G 2500 3/4 Ton Van V8-6.5L DSL Turbo VIN F (1997)
Radiator Cap: Description and Operation
WARNING: As long as there in pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the
solution in the radiator, without causing the solution to boil. Removal of the radiator cap while the engine is hot and the pressure is high will
cause the solution to boil instantaneously and possibly with explosive force, spewing the solution over the engine, fenders, and person removing
the cap. Under some conditions, the engine coolant is combustible.
Operation
A pressure-vent cap is used with the cross-flow radiator to allow a buildup of 103 kPa (15 psi) in the cooling system. This pressure raises the boiling
point of coolant to approximately 125°C (262°F) at sea level. DO NOT remove radiator cap to check engine coolant level; check coolant visually at
the see-through coolant reservoir. Coolant should be added ONLY to the reservoir, when the system cools.
The pressure-vent radiator filler cap contains a blow off or pressure valve and a vacuum or atmospheric valve. The pressure valve is held against its
seat by a spring of predetermined strength, which protects the radiator by relieving pressure if it exceeds design limits. The vacuum valve is held
against its seat by a spring, which permits opening of the valve to relieve vacuum created in the system when it cools off and which otherwise might
cause the radiator to collapse.
Design
The radiator cap is designed to discourage inadvertent removal. A rubber asbestos gasket is added to the diaphragm spring at the top of the cap.
Embossed on the cap is a Warning against its being opened and arrows indicating the proper closed position.
