PACCAR
PACCAR MX-11: Specs, Service Intervals, Lifespan & Common Problems
The PACCAR MX-11 is a 10.8-liter inline-six diesel, the smaller of PACCAR's two MX engines. PACCAR's 2024 spec sheet lists 355–445 hp and 1,250–1,700 lb-ft. Dry weight is 2,200 lb and oil system capacity is 39 U.S. quarts. The oil interval is up to 75,000 miles for line haul under 20% idle. The major-components warranty is 5 years or 500,000 miles.
PACCAR published the PACCAR MX-11 figures in its own documents. Last reviewed November 3, 2026.
What are the PACCAR MX-11 specs?
| Configuration | Inline 6-cylinder |
|---|---|
| Displacement | 10.8 L |
| Bore × stroke | 123 mm × 152 mm |
| Power | 355–445 hp |
| Peak torque | 1,250–1,700 lb-ft |
| Dry weight | 2,200 lb |
| Oil system capacity | 39 U.S. qt |
| Governed speed | 2,100 rpm |
| Maximum operating weight | 110,000 lb |
| Certification | EPA 2024 |
| Truck models | Not listed on the spec sheet. Trade press reported the MX-11 in the Peterbilt 579 and the Kenworth T680 when it launched. |
Fitted in the Peterbilt 579 and Kenworth T680; compare with the truck model specs.
How long does a PACCAR MX-11 last?
PACCAR's 2024 MX-11 sheet does not state a B10 design life. It says the engines are built for durability with multi-million-mile endurance testing. That describes the testing, not how long an engine lasts. PACCAR does print a 1-million-mile B10 for the MX-13 on its 2021 sheet. Do not assume the MX-11 carries the same figure. What PACCAR prints for the MX-11 is its warranty.
Warranty, as the OEM lists it
- Base warranty: 2 years / 250,000 miles (400,000 km)
- Major components: 5 years / 500,000 miles (800,000 km)
- Extended protection plans are available
PACCAR MX-11 oil capacity: how much oil does it hold?
39 U.S. quarts. PACCAR lists this as the oil system capacity on its 2024 MX-11 spec sheet.
Capacity is how much oil goes in. The interval is how often you change it. The next section covers the interval.
How often should you change the oil in a PACCAR MX-11?
PACCAR's 2024 MX-11 sheet lists the oil and filter and the fuel filter together. The two use the same mileage at each duty level. The sheet says to use the MX Engine Operator's Manual for the full requirements.
| Duty cycle | Oil and filter interval |
|---|---|
| Normal / line haul, under 20% idle time | 75,000 miles (120,000 km) |
| Normal / line haul, over 20% idle time | 50,000 miles (80,000 km) |
| Severe / vocational duty | 30,000 miles (48,000 km) |
- Coolant filter and DEF filter: 300,000 miles (480,000 km) each.
- Idle time is what moves you between the top two rows. Many drivers underestimate their real idle percentage. So check your ECM data instead of guessing.
Put your PACCAR MX-11 interval on a schedule with the maintenance scheduler.
What should you check before you buy a used truck with a PACCAR MX-11?
- Ask for service records and compare them with the oil interval table above.
- Get the warranty terms in writing for that exact truck, and ask whether they carry over to the next owner.
- Check recall status by VIN. We have not searched recalls for this engine.
What are the common problems with the PACCAR MX-11?
We found no repair report that is specific to the MX-11 that we could rely on. Forum posts and parts-seller pages mix it with the MX-13. They name aftertreatment and DEF faults most often. That is true of every modern SCR diesel. So this page lists no engine-specific issues. Judge a used truck by its service record, not its badge.
How does it compare with other heavy-duty engines?
Each engine guide on this site follows the same format and the same sourcing rule, so you can read thePACCAR MX-11 next to the other engines.
Frequently Asked Questions
How much oil does a PACCAR MX-11 hold?+
39 U.S. quarts. PACCAR lists this as the oil system capacity on its 2024 MX-11 spec sheet. That tells you how much oil to buy. The service interval tells you when to change it, so read both.
Is the PACCAR MX-11 a good engine?+
PACCAR backs it with a 5-year/500,000-mile major-components warranty and a 75,000-mile oil interval for line haul under 20% idle. It is lighter than a 13-liter engine by PACCAR's own count. But the sheet states no B10 design life, and we found no engine-specific repair data. So judge a specific truck by its service history.
What is the difference between the MX-11 and the MX-13?+
Size and rating. The MX-11 is 10.8 liters and 355–445 hp. The MX-13 is 12.9 liters and 405–510 hp. PACCAR lists 2,200 lb dry for the MX-11 and 2,500 lb for the MX-13. The oil intervals and warranty terms on the sheets are the same. See the full comparison page for the table.
How much horsepower does an MX-11 have?+
PACCAR's 2024 sheet lists 355 to 445 hp and 1,250 to 1,700 lb-ft of torque. The top rating is 445 hp with 1,700 lb-ft at 900 rpm.
How often should I change the oil in an MX-11?+
PACCAR lists 75,000 miles for line haul with under 20% idle time. It lists 50,000 miles over 20% idle, and 30,000 miles for severe or vocational duty. Idle percentage is the deciding factor. So check your actual number.
How much lighter is the MX-11 than a 13-liter engine?+
PACCAR says the MX-11 weighs 300 lb less than a 13-liter engine. Its sheets list 2,200 lb for the MX-11 and 2,500 lb for the MX-13, which matches. Each sheet is the maker's own figure, so treat it as an indication, not a scale test.
Sources
Run a PACCAR MX-11 truck? Let a dispatcher handle the rest.
Grow Trucking finds loads, negotiates rates and does the paperwork for owner-operators and small fleets. Tell us about your PACCAR MX-11 truck and we will show you how we can help.
Also: About Grow Trucking · Refer a carrier · Trucking blog
Specs, intervals and warranty terms for the PACCAR MX-11 change by model year and configuration. Confirm the exact figures for a specific truck against PACCAR's current documents and your written warranty before you make a purchase or maintenance decision. Reported-issue information comes from repair and parts businesses, not from an independent failure study.
Free tools for a PACCAR MX-11 truck
Decode PACCAR MX-11 fault codes, keep its service on schedule and check a truck before you buy.
- Diesel Fault Code Lookup (SPN/FMI)Decode the SPN/FMI fault codes the PACCAR MX-11 reports.
- Preventive Maintenance SchedulerTrack PACCAR MX-11 oil and filter intervals by odometer for your duty cycle.
- Breakdown Cost EstimatorEstimate what a PACCAR MX-11 breakdown costs in repairs and lost revenue.
- Truck Breakdown TriageIf the PACCAR MX-11 shows a red lamp or overheats, see if you should stop now.