2014 GMC Sierra 2500HD Coolant Capacity & Type

The 2014 GMC Sierra 2500HD has a total cooling system capacity of between 15.1 and 24.1 quarts (14.3 and 22.8 liters), depending on the engine option.

Quick Answer

• Total Cooling System Capacity: 15.1 qts (14.3 L) for the 6.0L V8 (L96); 24.1 qts (22.8 L) for the 6.6L Duramax Diesel V8 (LML).
• OEM Coolant Specification: GM DEX-COOL® (Orange, Organic Acid Technology - OAT).
• OEM Part Number(s): GM 12346290 / ACDelco 10-101.
• Mix Ratio: 50/50 mix of DEX-COOL® coolant and deionized water. It is commonly available as a pre-mixed solution.

Capacity by Engine Option

The 2014 Sierra 2500HD was available with two engine choices, which have significantly different cooling system capacities.

Flush Interval

Following the manufacturer's recommended service interval is critical for maintaining cooling system performance and preventing corrosion.

• Normal Service: General Motors recommends a coolant flush and replacement every 5 years or 150,000 miles, whichever comes first.
• Severe Duty Service: If the truck is used for frequent towing, hauling heavy loads, extensive idling, or operating in extreme temperatures, it is wise to consider a shorter interval, such as every 3 years or 60,000 miles.

How to Refill & Bleed

Properly refilling and bleeding the cooling system is essential to prevent air pockets, which can cause overheating and damage to engine components.

1. Mix Coolant: If using concentrate, mix it with deionized water to a 50/50 ratio in a clean container before adding it to the vehicle.
2. Slow Fill: Add the coolant slowly into the coolant reservoir (deaeration tank). Do not fill directly into the radiator.
3. Bleeding (6.0L Gas V8): This engine does not have a specific air bleed screw. The "spill-free" funnel method is highly recommended. Attach a large, no-spill funnel to the coolant reservoir, fill it partially, and run the engine with the heater on high. This will allow air to bubble out as the thermostat opens.
4. Bleeding (6.6L Duramax Diesel): The Duramax has a bleed screw located on the thermostat housing. After partially filling the system, loosen this screw until a steady stream of coolant appears, then tighten it. A vacuum-fill tool is the preferred professional method for this large system to ensure no air is trapped.
5. Top Off: After the engine has reached operating temperature and cooled down completely, re-check the coolant level in the reservoir and top off as needed to the "Full Cold" line.

Common Cooling System Issues

This generation of GMC Sierra HD trucks is generally reliable, but some common issues can arise:

• Water Pump Failure: The water pump is a common failure point on both the gas and diesel engines, often signaled by a coolant leak from the front of the engine or a whining/grinding noise.
• Radiator Leaks: The plastic end tanks crimped to the aluminum core of the radiator can develop leaks over time. Look for coolant residue or drips on or under the radiator.
• Thermostat Issues: A thermostat stuck open will cause the engine to be slow to warm up and result in poor heater performance. A thermostat stuck closed will lead to rapid overheating.
• Coolant Leaks at Hoses/Fittings: With age and mileage, rubber hoses can become brittle and plastic fittings can crack, leading to leaks. The radiator hoses and heater hoses are common culprits.

If you are experiencing any of these issues, it is best to have your vehicle inspected. Find a trusted shop on Repairius.