How Do I Change the Radiator Fluid in a Chevy Lumina?by John Stevens J.D.
Radiator fluid or “antifreeze” is designed to not only prevent the engine from overheating, but also to prevent the engine from freezing. After repeated heating and cooling over a long period of time, antifreeze looses it ability to protect the engine, and must therefore be periodically replaced. Chevrolet recommends that the Lumina’s radiator fluid by replaced every five years or 100,000 miles, whichever comes first. Changing the Lumina’s radiator fluid is fairly simple, but it is important to properly drain the engine of the old radiator fluid first.
Draining the Radiator
The radiator cannot be properly drained without first alleviating the pressure within the radiator, so the radiator cap must be removed first. At the bottom of the engine-side of the radiator is a drain plug, sometimes referred to as a “petcock.” The plug looks very much like a wing-nut. Grasp the two “wings” with a pair of pliers, then twist the petcock in a counterclockwise direction to remove it. Once removed, the fluid within the radiator will drain out. Note that although the radiator is now drained, there is still a large quantity of fluid within the engine itself and within the heater core, which must be removed. To do so, turn the engine on and allow it to idle, then turn the vehicle’s heater on. As the engine idles, the water pump will pump the fluid from within the engine and the heater core to the radiator, which will drain out of the petcock opening. Finally, it is important to flush the engine with water to remove any debris that has accumulated within the engine’s cooling passageways. Lift the cap located on the top of the radiator’s reservoir, then insert a garden hose into the reservoir. Turn the hose on and monitor the water that exits from the bottom of the radiator. When the fluid exiting from the radiator runs clear, the engine has been flushed. Remove the garden hose and close the cap on the radiator’s reservoir, then reinstall the petcock plug.
Filling the Radiator
The radiator should be filled with antifreeze and water while the engine is running, and the Lumina’s heater is turned on to ensure that the proper fluid level is attained. Only General Motors “DEX-COOL” brand of antifreeze should be used. This brand of antifreeze must be mixed in an equal proportion with water. Pour the mixture into the radiator through the radiator cap until the fluid rests approximately one inch from the cap’s opening. As the engine circulates the fluid throughout the engine, the fluid level in the radiator will drop. Continue to fill the radiator while monitoring the fluid’s level. Once the level has stopped dropping, install the radiator cap and turn the engine off to complete the process.
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