2020 Mercedes-Benz Sprinter — Coolant Capacity & Type

The 2020 Mercedes-Benz Sprinter holds between 9.5 and 12.0 quarts (9.0 to 11.4 liters) of coolant, depending on the engine equipped and whether your van features a rear auxiliary heating system. As an ASE-certified master technician, I regularly service these heavy-duty workhorses, and keeping up with the complex cooling systems on the modern Sprinter chassis is absolutely critical to engine longevity, especially for the diesel variants.

Quick answer

• Total cooling system capacity: 9.5 to 12.0 quarts (9.0 to 11.4 liters), varying primarily by engine size and climate control options (vans with rear passenger cabin heaters require more fluid).
• OEM coolant spec: Mercedes-Benz standard MB 325.6 (concentrate) or MB 326.6 (pre-mixed). This is a Pink/Magenta Si-OAT (Silicated Organic Acid Technology) coolant. Do not mix this with older blue or green coolants.
• Mix ratio: 50/50 blend of coolant and distilled water (if using concentrate), or use a pre-mixed 50/50 solution straight from the bottle.

Capacity by engine option

The exact amount of coolant your Sprinter needs will depend on the powerplant under the hood. Keep in mind that cargo vans with auxiliary rear heating loops will lean toward the higher end of these ranges.

Note: Always purchase at least three gallons of 50/50 mix if you are doing a completely dry fill after a flush or major component replacement.

Flush interval

Modern Mercedes-Benz Si-OAT coolants are incredibly robust, but they still degrade over time, losing their anti-corrosion and anti-cavitation properties.

• Normal Duty: Mercedes-Benz recommends a coolant replacement interval of 150,000 miles or 15 years, whichever comes first.
• Severe Duty: Most Sprinters are used for heavy towing, constant stop-and-go delivery routes, or high-idle operations. Under these severe conditions, I strongly recommend flushing the system every 100,000 miles or 10 years to protect the water pump and EGR coolers.

How to refill & bleed

The modern Sprinter cooling system is notoriously difficult to bleed manually. Because of the complex routing of coolant lines to the turbocharger, EGR cooler, and cabin heaters, air pockets are a major risk.

1. Drain the system: With the engine cold, remove the reservoir cap and open the petcock at the bottom corner of the radiator.
2. Pull a vacuum (Highly Recommended): I strongly advise using a pneumatic vacuum coolant filler tool. Attach the tool to the coolant reservoir, pull a vacuum on the system (into the green zone on the gauge), and hold it to check for leaks.
3. Draw in the new coolant: Open the valve on your vacuum tool to draw the 50/50 Si-OAT mixture directly into the system. This prevents air pockets from forming in the EGR cooler and heater core.
4. Final bleed: If you do not have a vacuum tool, fill the reservoir slowly. Turn the ignition on (engine off), turn the heater to max heat and low fan to open the heater valves. Start the engine and let it idle up to operating temperature. Keep a close eye on the reservoir and top off as the thermostat opens.
5. Test drive: Drive the van under load, let it cool completely overnight, and top off the reservoir to the "MAX" line the next morning.

Common cooling system issues

For the 2020 generation (VS30 chassis), there are a few cooling system quirks you should watch out for:

• EGR Cooler Leaks (3.0L Diesel): The OM642 diesel engine can develop internal leaks in the EGR cooler. If you are slowly losing coolant but don't see drips under the van, the coolant may be getting burned in the exhaust via the EGR system.
• Water Pump Weepage: The mechanical water pumps on these engines can develop slow leaks around the weep hole or the main gasket as they approach the 100k-mile mark.
• Coolant Level Sensor Failures: The sensor inside the plastic expansion tank is prone to sticking or failing, triggering a false "Low Coolant" warning on the dash even when the tank is full. Usually, the entire reservoir must be replaced to fix this.

If you suspect a leak or need a professional coolant flush using the proper vacuum equipment, don't put it off. Find a trusted shop on Repairius.