2023 GMC Yukon — Coolant Capacity & Type

The 2023 GMC Yukon holds between 14.8 and 17.4 quarts (14.0 to 16.5 liters) of engine coolant, depending on the engine option under the hood and whether the vehicle is equipped with the rear heating system. As an ASE-certified master technician, I regularly service the cooling systems on GM’s full-size SUVs, and using the correct fluids and procedures is absolutely critical to keeping your Yukon on the road.

Quick answer

• Total cooling system capacity: 14.8 to 17.4 quarts (14.0 to 16.5 L), varying by engine and rear HVAC configuration.
• OEM coolant spec: AC Delco DEX-COOL (Orange color, Organic Acid Technology / OAT chemistry, GM specification GMW3420).
• Mix ratio: 50/50 mixture of DEX-COOL concentrate and clean, drinkable water (or distilled/deionized water), though 50/50 pre-mixed DEX-COOL is the easiest and most common way to top off. In extreme cold climates (below -34°F), a 60/40 coolant-to-water ratio may be required.

Capacity by engine option

Because the 2023 GMC Yukon is a massive three-row SUV, it comes standard with front and rear climate control. The capacities below reflect systems with the rear heater core factored in.

Note: Capacities are approximate. Vehicles equipped with the Max Trailering Package may feature high-capacity radiators, putting them at the higher end of the capacity range.

Flush interval

General Motors uses extended-life coolant, but it does not last forever.

• Normal Duty: Replace the coolant every 150,000 miles or 5 years, whichever comes first.
• Severe Duty: If you frequently tow heavy loads, idle extensively (like a fleet or livery vehicle), or drive in extreme heat or dusty conditions, inspect the coolant at 45,000-mile intervals and consider replacing it closer to the 100,000-mile or 4-year mark. If the orange coolant ever appears muddy, brown, or has floating debris, it must be flushed immediately.

How to refill & bleed

The long heater hoses running to the rear of the Yukon make bleeding air from the cooling system notoriously difficult using old-school methods. An air pocket can cause erratic heater performance or catastrophic engine overheating.

1. Drain the system: With the engine completely cold, open the radiator drain petcock.
2. Use a Vacuum Fill Tool (Highly Recommended): Because of the rear heater lines, ASE technicians heavily rely on pneumatic vacuum-fill tools (like an Airlift). This pulls the system into a deep vacuum, testing for leaks, and sucks the new DEX-COOL in without introducing a single air bubble.
3. Manual Bleed (If vacuum fill is unavailable): Fill the surge tank slowly to the cold fill line. Leave the cap off.
4. Turn the vehicle on and set the climate control to maximum heat for both the front and rear zones.
5. Allow the engine to idle until it reaches operating temperature and the thermostat opens.
6. Gently rev the engine to 2,000 - 2,500 RPM in short bursts to force trapped air through the lines.
7. Top off the surge tank as the fluid level drops. Once the heat blows consistently hot from both front and rear vents and the level stabilizes, install the cap. Recheck the cold fluid level after a few drive cycles.

Common cooling system issues

While the 2023 Yukon is quite new, it shares its engine architecture with previous years of the current generation. Common things to watch out for include:

• Water Pump Weep Hole Leaks: On the 5.3L and 6.2L V8s, water pumps will occasionally begin seeping coolant from the weep hole as the internal seal degrades.
• Thermostat Housing Seepage: The plastic thermostat housings can warp slightly over thousands of heat cycles, causing a slow, crusty orange leak.
• Heater Hose Connectors: The quick-connect fittings at the firewall for the heater core lines become brittle over time and can snap if bumped during other engine repairs.

Find a trusted shop on Repairius.