2019 GMC Yukon Coolant Capacity, Type, and Maintenance Guide

The 2019 GMC Yukon holds between 17.4 and 18.1 quarts (16.5 to 17.1 liters) of coolant, depending on the engine and whether it is equipped with rear climate control or the Max Trailering Package. Maintaining the cooling system in your full-size SUV is critical to keeping that V8 engine running reliably, whether you are hauling the family or towing a heavy load.

Quick answer

• Total cooling system capacity: 17.4 to 18.1 quarts (16.5 - 17.1 L)
• OEM coolant spec: ACDelco Dex-Cool (Orange), OAT (Organic Acid Technology), GM specification GMW3420 (formerly GM6277M).
• Mix ratio: 50/50 mixture of Dex-Cool concentrate and clean, drinkable water (or use pre-mixed 50/50 Dex-Cool).

Capacity by engine option

The 2019 GMC Yukon (including the Yukon XL and Denali trims) features large V8 engines and a massive cabin, often requiring auxiliary rear heating circuits. Because of this, the total fluid capacity varies slightly depending on your exact configuration:

Note: Most 2019 Yukons come standard with rear climate control, so you should expect to use the higher capacity when doing a completely dry fill. Always buy a little extra.

Flush interval

General Motors uses Dex-Cool, which is a long-life OAT coolant. However, it still breaks down over time.

• Normal Duty: Replace the coolant every 150,000 miles or 5 years, whichever comes first.
• Severe Duty: If you frequently tow heavy trailers, idle for extensive periods, or drive in extreme heat or dusty conditions, it is highly recommended to flush the system every 100,000 miles or 4 years. Degraded Dex-Cool can turn sludgy, which restricts the heater core and radiator.

How to refill & bleed

The 2019 GMC Yukon uses a pressurized surge tank rather than a traditional radiator cap. To properly refill and bleed air from the system:

1. Preparation: Ensure the engine is completely cold. Place a drain pan under the radiator petcock.
2. Fill: Slowly pour your 50/50 Dex-Cool mixture into the surge tank until the fluid level reaches the "COLD FILL" mark.
3. Bleed the air: Leave the surge tank cap off. Start the engine and turn the climate control heaters (front and rear) to their maximum temperature settings with the blower on low.
4. Idle and observe: Let the engine idle. As the thermostat opens (you will feel the upper radiator hose get hot), the fluid level in the surge tank will likely drop as trapped air bubbles escape.
5. Top off: Add more coolant to keep it at the COLD FILL line. Once the level stabilizes and no more bubbles appear, securely tighten the surge tank cap.
6. Test drive: Take the vehicle for a short drive, let it cool down completely, and check the surge tank level one more time. Add coolant if necessary.

Pro-tip: Because of the rear heater core lines running the length of the vehicle, a vacuum-fill tool is highly recommended for this SUV. It pulls a vacuum on the system and sucks the coolant in, completely eliminating trapped air pockets in the rear lines.

Common cooling system issues

While the 2019 GMC Yukon's cooling system is generally robust, as an ASE-certified technician, I frequently see a few specific issues on this generation (2015-2020):

• Water Pump Failure: The mechanical water pump on the 5.3L and 6.2L engines is prone to leaking at the weep hole or experiencing bearing failure around the 80,000 to 100,000-mile mark. If you hear a chirping noise or see an orange puddle under the front center of the engine, check the water pump.
• Heater Hose Connectors: The plastic quick-connect fittings for the heater hoses near the firewall become brittle from heat cycling. They can snap suddenly, causing a rapid loss of coolant.
• Radiator Cracking: The plastic end tanks on the OEM radiator can develop hairline cracks, especially on the driver's side near the upper hose inlet.
• Sludge Buildup: If Dex-Cool is mixed with non-compatible green/yellow coolants or air is introduced into the system for long periods, it can gel up and clog the heater cores.

If you suspect a coolant leak or it's time for your 5-year flush, don't put it off. Find a trusted shop on Repairius.