1996 Buick Roadmaster Owner's Manual - Page 206

I plain water or the wrong mix,your engine could get toohot but you wouldn't getthe overheat warning. Your engine could catch and you or fire others could beburned. Use a 50/50 mix of clean water and DEX-COOL antifreeze. 1. You can remove the coolant surge tank pressure cap when the cooling system, including the coolant cap - surge tank pressure and upper radiator hose, is no longer hot. I NOTICE: In cold weather,water can freezeand crack the engine, radiator, heater core and other parts. So use the recommended coolant. Turn the pressure cap slowly about one-quarter turn to the left and then stop. If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left. You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts arehot enough. Don't spill coolant onhot engine. a 5-16 -