2021 GMC Yukon — Coolant Capacity & Type

The 2021 GMC Yukon cooling system holds approximately 16.7 quarts (15.8 liters) of coolant for the 5.3L V8 engine and 17.1 quarts (16.2 liters) for the 6.2L V8 engine.

Quick Answer

• Total Cooling System Capacity (5.3L V8): Approximately 16.7 quarts (15.8 liters)
• Total Cooling System Capacity (6.2L V8): Approximately 17.1 quarts (16.2 liters)
• OEM Coolant Spec: DEX-COOL (Orange/Pink, OAT - Organic Acid Technology), meets GM Standard GMW3420
• Mix Ratio: 50/50 Pre-mix or 50/50 concentrate with distilled water

Capacity by Engine Option

Flush Interval

For the 2021 GMC Yukon, the recommended coolant flush interval is generally every 150,000 miles or 5 years, whichever comes first, under normal driving conditions. If your vehicle experiences severe duty (e.g., frequent towing, extreme temperatures, off-road driving), it's advisable to inspect your coolant more frequently and consider shortening the flush interval to ensure optimal cooling system performance.

How to Refill & Bleed

Refilling and bleeding the cooling system on a 2021 GMC Yukon is crucial to prevent air pockets, which can lead to overheating. Here's a general procedure:

1. Ensure Engine is Cool: Never open the cooling system when the engine is hot.
2. Drain Old Coolant (if flushing): Use the petcock on the bottom of the radiator to drain the old coolant into a suitable container. Dispose of used coolant responsibly.
3. Refill with New Coolant: Slowly pour the new 50/50 DEX-COOL mixture into the coolant reservoir up to the "COLD FILL" line.
4. Start Engine and Bleed: Start the engine with the heater on full blast (hot) and the fan on low. This helps open the heater core and circulate coolant. Allow the engine to reach operating temperature.
5. Burp the System: As the engine warms up, air bubbles will escape through the coolant reservoir. Squeeze the upper and lower radiator hoses a few times to help dislodge trapped air. Keep an eye on the coolant level and top off as needed.
6. Check for Bleed Screws (if applicable): Some engines may have a bleed screw on the thermostat housing or another high point in the system. Consult your service manual to see if your specific engine has one and how to use it.
7. Drive and Recheck: After a drive cycle, allow the engine to cool completely and recheck the coolant level in the reservoir. Top off if necessary.

Note: For a more thorough and professional bleeding, a vacuum fill tool can be used to evacuate all air from the system before refilling.

Common Cooling System Issues for this Generation

While the 2021 GMC Yukon is a relatively new vehicle, some common cooling system considerations related to the underlying GM platforms and engines include:

• Coolant Leaks: Keep an eye out for tell-tale pink or orange stains under your vehicle, which can indicate a coolant leak from hoses, the radiator, water pump, or reservoir. Look closely around hose connections, the radiator end tanks, and the water pump assembly.
• Water Pump Failure: Although less common on newer vehicles, water pump issues can occur, leading to leaks, noise, and eventually overheating. Listen for grinding noises from the front of the engine.
• Thermostat Issues: A malfunctioning thermostat can lead to the engine running too hot or too cold. Symptoms include erratic temperature gauge readings or poor heater performance.
• Radiator/Heater Core Clogging: Over time, especially if incompatible coolants are mixed or maintenance is neglected, deposits can build up in the radiator and heater core, reducing their efficiency. This can lead to reduced heating in the cabin or overheating.

Regular coolant checks and adherence to the recommended service intervals are key to preventing these issues and ensuring the longevity of your 2021 GMC Yukon's cooling system.

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