2022 Chevrolet Silverado 3500HD Coolant Capacity & Type

The 2022 Chevrolet Silverado 3500HD holds between 17.4 and 32.7 quarts (16.5 to 31.0 liters) of coolant, depending on whether it is equipped with the 6.6L V8 gas engine or the 6.6L Duramax V8 turbo-diesel engine. As an ASE-certified master technician, I regularly service the cooling systems on these heavy-duty workhorses. Proper cooling system maintenance is essential, especially when you are towing heavy loads or operating in extreme temperatures. Below is your complete reference guide for servicing the cooling system on your 2022 Silverado 3500HD.

Quick answer

• Total cooling system capacity: 17.4 to 32.7 quarts (16.5 to 31.0 L), depending on the engine.
• OEM coolant spec: DEX-COOL® (Orange in color). This is an OAT (Organic Acid Technology) coolant meeting GM specification GMW3420.
• Mix ratio: 50/50 mixture of clean, drinkable water (preferably distilled or deionized) and DEX-COOL concentrate. Pre-mixed 50/50 DEX-COOL is also perfectly acceptable and convenient.

Capacity by engine option

Because the 3500HD features two vastly different powertrains, the coolant capacities vary significantly. The Duramax diesel has a massive cooling system to manage the heat generated by the engine, the turbocharger, and the heavy loads it is designed to pull.

Note: Capacities are approximate. Always verify fluid levels via the surge tank dipstick or MAX/MIN lines after a complete warm-up and cool-down cycle.

Flush interval

General Motors uses extended-life coolant in the Silverado 3500HD, but "extended life" doesn't mean "lifetime."

• Normal Duty: Replace the coolant every 150,000 miles or 5 years, whichever comes first.
• Severe Duty: If you are frequently towing heavy trailers, operating in severe dust, or idling for extended periods (common in fleet and hotshot trucking), it is highly recommended to inspect the coolant for degradation and perform a flush closer to 75,000 miles or every 5 years.

How to refill & bleed

Modern heavy-duty trucks have complex cooling systems with multiple heater cores, EGR coolers (on the diesel), and complex routing. Trapped air can cause localized overheating and catastrophic engine damage.

1. Drain the system: With the engine cold, locate the radiator drain petcock at the bottom corner of the radiator. Drain the fluid into an appropriately sized catch pan (remember, the diesel holds over 8 gallons!).
2. Vacuum Fill (Highly Recommended): For the 2022 Silverado 3500HD, utilizing a vacuum coolant refill tool (like an AirLift) is the best way to prevent air pockets. Attach the tool to the surge tank, draw a vacuum on the system, and allow the vacuum to pull the fresh 50/50 DEX-COOL mix into the block and radiator.
3. Manual Bleed (If vacuum fill is unavailable): Fill the surge tank slowly to the cold fill line. Leave the cap off. Start the engine and turn the cabin heater to maximum heat and blower.
4. Warm-up: Allow the engine to idle until the thermostat opens (the upper radiator hose will become hot). You will see the coolant level drop in the surge tank as air burps out. Add coolant as necessary.
5. Final Check: Install the cap, take the truck for a short test drive, and let it cool down completely. Check the cold level again and top off if necessary.

Common cooling system issues

While the 2022 Silverado 3500HD is generally robust, a few issues can crop up in this generation of GM heavy-duty trucks:

• Surge Tank Cracks: Over time, the pressurized plastic surge tank (coolant reservoir) can develop hairline cracks along the seams, leading to slow coolant leaks and pressure loss.
• Radiator End Tank Leaks: The factory radiators use aluminum cores crimped to plastic end tanks. Under heavy thermal cycling, the crimp seals can weaken, leading to minor weeping on the sides of the radiator.
• Water Pump Weep Hole Leaks: Particularly on the Duramax, keep an eye on the water pump weep hole. A small amount of dried orange crust over tens of thousands of miles is normal, but active dripping indicates an impending seal failure.

Proper maintenance is the key to keeping your truck on the road and out of the bay. If you aren't comfortable tackling a massive 8-gallon coolant flush yourself, leave it to the pros. Find a trusted shop on Repairius.