The radiator is probably the most vital element of the cooling system in the Pontiac Bonneville. In order to keep it working at peak efficiency, an owner must perform regularly scheduled maintenance. Flushing the radiator is a prime example of this maintenance. This task doesn't require any specific automotive training, just follow these easy directions.
Move the Pontiac Bonneville to a flat area and engage the parking brake. Then, open the hood and verify the external temperature of the radiator. If it's warm to the touch, wait for it to cool.
Turn the radiator cap one full rotation, step back and wait a few seconds, and then remove the cap completely. Any time you open a radiator, you need to be very cautious, as it can spew hot coolant and burn anyone in the area.
Position a 2-gallon bucket underneath the radiator and below the drain plug. In some year models of the Pontiac Bonneville, there may be no drain plug. In this case, you will need to remove the upper and lower radiator hoses and conduct the flush through them. Before you remove the hose, squeeze it. If the hose is tight, that means there is coolant in the hose and you need to be very careful.
Remove the drain plug or radiator hose and allow the old coolant to drain completely from the car. When it finishes, be sure to pour the coolant into a sealable container and put the bucket back into its original position.
Close the drain hose or plug. Fill the radiator with distilled water to begin the flush. Next, open the plug or hose to allow the radiator to drain into the bucket. Replicate this procedure until the water runs debris free out the bottom of the radiator.
Replace the Pontiac Bonneville's drain plug or radiator hose and dispose of the coolant flush.
Refill the radiator with fresh coolant to within an inch of it overflowing. Check the drain plug and hoses for any possible coolant leaks.
Start the Pontiac Bonneville and turn the heater to high. Allow it to run for about 10 minutes or until the cooling fan turns on twice, whichever comes first. Then, switch the engine off and check the coolant level. If it is lower, then add more coolant. If not, put the radiator cap on and close the hood.
