2014 Peterbilt 579 Oil Capacity & Filter

The 2014 Peterbilt 579 with the PACCAR MX-13 engine requires 42 quarts (39.7 liters) of 15W-40 diesel engine oil. For the Cummins ISX15 engine, the capacity is 11 gallons (41.6 liters).

Quick Answer

• Oil Capacity (PACCAR MX-13): 42 quarts / 39.7 liters
• Oil Capacity (Cummins ISX15): 11 gallons / 41.6 liters
• Recommended Oil Weight: 15W-40 or 10W-30
• Oil Specification: API CJ-4 or CK-4
• Oil Filter (PACCAR MX-13 OEM): PACCAR 1898033PE
• Oil Filter Cross-Reference (MX-13): Wix WL10065, Fram XGA10460, Mobil 1 M1-702A
• Oil Filter (Cummins ISX15 OEM): Cummins LF9009
• Oil Filter Cross-Reference (ISX15): Wix 57746XD, Fram HPH9009, Mobil 1 M1-901

Capacity by Engine Option

Oil Change Interval

For a commercial vehicle like the 2014 Peterbilt 579, oil change intervals are heavily dependent on usage, fuel consumption, and idle time rather than just mileage. Always refer to your engine manufacturer's specific guidelines and consider using oil analysis to determine the optimal change interval.

• Normal Duty: For long-haul applications with minimal idling, an interval of 50,000 to 75,000 miles might be possible, especially when using high-quality CK-4 synthetic oils and extended-life filters. However, this requires careful monitoring and is at the upper end of the spectrum.
• Severe Duty: For vocational use, heavy hauling, frequent stop-and-go, high-idling applications, or use in extreme temperatures, a more conservative interval of 20,000 to 30,000 miles is recommended. If the truck is used for short hauls, construction, or other demanding tasks, even shorter intervals may be necessary.

Drain Plug Torque

The oil drain plug on both the PACCAR MX-13 and Cummins ISX15 should be torqued to 60 lb-ft (81 Nm). Always use a new crush washer or sealing washer to prevent leaks. Over-tightening can damage the threads on the oil pan, leading to a costly repair.

How to Change the Oil (Simplified)

1. Warm Up: Run the engine for a few minutes to warm the oil, which helps it drain more completely.
2. Position & Safety: Park the truck on a level surface and engage the parking brake. Chock the wheels for safety.
3. Drain: Place a large-capacity drain pan (at least 12-15 gallons) under the oil pan drain plug. Remove the plug and allow the oil to drain completely. This will take a significant amount of time due to the large volume.
4. Replace Filters: While the oil is draining, locate and remove the oil filters. There are typically two or three filters on these engines (a full-flow and a bypass filter). Make sure to have a catch pan underneath to handle spills. Lubricate the gasket of the new filters with fresh engine oil before spinning them on. Hand-tighten, then turn an additional three-quarters to one full turn as per the filter manufacturer's instructions.
5. Reinstall Plug: Once the oil flow has slowed to a drip, clean the drain plug and the mating surface on the oil pan. Install a new sealing washer and tighten the drain plug to 60 lb-ft.
6. Refill: Refill the engine with the correct specification and quantity of new oil. Start with about 90% of the capacity, then check the dipstick, adding as necessary to reach the full mark. Do not overfill.
7. Run & Check: Start the engine and let it run for a minute to circulate the new oil. Check for any leaks around the drain plug and filters. Shut off the engine, wait several minutes for the oil to settle, and re-check the dipstick, topping off if needed.

Common Issues & Tips

• Filter Confusion: The PACCAR MX-13 uses a specific cartridge-style filter that differs from the more common spin-on filters found on the Cummins. Ensure you have the correct housing cap O-rings and filter element for the job.
• Oil Sample Port: Many of these engines are equipped with an oil sample port (often a small valve on the filter housing). Use this to take a sample for oil analysis before draining the old oil. This data is invaluable for tracking engine health and optimizing drain intervals.
• Priming Filters: For the Cummins ISX, some technicians prefer to pre-fill the oil filters with new oil before installation to minimize the time the engine runs without full oil pressure upon startup. For the PACCAR MX-13's cartridge filter, this is not applicable.
• Resetting Maintenance Monitor: After the oil change, be sure to reset the oil life or maintenance monitor in the truck's information display. The procedure is typically found in the owner's manual.

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