1996 Buick LeSabre Owner's Manual - Page 251

Radiator Pressure Cap Power Steering Fluid NOTICE: Your radiator cap is a 15 psi (105 kPa) pressure-type cap and must be tightly installed to prevent coolant loss and possible engine damage from overheating. Be sure the arrows on the cap line up with the overflow tube on theradiator filler neck. When you replace your radiator pressure cap, an AC? cap is recommended. Thermostat Engine coolant temperatureis controlled by a thermostat in the engine coolantsystem. The thermostat stops the flow of coolant through the radiator until the coolant reaches apreset temperature. 6-23