1998 Cadillac Catera Owner's Manual - Page 272

Adding Coolant If you needmore coolant, add theproper Dm-COOL@ coolant mixture at the surge tank, but only whenthe engine is cool. Surge Tank Pressure Cap NOTICE: The surge tank cap is a 15 psi (105 kPa) pressure-type cap and must be tightly installed to prevent coolant lossand possible engine damage from overheating. If the surge tank pressure needs tobe replaced, a cap GM cap is recommended. 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. Don't spill coolant a hot engine. on When replacing the pressure make sureit is tight. cap, Thermostat Engine coolant temperature is controlledby a thermostat in the engine coolant system.The thermostat stops the flow of coolant through the radiator until the coolant reaches a preset temperature. If the thermostat needs to replaced, aGM thermostat be is recommended.