Over time, pockets of air develop within a vehicle's radiator and within the engine's antifreeze passages. When air is present within the system, the radiator's ability to properly cool the engine is impaired. In extreme cases, an air pocket can be large enough to almost completely prevent the antifreeze from flowing through the radiator's hoses. What results is an engine that is subject to overheating. Due to their predominantly horizontal design, General Motors 3.1 liter radiators are particularly susceptible to developing air pockets. Thankfully, bleeding the air out of these radiators is a simple task that should be performed at lease once a year.
Remove the radiator cap. It is located on the passenger's side of the radiator and is black in color. To remove the radiator cap, press down on it while simultaneously twisting it counterclockwise.
Turn the engine on and allow it to reach normal operating temperature. Once the engine is warm, its thermostat will open and allow the antifreeze to circulate through the engine and the radiator. The radiator's antifreeze level will drop once the thermostat opens.
Fill the radiator with antifreeze while allowing the engine to idle, then wait at least five minutes for the antifreeze to circulate throughout the engine. Any air that is present in the system will escape through the radiator cap once it reaches the radiator.
Fill the radiator with antifreeze by pouring it in through the opening that was concealed by the radiator cap. The antifreeze is necessary to fill the void left by the escaped air.
Turn off the engine and allow it to cool.
Install the radiator cap by pressing down on it while simultaneously twisting it clockwise to complete the process.
