Engine comparison
PACCAR MX-11 vs MX-13: Specs, Weight and Oil Capacity Compared
The PACCAR MX-11 is 10.8 liters and the MX-13 is 12.9 liters. PACCAR lists the MX-11 at 355–445 hp and the MX-13 at 405–510 hp. The MX-11 is 300 lb lighter on PACCAR's sheets (2,200 lb against 2,500 lb) and holds 39 qt of oil against 42. The oil intervals and warranty terms on the two sheets are the same. So the choice comes down to the rating you need and the weight you pull. There is no spec-sheet winner.
Figures for MX-11 vs MX-13 are taken from the manufacturers' own published documents. Last reviewed November 3, 2026.
MX-11 vs MX-13: side-by-side specs
| Spec | PACCAR MX-11 | PACCAR MX-13 |
|---|---|---|
| Displacement | 10.8 L | 12.9 L |
| Configuration | Inline 6-cylinder | Inline 6-cylinder |
| Bore × stroke | 123 mm × 152 mm | 130 mm × 162 mm |
| Power | 355–445 hp | 405–510 hp |
| Peak torque | 1,250–1,700 lb-ft | 1,550–1,850 lb-ft |
| Dry weight | 2,200 lb | 2,500 lb |
| Oil system capacity | 39 U.S. qt | 42 U.S. qt |
| Governed speed | 2,100 rpm | 2,200 rpm |
| Oil and filter interval, line haul under 20% idle | 75,000 mi | 75,000 mi |
| Oil and filter interval, line haul over 20% idle | 50,000 mi | 50,000 mi |
| Oil and filter interval, severe or vocational | 30,000 mi | 30,000 mi |
| Coolant filter and DEF filter | 300,000 mi each | 300,000 mi each |
| Base warranty | 2 years / 250,000 mi | 2 years / 250,000 mi |
| Major-components warranty | 5 years / 500,000 mi | 5 years / 500,000 mi |
| Published design life (B10) | Not stated on the 2024 sheet | 1 million miles (1.6 million km), per the 2021 sheet |
Full detail for each engine: PACCAR MX-11 guide and PACCAR MX-13 guide.
What actually decides MX-11 vs MX-13?
We don't name a winner in MX-11 vs MX-13: there's no independent, like-for-like study of fuel economy or reliability for these engines. These are the facts that decide it for a given truck and duty cycle.
- The rating you need sets the engine
- The MX-11 tops out at 445 hp and 1,700 lb-ft. The MX-13 goes up to 510 hp and 1,850 lb-ft. If you need a rating above the MX-11's range, the MX-13 is the only one of the two that offers it. If you do not, the lighter engine is worth a look.
- Weight and payload
- PACCAR says the MX-11 weighs 300 lb less than a 13-liter engine. Its two sheets agree: 2,200 lb against 2,500 lb. Each is PACCAR's own figure, so read it as an indication. Whether 300 lb matters depends on how close you run to the legal weight limit.
- Maximum operating weight
- PACCAR's MX-11 sheet lists a maximum operating weight of 110,000 lb. We did not capture a matching figure for the MX-13. Before you buy for heavy hauling, ask PACCAR or the dealer for the limit that applies to your exact setup.
- Service and warranty are the same on paper
- The two sheets list the same oil intervals, the same filter intervals and the same base and major-components warranty terms. So service cost and coverage should not decide between them. The design-life figure is the one difference: PACCAR prints a B10 for the MX-13 and none for the MX-11.
Put your MX-11 vs MX-13 service interval on a schedule with the maintenance scheduler. Decode warning lights with the fault code lookup. Before you buy a used truck, run the VIN decoder and used truck inspection checklist.
More engine comparisons and guides
Frequently Asked Questions
Is the MX-11 better than the MX-13?+
Neither is better on every job. PACCAR prints a design-life figure for the MX-13 and none for the MX-11, and there is no independent reliability study for either. The MX-11 is lighter. The MX-13 offers more power and torque. Pick by the rating you need and the weight you pull.
How much lighter is the MX-11 than the MX-13?+
PACCAR lists 2,200 lb dry for the MX-11 and 2,500 lb for the MX-13. That is 300 lb. PACCAR also says the MX-11 weighs 300 lb less than a 13-liter engine.
How much oil does each one take?+
PACCAR lists 39 U.S. quarts for the MX-11 and 42 U.S. quarts for the MX-13 as the oil system capacity.
Do the MX-11 and MX-13 have the same oil change interval?+
On PACCAR's sheets, yes. Both list 75,000 miles for line haul under 20% idle time, 50,000 miles over 20% idle, and 30,000 miles for severe or vocational duty. Idle percentage is the deciding factor, so check your own number.
Sources
Choosing between MX-11 vs MX-13? Let a dispatcher help.
Grow Trucking finds loads, negotiates rates and does the paperwork for owner-operators and small fleets. Tell us what you haul and we will show you how a MX-11 vs MX-13 truck fits the lanes we book.
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Specs, intervals and warranty terms for the MX-11 vs MX-13 engines change by model year and configuration. Power and torque ranges are from our engine reference. Confirm exact figures for a specific truck against the manufacturer's current documentation and your written warranty before buying or setting a service schedule.
Free tools for a MX-11 vs MX-13 decision
Decode fault codes for the MX-11 vs MX-13 engines, keep service on schedule and check a truck before you buy.
- Diesel Fault Code Lookup (SPN/FMI)Decode the SPN/FMI fault codes either MX-11 vs MX-13 engine reports.
- Preventive Maintenance SchedulerTrack oil and filter intervals for a MX-11 vs MX-13 truck by odometer and duty cycle.
- Breakdown Cost EstimatorEstimate what a breakdown costs in repairs and lost revenue on a MX-11 vs MX-13 truck.
- Truck Breakdown TriageIf a MX-11 vs MX-13 engine shows a red lamp or overheats, see if you should stop now.