Coolant Flush How-to: 2018 GMC Sierra 3500 HD SLE 6.0L V8 Crew Cab Pickup

Learn how to flush the coolant (antifreeze) in your 2018 GMC Sierra 3500 HD. Coolant / antifreeze circulates through Sierra 3500 HD radiator and engine to maintain the proper temperature. Coolant / antifreeze also passes through the heater core under your cowl to provide heat to the cabin of your Sierra 3500 HD. In addition to preventing your car from overheating, coolant / antifreeze also helps lubricate the seals in the water pump and hoses. Start your coolant flush by draining the coolant / antifreeze that is in your reservoir, then drain the coolant that is in your radiator by opening the petcock or removing the lower radiator hose. This video shows where the radiator drain plug (petcock) is located on a 2018 GMC Sierra 3500 HD. Fill up the radiator with distilled water and run the engine. Turn off the engine and drain the water, fill up the radiator with antifreeze until you have a 50/50 coolant / distilled water mixture and burp the system.