PACCAR Engines | Oil Specs & Service Guides
PACCAR engine oil specifications vary by engine year, viscosity grade and operating conditions. Find API CK-4 requirements and service guidance for MX-series engines powering Kenworth and Peterbilt trucks.
Last reviewed: August 2026 | Current PACCAR MX oil chart checked
Start with the engine badge and model year. Current EPA 2017, 2021 and 2024 PACCAR MX-11 and MX-13 guidance specifies API CK-4 across several viscosity grades. Use the grade allowed for your ambient temperature and confirm the schedule in the operator's manual for your engine year and duty cycle.
Choose Your PACCAR Engine | MX-13 or MX-11
Both use PACCAR's MX oil guidance, but capacity, application and maintenance details are engine-specific. Open the matching guide before ordering oil or setting a drain interval.
PACCAR MX-13
The larger MX platform used in heavy-duty Kenworth and Peterbilt applications.
- Current oil category: API CK-4
- Viscosity: multiple PACCAR-listed grades
- Service interval: model year and duty cycle matter
PACCAR MX-11
The lighter MX platform for weight-sensitive regional, vocational and over-the-road applications.
- Current oil category: API CK-4
- Viscosity: multiple PACCAR-listed grades
- Service interval: model year and duty cycle matter
Match the Oil | Not Just the Engine Name
API Category | Start Here
PACCAR's current EPA 2017, EPA 2021 and EPA 2024 MX chart specifies API CK-4 for the listed viscosity grades. It does not list API FA-4.
Viscosity | Check Temperature
Do not assume every MX engine is locked to 15W-40. PACCAR's current chart lists 5W-40, 10W-40, 15W-40, 5W-30 and 10W-30 options, with category and model-year notes.
Drain Interval | Check Duty Cycle
Idle time and severe or vocational use change the maintenance schedule. Use the engine-specific operator's manual instead of copying another truck's interval.
Technical basis: PACCAR MX Engine Oil Specifications and Service Intervals for EPA 2017, 2021 and 2024 engines. Older engines can have different oil and service requirements; confirm by engine year and manual.
PACCAR Engine Oil | Quick Answers
What oil category do current PACCAR MX engines use?
PACCAR's published chart for EPA 2017, EPA 2021 and EPA 2024 MX-11 and MX-13 engines specifies API CK-4 for its listed viscosity grades.
Do all PACCAR MX engines require 15W-40?
No. PACCAR's current MX chart lists several viscosity grades. Pick the grade allowed for the engine year and operating temperature, then verify it against the operator's manual.
Can I use API FA-4 in a PACCAR MX-11 or MX-13?
Do not substitute FA-4 based on viscosity alone. PACCAR's current published MX chart calls for CK-4 and does not list FA-4. Follow the manual for the exact engine year.
How often should PACCAR MX engine oil be changed?
The interval depends on model year, duty cycle and idle time. Use the schedule for your specific engine; severe and vocational service generally requires shorter intervals than normal line haul.