2023 Peterbilt 579 Coolant Capacity & Type

The 2023 Peterbilt 579 typically holds between 60 to 75 quarts (57 to 71 liters) of coolant in its cooling system, though capacity can vary based on engine and specific configuration.

Quick Answer

• Total Cooling System Capacity: 60-75 quarts (57-71 liters) (ranges based on engine and configuration)
• OEM Coolant Spec: Heavy-Duty, Extended Life Coolant (ELC) – typically a red/purple or pink Nitrited Organic Acid Technology (NOAT) or OAT formulation. Peterbilt recommends coolants meeting Cummins CES 14603 or RP 329, RP 338 standards.
• Mix Ratio: 50/50 prediluted or 50% coolant concentrate with 50% distilled water.

Capacity by Engine Option

The Peterbilt 579 can be equipped with various engines, and each will have a slightly different cooling system capacity. It is crucial to consult your owner's manual or the engine manufacturer's specifications for the precise capacity for your specific vehicle.

Note: These are approximations. Always refer to your Peterbilt 579 owner's manual for exact capacities.

Flush Interval

For a 2023 Peterbilt 579, the coolant flush interval largely depends on the coolant type used and operating conditions.

• Normal Duty: With an Extended Life Coolant (ELC) compliant with Peterbilt/PACCAR or Cummins specifications, the typical flush interval can be as long as 600,000 miles (965,000 km), 12,000 hours, or 6 years, whichever comes first.
• Severe Duty: For vehicles operating under severe conditions (e.g., heavy hauling, extreme temperatures, dusty environments), it's wise to inspect the coolant and Drip (Depletion Reserve Inhibitor Package) levels more frequently and consider reducing the flush interval by 25-50%.

Always monitor coolant condition and maintain proper Drip levels (if applicable for your ELC type), using test strips to ensure adequate additive protection.

How to Refill & Bleed

Refilling and bleeding the cooling system on a heavy-duty truck like the Peterbilt 579 requires care to prevent air pockets, which can lead to overheating. Always perform this procedure on a cool engine.

1. Drain Old Coolant: Safely drain the old coolant into an appropriate container for recycling. This typically involves opening the radiator drain cock and potentially engine block drain plugs.
2. Flush (Optional but Recommended): If performing a full flush, refill the system with distilled water (or a cooling system flush product per instructions), run the engine to operating temperature with the heater on, then drain again. Repeat until the water runs clear.
3. Refill with New Coolant: Close all drain points. Begin refilling the system slowly through the surge tank or radiator fill neck with the specified 50/50 prediluted ELC. If using concentrate, pre-mix with distilled water before adding.
4. Bleeding Procedure:
   • Leave the surge tank cap off. Start the engine and run it at a fast idle (around 1000-1200 RPM).
   • Turn the cab heater to full hot and fan on high to open the heater core. This helps purge air from the heater circuit.
   • As the engine warms and the thermostat opens, the coolant level in the surge tank will drop. Continuously top it off to the