2017 GMC Sierra 1500 Coolant Capacity, Type & Maintenance Guide

The 2017 GMC Sierra 1500 holds between 15.7 and 17.5 quarts of coolant, depending on the exact engine equipped in your truck. Maintaining the cooling system on these third-generation Sierra trucks (part of the K2XX platform) is crucial to keeping those powerful EcoTec3 engines running efficiently, especially if you use your truck for heavy towing or hauling.

As an ASE-certified master technician, I regularly see these trucks in the shop for routine maintenance and cooling system services. Below is a comprehensive guide to the coolant capacity, type, and maintenance procedures for the 2017 GMC Sierra 1500.

Quick answer

• Total Cooling System Capacity: 15.7 to 17.5 quarts (14.9 to 16.6 liters), depending on the engine.
• OEM Coolant Spec: DEX-COOL® (Orange in color). This is an OAT (Organic Acid Technology) coolant meeting the GM6277M specification.
• Mix Ratio: 50/50 pre-mixed solution of DEX-COOL and clean, drinkable water (deionized or distilled water is highly recommended if mixing from concentrate). For extremely cold climates (below -34°F / -37°C), a 60/40 mix of coolant to water can be used, but never exceed 70% coolant.

Capacity by engine option

The 2017 GMC Sierra 1500 was offered with three different EcoTec3 engines. The coolant capacity varies based on the block size and cooling system demands.

Note: Capacities are approximate and can vary slightly if the vehicle is equipped with a heavy-duty trailering package or auxiliary transmission/oil coolers. Always use the surge tank dipstick or cold-fill lines to verify final levels.

Flush interval

Keeping fresh DEX-COOL in your Sierra is vital because OAT coolants lose their anti-corrosion properties over time.

• Normal Duty: GM recommends flushing and replacing the cooling system fluid every 150,000 miles or 5 years, whichever comes first.
• Severe Duty: If you frequently tow heavy loads, idle extensively (like in fleet use), or drive in extremely hot dusty climates, I recommend inspecting the coolant at 50,000 miles and performing a flush every 100,000 miles or 4 years. Degraded coolant will turn muddy or dark and can clog the heater core.

How to refill & bleed

The Gen-V GM V8 and V6 engines use a pressurized surge tank. Bleeding these systems can sometimes be tricky due to the routing of the heater hoses.

1. Drain: Ensure the engine is completely cold. Open the radiator petcock (if equipped) or remove the lower radiator hose to drain the old coolant.
2. Vacuum Fill (Recommended): Because these trucks are prone to trapping air in the heater core and cylinder heads, using a pneumatic vacuum coolant filler is the professional standard. It pulls a vacuum on the entire system and sucks the 50/50 mix in without introducing any air pockets.
3. Manual Refill (If vacuum tool is unavailable):
   • Slowly pour the 50/50 DEX-COOL mix into the surge tank until it reaches the "COLD FILL" line.
   • Leave the cap off. Start the engine and turn the cabin heater to the maximum heat setting and the blower on low.
   • Let the engine idle until the thermostat opens (you will feel the upper radiator hose get hot).
   • As the coolant level drops in the surge tank, continue topping it off to the cold fill line.
   • Once the level stabilizes and hot air blows from the cabin vents, install the pressure cap tightly.
4. Final Check: Shut off the engine, let it cool completely, and re-check the cold fill line. Top off as necessary.

Common cooling system issues

The 2017 Sierra is generally reliable, but there are a few cooling system quirks you should watch out for:

• Water Pump Failures: The mechanical water pumps on the 5.3L and 6.2L engines are known to develop leaks at the weep hole as the internal seal wears out. If you smell sweet coolant but don't see a puddle, check behind the water pump pulley.
• Thermostat Housing Leaks: The gasket mating the thermostat housing to the water pump can degrade and cause slow coolant loss.
• Radiator End Tank Seepage: Like many modern trucks, the aluminum radiator core is crimped to plastic end tanks. Over time, heat cycling can cause the plastic-to-metal crimp seal to leak.
• Heater Core Clogs: Mixing standard green IAT coolant or universal coolants with DEX-COOL can cause the fluid to gel, which frequently clogs the heater core and destroys cabin heating performance. Only use DEX-COOL!

If you suspect a leak, a pressure test of the cooling system at 15-18 psi is the best way to pinpoint the issue.

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