2022 Chevrolet Silverado 2500HD — Coolant Capacity & Type

A 2022 Chevrolet Silverado 2500HD holds between 18.2 quarts and 29.8 quarts 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 a heavy-duty truck designed for extreme towing and hauling, the Silverado 2500HD relies on a massive, highly efficient cooling system to keep engine and transmission temperatures in check. Using the correct coolant specification and maintaining proper fluid levels is critical to preserving your engine's internal components.

Quick Answer

• Total Cooling System Capacity: 18.2 quarts (17.2 L) for the 6.6L gas engine; approximately 29.8 quarts (28.2 L) for the 6.6L Duramax diesel.
• OEM Coolant Spec: DEX-COOL® (Orange in color). This is an OAT (Organic Acid Technology) coolant meeting the GM 6277M / GMW3420 specification.
• Mix Ratio: 50/50 pre-mixed solution of DEX-COOL and clean, drinkable (preferably deionized or distilled) water. Extreme cold climates (below -34°F) may require a 60/40 mix, but never exceed 70% coolant concentrate.

Capacity by Engine Option

The 2022 Silverado 2500HD was offered with two powerhouse engine options, each with vastly different cooling system requirements. The Duramax diesel features a much larger capacity to support the heavy demands of the diesel combustion process, the turbocharger, and the charge air cooling circuit.

Note: Capacities are approximate and represent a completely dry system. A standard drain and fill will typically require less fluid.

Flush Interval

GM recommends changing the DEX-COOL coolant on the 2022 Silverado 2500HD at the following intervals to prevent corrosion and maintain heat transfer efficiency:

• Normal Duty: Flush and replace the coolant every 150,000 miles or 5 years, whichever comes first.
• Severe Duty: If you frequently tow heavy loads, idle extensively, or drive in high-dust/high-heat environments, mechanics highly recommend a flush interval of 75,000 to 100,000 miles or every 3 to 4 years.

How to Refill & Bleed

Modern heavy-duty cooling systems, particularly on the Duramax diesel, are highly complex and prone to trapping air. Air pockets can lead to localized overheating, EGR cooler damage, or false low-coolant warnings.

1. Drain the System: With the engine completely cold, place a large drain pan under the radiator drain petcock. Remove the surge tank cap and open the petcock to drain.
2. Use a Vacuum Fill Tool (Highly Recommended): Because the 6.6L Duramax has multiple cooling circuits (engine, heater core, EGR, and charge air cooler), a vacuum coolant filler is the only foolproof way to refill the system without trapping air. Connect the tool to the surge tank, pull a deep vacuum on the system, and allow the vacuum to draw the new 50/50 DEX-COOL mix into the truck.
3. Manual Bleed (If Vacuum Tool is Unavailable): If you must fill manually, pour the coolant slowly into the surge tank until it reaches the cold fill line. Start the engine and turn the heater to the maximum heat setting.
4. Burp the System: Let the engine idle with the surge tank cap off (or loosely installed) until the upper radiator hose gets hot, indicating the thermostat has opened. Watch the fluid level drop as air burps out, and add coolant as necessary.
5. Final Check: Reinstall the cap tightly. Test drive the vehicle, let it cool down completely, and top off the surge tank to the "COLD FILL" mark.

Common Cooling System Issues

While the 2022 generation of the Silverado 2500HD is incredibly robust, there are a few cooling system quirks and potential issues to keep an eye on as the miles rack up:

• Surge Tank Cracks & Leaks: The plastic coolant surge tank undergoes constant thermal cycling. Over time, micro-cracks can develop along the seams, causing slow coolant loss and a noticeable sweet smell under the hood.
• Coolant Contamination (Sludging): DEX-COOL OAT coolant does not play well with older IAT (green) coolants. If a previous owner or lube tech accidentally topped off the system with conventional "universal" green coolant, it can cause the DEX-COOL to gel and sludge, completely blocking the heater core and radiator.
• Water Pump Weepage: While improved over previous generations, the mechanical water pump on high-mileage 6.6L gas and diesel engines may begin to weep from the weep hole. Inspect the front of the engine for crusty orange residue during routine oil changes.
• EGR Cooler Leaks (Diesel): On the Duramax, an internal EGR cooler leak can consume coolant without any visible external drips. If you are losing coolant and noticing white smoke from the exhaust, the EGR cooler should be pressure tested.

Working on heavy-duty truck cooling systems can be messy and challenging without the right tools. If you suspect a leak or need a professional vacuum flush, don't leave it to chance. Find a trusted shop on Repairius.