PACCAR engines
PACCAR’s truck-engine range includes heavy-duty MX and medium-duty PX families. The letters and suffix identify a starting point, but the engine serial number, emissions generation and truck build determine the applicable rating and service information. Compare engines within a complete chassis specification. A fuel-efficiency claim or a maximum output figure cannot establish a particular truck’s operating cost or its suitability for every application.
Compare the model families
| Model / family | Application | Overview | Model notes |
|---|---|---|---|
| MX-13 | Heavy-duty diesel engine | PACCAR identifies its EPA MX-13 as a 12.9 L engine. The MX-13 designation spans model years, so the current product page should be read alongside the serial-number and year-specific documentation for a used truck. Its heavy-duty role differs from the PX medium-duty family. | Read the profile → |
| MX-11 | Heavy-duty MX-family diesel | MX-11 is a PACCAR heavy-duty engine designation separate from MX-13. PACCAR provides an MX-11 operator’s manual for the 2024 generation. Use the manual and specification appropriate to the individual engine rather than transferring ratings from a different MX model or market. | Read the profile → |
| PX-9 | Medium-duty PX-family engine | 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. | Read the profile → |
| PX-7 | Medium-duty PX-family engine | The PX-7 is PACCAR’s smaller PX-family medium-duty engine offering. Its product page describes electronic engine control and a variable-geometry turbocharger. Confirm the installed generation and rating rather than assuming every PX-7 shares all details of a current specification. | Read the profile → |
Bring the exact specification.
The family name helps organize your search. The build sheet, serial number and relevant manufacturer documentation identify what is installed. Compare like-for-like applications and request evidence for cost or performance claims.
Manufacturer references support the model facts. Our examples and comparisons are editorial interpretation prepared with AI assistance, not road tests or an expert inspection.
Check the year, market and exact build before applying a specification. This guide does not authorize parts fitment, repairs, modifications or loading.
PACCAR manufacturer reference ↗Independent editorial resource. Brand names identify equipment; they do not imply a partnership or endorsement.