2019 Peterbilt 579 Coolant Capacity & Type

The 2019 Peterbilt 579 holds approximately 62-75 quarts (58.7-71.1 liters) of coolant, depending on the specific engine and cooling system configuration.

Quick Answer

• Total Cooling System Capacity: 62-75 quarts (58.7-71.1 liters)
• OEM Coolant Spec: Check engine manufacturer specifications (e.g., Cummins, PACCAR) for recommended ELC (Extended Life Coolant). Typically a red/purple or pink OAT (Organic Acid Technology) coolant meeting industry standards like ASTM D6210 or TMC RP-329.
• Mix Ratio: 50/50 prediluted, or 50% concentrate with 50% distilled water for optimal freeze protection and corrosion resistance.

Capacity by Engine Option

The 2019 Peterbilt 579 was available with several engine options, primarily from PACCAR and Cummins. Coolant capacities can vary based on the specific engine and radiator size.

Always consult your vehicle's owner's manual or the specific engine manufacturer's service literature for precise capacities.

Flush Interval

For most heavy-duty applications like the Peterbilt 579, adhering to regular coolant flush intervals is crucial for longevity and performance.

• Normal Duty: Typically, Extended Life Coolants (ELCs) can last for 600,000 miles, 12,000 hours, or 6 years, whichever comes first.
• Severe Duty (e.g., extreme temperatures, heavy hauling, frequent idling): Consider reducing the flush interval to 300,000 miles, 6,000 hours, or 3-4 years. It is recommended to perform regular testing of the coolant (e.g., every 100,000 miles or annually) to check for additive depletion and pH levels.

Regardless of the interval, always monitor coolant levels and condition, and address any signs of contamination or low levels promptly.

How to Refill & Bleed

Properly refilling and bleeding the cooling system on a heavy-duty truck like the Peterbilt 579 is essential to prevent air pockets, which can lead to overheating.

1. Drain the System: With the engine cool, open the petcocks on the radiator and engine block (if present) to completely drain the old coolant. Flush with distilled water until clear.
2. Close Drain Points: Once drained, close all petcocks securely.
3. Add New Coolant: Slowly add the correct ELC coolant mixture (50/50 prediluted or concentrate mixed with distilled water) to the surge tank or radiator fill neck.
4. Start Engine & Bleed: Start the engine and run it with the heater on high. This helps open the thermostat and circulate coolant through the heater core. Monitor the coolant level in the surge tank and top off as needed. Some systems may have air bleed valves or hoses that can be opened to release trapped air.
5. Check for Air Pockets: Continue running the engine until it reaches operating temperature. Squeeze the upper and lower radiator hoses to help dislodge air. The surge tank level should stabilize.
6. Final Check: Once the engine is cool, recheck the coolant level and top off if necessary. Monitor the coolant level over the next few driving cycles.

Some Peterbilt 579 models, especially those with larger engines, may benefit from a vacuum fill tool to ensure all air is removed effectively.

Common Cooling System Issues

Heavy-duty trucks like the 2019 Peterbilt 579 can experience several common cooling system issues, often exacerbated by the demands of commercial operation.

• Coolant Leaks: Due to the extensive plumbing, hoses, and connections, leaks are a common problem. Inspect the radiator, hoses, water pump, and heater core for signs of leakage.
• Water Pump Failure: The water pump is a critical component that circulates coolant. Wear and tear can lead to bearing failure or leaks from the weep hole.
• Radiator Clogging/Damage: Debris, corrosion, or external damage can clog or damage radiator fins, reducing cooling efficiency.
• Thermostat Issues: A stuck-open or stuck-closed thermostat can lead to the engine running too cold or overheating, respectively.
• EGR Cooler Leaks: For engines equipped with Exhaust Gas Recirculation (EGR) systems, the EGR cooler can be a source of coolant leaks, often leading to white smoke from the exhaust or coolant loss without external leaks.
• Coolant Degradation: Over time, coolant additives can deplete, leading to corrosion and cavitation. This emphasizes the importance of using the correct ELC and adhering to flush intervals.

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