2025 Ram 2500: Coolant Capacity & Type

The 2025 Ram 2500 cooling system holds between 16 and 28 quarts (15.1 and 26.5 liters) of coolant, depending on the engine.

Quick Answer

• Total Cooling System Capacity: 16–28 qts (15.1–26.5 L), depending on engine.
• OEM Coolant Specification: Mopar 10-Year/150,000-Mile OAT (Organic Acid Technology) Coolant, dyed purple. The official Mopar specification is MS-12106.
• Mix Ratio: 50/50 mix of coolant concentrate and distilled water. Pre-mixed versions are recommended for convenience and accuracy.

Capacity by Engine Option

The 2025 Ram 2500 is available with two engine options, each having a different cooling system capacity.

Note: Capacities are approximate and can vary slightly. Always verify by checking the owner's manual or service information for your specific vehicle configuration.

Flush Interval

Following the factory-recommended service interval is critical for maintaining the health of your engine's cooling system.

• Normal Service: Mopar OAT coolant is designed for a long service life, with the first flush recommended at 10 years or 150,000 miles, whichever comes first.
• Severe Duty Service: If the vehicle is used for frequent towing, heavy hauling, extensive idling, or operating in extreme temperatures, it's wise to consider a shorter interval, such as every 5 years or 100,000 miles.

How to Refill & Bleed

Refilling and bleeding the cooling system on a 2025 Ram 2500, especially the Cummins diesel, requires care to avoid air pockets that can cause overheating.

1. Mix Coolant: If using concentrate, mix it 50/50 with distilled water in a clean container.
2. Slow Fill: Add the coolant slowly to the coolant reservoir (deaeration bottle). Do not fill directly into the radiator.
3. Bleeding (6.4L HEMI): This engine may have a bleeder screw on the thermostat housing. Loosen it during the fill process until a steady stream of coolant emerges, then tighten it.
4. Bleeding (6.7L Cummins): These engines are known for being difficult to bleed completely without special equipment. A vacuum-fill tool is highly recommended. This tool pulls the entire cooling system into a deep vacuum and uses that vacuum to draw coolant in, preventing any air from being trapped.
5. Run and Check: Start the engine with the heater on high. Let it run for several minutes to circulate the coolant. Monitor the temperature gauge. As the thermostat opens, the coolant level may drop. Top off the reservoir as needed to the "MAX" line.

Common Cooling System Issues

The 2019+ Ram HD platform is robust, but like any vehicle, it has potential weak points.

• Water Pump Failure: Particularly on the Cummins engine, water pumps are a common replacement item. Watch for coolant drips from the front of the engine or a "wobble" in the water pump pulley.
• Radiator Leaks: Leaks can develop from the seams where the plastic end tanks are crimped to the aluminum core, often caused by the constant heating and cooling cycles.
• EGR Cooler Issues (Cummins): The EGR (Exhaust Gas Recirculation) cooler can fail internally, causing coolant to be consumed by the engine. This may present as unexplained coolant loss without any visible external leaks.

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