2016 Chevrolet Silverado 3500HD — Coolant Capacity & Type

The 2016 Chevrolet Silverado 3500HD holds between 16.7 quarts (15.8 liters) and 25.4 quarts (24.0 liters) of coolant, depending on whether it is equipped with the 6.0L gas V8 or the 6.6L Duramax diesel engine. As an ASE-certified master technician, I regularly service these heavy-duty trucks, and keeping the cooling system in top shape is critical, especially if you are towing heavy loads or operating in extreme temperatures.

Below is your comprehensive guide to the coolant capacity, specifications, and maintenance procedures for the 2016 Silverado 3500HD.

Quick answer

When it's time to top off or flush the cooling system in your 2016 Silverado 3500HD, here is exactly what you need to know:

• Total Cooling System Capacity: 16.7 to 25.4 quarts (15.8 to 24.0 liters), depending on the engine and auxiliary heating options.
• OEM Coolant Spec: DEX-COOL® (Orange). This is an Organic Acid Technology (OAT) coolant meeting General Motors specification GMW3420.
• Mix Ratio: A 50/50 mixture of DEX-COOL concentrate and clean, drinkable water (preferably distilled or deionized). Do not use a standard green IAT coolant, as mixing coolant types will cause sludge and system failure.

Capacity by engine option

Because the 3500HD was offered with two vastly different powertrains, the coolant capacities differ significantly. Keep in mind that trucks equipped with auxiliary rear heaters or dual alternators may hold slightly more coolant.

Note: Always buy an extra gallon of pre-mixed coolant when performing a full flush to account for system variations and bleeding.

Flush interval

General Motors specifies a standard coolant flush interval for the 2016 Silverado 3500HD of 150,000 miles or every 5 years, whichever comes first.

However, for a heavy-duty truck often subjected to "severe duty" (frequent towing, idling, or driving in dusty/extreme climates), it is highly recommended to inspect the coolant's freeze point and pH levels every 30,000 miles. Many diesel technicians prefer dropping the flush interval down to 100,000 miles or 4 years under severe usage to protect expensive components like the EGR cooler and water pump from corrosion.

How to refill & bleed

Refilling a heavy-duty truck, particularly the Duramax diesel, requires patience to prevent air pockets that can cause catastrophic overheating.

1. Drain the system: Locate the radiator petcock at the bottom of the radiator. For a complete flush, engine block drain plugs should also be removed.
2. Fill the system: Close all drains. Slowly pour the 50/50 DEX-COOL mix into the coolant surge tank until it reaches the "COLD FILL" line.
3. Bleed the Duramax (LML): If you have the 6.6L diesel, there is a dedicated bleeder screw located on the thermostat housing. Open this screw slightly while filling the system until a steady stream of coolant (without air bubbles) comes out, then tighten it.
4. Run and burp: Leave the surge tank cap off. Start the engine and let it idle until it reaches normal operating temperature and the thermostats open (you will feel the upper radiator hose get hot).
5. Top off: As the system burps air, the coolant level in the surge tank will drop. Top it back up to the cold fill line and securely install the cap.

Pro Tip: For the 6.6L Duramax, using a vacuum-fill tool (Airlift) is highly recommended. It pulls a vacuum on the entire cooling system, allowing you to draw the new coolant in without introducing any air pockets, saving a massive amount of bleeding time.

Common cooling system issues

The 2016 Silverado 3500HD is a workhorse, but its cooling system has a few known weak points for this generation:

• Duramax Water Pump Leaks: The LML Duramax water pump is known to fail and leak from the weep hole as the internal seal degrades. If you smell sweet coolant but don't see an obvious leak up top, inspect the water pump area.
• Surge Tank Cracking: The plastic coolant surge tank (expansion tank) undergoes continuous thermal cycling and can crack along the seams or at the hose fittings over time, leading to a slow, steady loss of coolant.
• EGR Cooler Leaks (6.6L Diesel): While less common on the LML than earlier generations, the EGR cooler can still develop internal cracks. This causes coolant to be burned in the exhaust, resulting in mysterious coolant loss and white smoke from the tailpipe.
• Radiator Crimps: The aluminum radiator core can sometimes separate from the plastic end tanks at the factory crimps, especially under heavy towing stress.

If you are dealing with a stubborn leak, overheating issues, or prefer to have a professional handle your 150k-mile flush, don't leave it to chance. Find a trusted shop on Repairius.