer’s catalogue publishes a range of ratings, so the PX-9 label should not be treated as one fixed horsepower or torque specification.
What matters in a comparison
For a PX-9 truck, compare the engine’s exact rating with body loads and the intended working day. PTO-driven equipment and repeated low-speed work should be described to the supplier. Ask for the correct service documentation and historical engine hours. When evaluating cost per distance, include body maintenance and other costs that may continue even when monthly kilometres are low.
Fluids & filters
PX engine fluids from the 2026-emissions operator manual (revision 12/2025). Filter numbers below are conditional catalogue matches, not parts assigned to that manual year.
Reference checked:
Identify the unit first
Use these details to match the manufacturer's application record before choosing a fluid or ordering a filter.
- Truck VIN
- Engine model and serial number
- Engine emissions/model year
- Installed filter-housing model and original part number
- Factory coolant label and subsequent coolant-change records
Fluid specifications
Engine oil
SAE 10W-30 meeting API CK-4 or CJ-4 for normal operation above −15°C. API FA-4 is not approved.
2026-emissions PX-9 manual. The manual treats severe service and very cold weather separately; follow its viscosity chart rather than extrapolating this normal-service grade.
Source 1 ↗Engine coolant — nitrited ELC fill
NOAT extended-life coolant meeting ASTM D6210 and Cummins CES 14603; standard factory fill is 50/50 unless otherwise optioned.
2026-emissions PX-9 manual. Verify the installed formulation and follow its separate provisions if optioned with nitrite-free OAT.
Source 1 ↗Filter numbers & cross-references
A catalogue cross-reference links part numbers. It does not confirm that either part fits every version of this model. Match the original part to the unit first, then check the replacement manufacturer's application and any supersession.
Engine oil filter — exact-number cross-reference
First identify this exact original part through the OEM lookup for your engine serial number and VIN. Older catalogue cross-reference only; this does not assign the part to the 2026-emissions engine. The catalogue cross-reference alone does not confirm fitment on every engine in this family.
Application not established by this cross-reference. Confirm this original part number in the manufacturer’s parts catalogue for the exact model and serial number before considering an alternate.
Source 1 ↗Manufacturer catalogue cross-references
- Donaldson P553000Check catalogue ↗
Fuel filter — exact-number cross-reference
First identify this exact original part through the OEM lookup for your engine serial number and VIN. Older catalogue cross-reference only; verify serial-specific filter housing and any later supersession. The catalogue cross-reference alone does not confirm fitment on every engine in this family.
Application not established by this cross-reference. Confirm this original part number in the manufacturer’s parts catalogue for the exact model and serial number before considering an alternate.
Source 1 ↗Manufacturer catalogue cross-references
- Donaldson P553009Check catalogue ↗
PACCAR Parts — Online Parts Counter through your dealer ↗
PACCAR engine manuals by model and emissions year ↗
What still needs unit-specific confirmation
- Confirm current part supersessions and vehicle-specific fitment through the OEM before ordering. Quantities, capacities and maintenance intervals require the serial-specific manual.
Official service and parts references
Source 1 ↗ Source 2 ↗ Source 3 ↗ Source 4 ↗Follow the current manufacturer's manual for the identified unit. This page does not set a drain interval, fill quantity or repair procedure.
Questions to take to the supplier
- Which PX-9 rating is on the build sheet?
- What auxiliary equipment does it operate?
- Are hour-based service records available?
Sources & limits
Manufacturer material supports the identification and overview above. Comparison considerations and supplier questions are Truck University’s original editorial interpretation, prepared with AI assistance. They are not an independent performance test or expert inspection.
Model-family reference only. Availability, specifications and service requirements can differ by year, market and configuration. Verify the actual vehicle or component using its identification and current manufacturer documentation. Do not use this page as a parts-fitment, modification, repair or loading instruction.
Published specifications and examples retain their labelled units; the header preferences apply to calculators.
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