Removing the air from your engine's cooling system, or “burping,” is crucial when it comes to extending the life and reliability of your automobile. Burping needs to be done after any change to the cooling system such as draining or filling it. Failure to do so can result in trapped pockets of air in the cooling system. These lead to hot spots, or localized overheating, which can crack engine components.
Check your work. Before you burp your radiator, make sure that you have correctly completed any and all work on the cooling system. If not, you will be destined to repeat this procedure at some point in the future. Some GM cars have aluminum engine components. If your car does, then make sure that you used the specialized coolant manufactured specifically for GM engines with aluminum parts. Make sure any leaks are repaired, otherwise air will slowly leak back into the system and cause problems.
Allow your engine to cool completely to ambient temperature. In your clean plastic container mix your coolant with distilled water in a 1-1 ratio. Cover your radiator cap (not to be confused with the coolant reservoir) with a rag and take off the radiator cap. Using the funnel, pour your coolant/water mixture into the radiator until it is filled to the very top. Fill your coolant reservoir with the same mixture, again using the funnel, until you reach the “full” mark on the reservoir. Remove the funnel and put the cap back on the reservoir but leave the radiator cap off.
Start your car. It should be in park, or neutral if it's a manual transmission, with the parking brake on. Do not rev the engine unnecessarily.
Get out of the car and shine the flashlight on the opening to the radiator. As your car warms up the thermostat will open and allow the circulation of the coolant mixture throughout the entire cooling system. As it is pumped, the coolant will carry any air bubbles in the system back to the radiator where they will bubble up and leave the radiator through its open cap. The coolant level will drop inside the radiator as this happens. Keep filling the radiator with the coolant mixture to ensure that it is always topped off.
Shut off the engine when the “burping” stops and the coolant is topped off. Replace the radiator cap, fill your coolant reservoir to the line and you are done.
