2020 Peterbilt 579 Oil Capacity & Filter Reference

The 2020 Peterbilt 579 with the PACCAR MX-13 engine requires 44 quarts (41.6 liters) of 15W-40 CJ-4 or CK-4 heavy-duty diesel engine oil. For the Cummins X15, the capacity is 11 gallons (41.6 liters) of the same 15W-40 oil.

Quick Answer: 2020 Peterbilt 579 Oil Service

• Oil Capacity (PACCAR MX-13): 44 quarts / 41.6 liters
• Oil Capacity (Cummins X15): 11 gallons / 41.6 liters
• Recommended Oil Weight: 15W-40 or 5W-40 Synthetic
• Oil Specification: API Service CK-4 or CJ-4
• Oil Filter (PACCAR MX-13 OEM): LF667
• Oil Filter Cross-Reference: Fleetguard LF16035, Baldwin B7379
• Oil Filter (Cummins X15 OEM): Fleetguard LF14000NN
• Oil Filter Cross-Reference: Fram CH11816, Wix WL10103

Capacity by Engine Option

Oil Change Interval

The oil change interval on a 2020 Peterbilt 579 depends heavily on the application, idle time, and fuel consumption. The truck's onboard computer will provide the most accurate interval based on real-world use.

• Normal Duty: For long-haul applications with minimal idle time, the interval can be as high as 60,000 miles, as determined by the oil analysis program and onboard diagnostics.
• Severe Duty: For vocational use, heavy hauling, or high-idle-time applications, the interval is typically much shorter, often in the 25,000 to 35,000-mile range. Always refer to the engine manufacturer's guidelines and your fleet's preventive maintenance schedule.

Drain Plug Torque

Proper torque on the oil drain plug is critical to prevent leaks and stripped threads on the large-capacity oil pan.

• PACCAR MX-13 Drain Plug Torque: 63 ft-lbs (85 Nm).
• Cummins X15 Drain Plug Torque: 60 ft-lbs (81 Nm).
• Crush Washer: Always use a new crush washer with every oil change to ensure a proper seal.

How to Change the Oil

Changing the oil on a Peterbilt 579 is a straightforward but large-scale job.

1. Warm the engine to bring the oil to operating temperature.
2. Position a large-capacity oil drain pan (at least 15 gallons) under the oil pan drain plug.
3. Remove the drain plug and allow the oil to drain completely. This will take a significant amount of time.
4. While the oil is draining, locate and remove the oil filter canister or spin-on filter. Be prepared for additional oil spillage.
5. Install the new oil filter, making sure to lubricate the gasket with clean oil before installation.
6. Once the oil flow from the drain plug slows to a drip, clean the drain plug and the mating surface on the pan. Install a new crush washer.
7. Reinstall and torque the drain plug to specification.
8. Fill the engine with 44 quarts (11 gallons) of the correct specification oil.
9. Start the engine and let it run for a few minutes to circulate the new oil. Check for leaks at the drain plug and filter.
10. Shut the engine off, wait 15-20 minutes for the oil to settle, and then re-check the oil level via the dipstick, adding oil as necessary to reach the full mark.

Common Issues / Tips

• Oil Analysis is Key: For any fleet or owner-operator, a consistent oil analysis program is the best way to determine the true health of the engine and safely extend drain intervals. It provides invaluable data on wear metals and oil condition.
• Filter Quality Matters: Given the long service intervals and high cost of engine repair, always use high-quality OEM or reputable aftermarket filters. Cheap filters can lead to catastrophic engine failure.
• Resetting the Monitor: After the oil change is complete, be sure to reset the oil life monitor in the truck's information display. Failure to do so will result in inaccurate maintenance reminders.

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