2007 Pontiac Grand Prix Owner's Manual - Page 375

You can remove the pressure cap when the cooling system, including the pressure cap and upper radiator hose is no longer hot. Turn the pressure cap slowly counterclockwise. 1. If you hear a hiss, wait for that to stop. A hiss means that there is still some pressure left. 2. Then keep turning the pressure cap to remove the pressure cap. 3. Fill the cooling system with the proper DEX-COOL® coolant mixture, up to the base of the filler neck. See Engine Coolant on page 360 for more information about the proper coolant mixture. 4. Rinse or wipe any spilled coolant from the engine and the compartment. 5. Then fill the coolant recovery tank to the cold fill line. 6. Install the coolant recovery tank cap and the pressure cap. 7. If the coolant in the recovery tank is constantly low, you should have a dealership service department inspect your vehicle for leaks. {CAUTION: You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts are hot enough. Do not spill coolant on a hot engine. 375