1995 Pontiac Sunfire Owner's Manual - Page 229

To Add Coolant Surge Tank Pressure Cap NOTICE: Your surge tank cap is a psi (124 kPa) 18 pressure-type cap and must be tightly installed to prevent coolant loss and possible engine damage from overheating. When you replace your surge tank pressure cap, a GM cap is recommended. If you need more coolant, add the proper mix at the surge tank, but only when the engineis cool. When replacing the pressure cap, make sure tight. it is Thermostat Engine coolanttemperature 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. 6-24