Reinforced Radiator Expansion Tank Cap for SHACMAN X3000 This reinforced radiator expansion tank cap is built for SHACMAN X3000 and F3000 trucks that work loaded or in dusty mining and construction conditions. It closes the expansion tank firmly and controls system pressure so coolant returns to the cooling circuit instead of escaping. The body is heavier than the standard cap, and the sealing ring and relief spring are sized for constant pressure changes. It is a direct fit