2020 Ram ProMaster Coolant Capacity & Type Guide

The 2020 Ram ProMaster with the standard 3.6L Pentastar V6 engine holds approximately 10.5 quarts (9.9 liters) of engine coolant. Keeping your commercial van’s cooling system in top shape is critical for preventing costly downtime and catastrophic engine failure. As an ASE-certified master technician, I have serviced countless fleet vehicles, and using the correct fluids and bleed procedures on the ProMaster is essential for long-term reliability.

Quick answer

When servicing the cooling system on your 2020 Ram ProMaster, keep these exact specifications in mind:

• Total Cooling System Capacity: Approximately 10.5 quarts (9.9 liters).
• OEM Coolant Spec: Mopar 10-Year/150,000-Mile Formula OAT (Organic Additive Technology). It must meet Chrysler material standard MS-12106. The factory coolant color is Purple.
• Mix Ratio: 50/50 mixture of concentrated coolant and distilled water, or a pre-mixed 50/50 OAT solution. Never use tap water, as the minerals will cause internal scaling and corrosion.

Capacity by engine option

For the 2020 model year, Ram streamlined the ProMaster lineup (excluding the smaller ProMaster City) to feature a single, robust powertrain.

Note: Capacities are approximate. When performing a drain and fill, you may not remove the entire 10.5 quarts due to coolant trapped in the heater core and engine block.

Flush interval

The factory-fill Mopar OAT coolant is designed for extended life, but commercial vans often see much harsher conditions than passenger vehicles.

• Normal Duty: Replace the coolant every 10 years or 150,000 miles, whichever comes first.
• Severe Duty: If your ProMaster is used for heavy towing, constant stop-and-go delivery routes, or idles for extended periods, I highly recommend flushing the system every 5 years or 100,000 miles to prevent acidic degradation of the fluid.

How to refill & bleed

The 3.6L Pentastar engine is notorious for trapping air in the cooling system, which can lead to localized overheating and erratic heater performance. While a vacuum-fill tool is the industry standard and highly recommended for this vehicle, here is the manual bleed procedure:

1. Locate the bleeder valve: Find the small bleeder screw on top of the thermostat housing.
2. Open the bleeder: Loosen the screw slightly before adding new coolant.
3. Fill the system: Slowly pour your 50/50 OAT coolant mix into the coolant reservoir until a steady, bubble-free stream of fluid weeps from the bleeder valve.
4. Close the valve: Snug the bleeder screw down (do not overtighten, as the plastic housing cracks easily).
5. Warm up the engine: Leave the reservoir cap off. Start the engine and turn the cabin heater to the maximum heat setting.
6. Bleed remaining air: Let the engine reach operating temperature so the thermostat opens. Top off the reservoir as the fluid level drops, squeezing the upper radiator hose to help force out stubborn air pockets.
7. Final check: Once the cooling fans cycle on and you have hot air blowing from the cabin vents, reinstall the reservoir cap and test drive. Check the level again once the engine is completely cold.

Common cooling system issues

The 2020 Ram ProMaster is a heavy-duty workhorse, but its 3.6L Pentastar V6 shares a few known cooling system vulnerabilities with other Chrysler/Dodge/Jeep vehicles:

• Oil Filter Housing / Oil Cooler Leaks: This is by far the most common issue on the 3.6L engine. The plastic oil filter housing sits in the valley of the engine block and incorporates an oil cooler. Over time, the plastic warps or the O-rings fail, causing coolant and oil to pool in the engine valley and run down the back of the bell housing.
• Thermostat Housing Cracks: The plastic thermostat housing can become brittle from constant heat cycling, leading to hairline cracks and slow coolant seepage.
• Radiator End Tank Seepage: On high-mileage delivery vans, the crimped seams where the plastic radiator end tanks meet the aluminum core are prone to weeping under pressure.

If you suspect a coolant leak or need a professional flush, don't leave your work van out of commission. Find a trusted shop on Repairius.