1997 Pontiac Sunfire Owner's Manual - Page 271

Adding Coolant Surge Tank Pressure Cap If you need more coolant, add the proper DEX-COOL' coolant mixture at the surge tank, but only when the engine is cool. 1 NOTICE: Your surge tank cap a 15 psi (105 kPa) is pressure-type cap and must be tightly installed to prevent coolant loss and possible enginedamage from overheating. When you replace your surge tank pressure cap, a GM cap is recommended. You can be burned you spill coolant on hot if engine parts. Coolant contains ethylene glycol, and it will burn if the engineparts are hot enough. Don't spill coolanton a hot engine. 1 1 When replacing the pressure cap, make sure it is tight. Thermostat Engine coolant temperature is controlled by a thermostat in the engine coolant system. The thermostat stops the flow of coolant through the radiator until the coolant reaches a preset temperature. When you replace your thermostat, an AC@thermostat is recommended. 6-27