1996 GMC Jimmy Owner's Manual - Page 272

Radiator Pressure Cap NOTICE: Your radiator cap isa 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 arrowson the cap line up with the overflow tube on the radiator filler neck. Thermostat Engine coolant temperature is controlled by a thermostat in the engine coolant system. Thethermostat stops the flow of coolant through the radiator until the coolant reaches a preset temperature. 6-25