1995 GMC Safari Owner's Manual - Page 232

Radiator PressureCap NOTICE: Your radiator capis 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 the radiator filler neck. Thermostat Engine coolant temperature is controlled by a thermostat inthe engine coolant system. The thermostat stopsthe flow of coolant through the radiator until the coolant reachesa preset temperature. AC@thermostat is recommended. When you replace your thermostat, an