1993 Buick Riviera Owner's Manual - Page 235

A CAUTION: Turning the radiator pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn youbadly. With the coolant recovery tank, you will almost never haveto add coolant at the radiator. Never turn the radiator pressure cap even alittle -when the engine and radiator are hot. Radiator Pressure Cap -- Add coolant mixat the recovery tank, but be careful not When you replace your radiator pressure cap, ACS an to spill it. cap is recommended. A CAUTION: You can be burned if you spillcoolant on hot engine parts. Coolant contains ethylene glycol, and it will burn ifthe engine parts are hot enough. Don't spill coolant on a hot engine. Thermostat I Engine coolant temperature controlled by a thermostat is in the engine coolant system. The thermostat stops ,the flow of coolant through the radiator until coolant the reaches a preset temperature. When you replace your thermostat, an AC@ thermostat is recommended. 233