How Much Antifreeze/Coolant Does A 2002 Pontiac Bonneville Take?

A guess would be about 2 gallons (1 gallon of anti freeze split 50/50 with water). Use this as a starting point and not an exact measurement. After your flush and you are about to refill, put in about 1 gal of the mixture and start the car leaving the radiator cap off. Open the heater control and check that the thermostat has opened by viewing the flow through the radiator cap opening. When the engine warms up pour in additional coolant to top off the radiator, replace the radiator cap and put enough coolant into the overflow tank to bring the level to the cold fill line. Allow the engine to run for another 5 minutes or so until it reaches normal operating temp and then shut it off. Wait and it will draw coolant back into the radiator from the overflow tank. When cool, check the level in the tank and add more antifreeze to bring it to the "full cold" line. Good luck and remember to properly dispose of the old coolant.