1994 GMC Suburban Owner's Manual - Page 286

Surge Tank Pressure Cap- Diesel Engines NOTICE: Your surge tank pressure cap a unique 15 psi (105 kPa) is pressure-type cap foruse with surge tank cooling systems only. It must be tightly installed to prevent coolant and possible loss engine damage from overheating. sure the arrows on the cap Be line up with the top tubeof the coolant surge tank. Thermostat Engine coolant temperature is controlled by a thermostat in the engine coolant system. The thermostat stops the flow of coolant through the radiator until the coolant reaches a preset temperature. When you replace your thermostat, an AC@thermostat is recommended. Power SteeringFluid NOTICE: Always turn the engine before checking or adding power off steering fluid. The power steering pump cap close tothe fan is and other moving parts. 6-40