1997 Buick Riviera Owner's Manual - Page 262

Radiator Pressure Cap Power Steering Fluid I NOTICE: Your radiator cap isa 15 psi (105 kPa) pressure-type cap and must tightly installed to be prevent coolant loss and possible engine damage from overheating. Be sure the arrows on the cap line up with the overflow tubethe radiator on filler neck. When you replace your radiator pressure a GM cap cap, is recommended. Thermostat Engine coolant temperature controlled by a thermostat is in the engine coolant system. thermostat stopsthe The flow of coolant through the radiator until coolant the reaches a preset temperature. When you replace your thermostat,GM thermostat a is recommended. 6-25