1989-1991 Chevrolet R3500 5.7L V8 GAS;. 1989-1991 Chevrolet R3500 6.2L V8 DIESEL;. 1989-1991 Chevrolet R3500 7.4L V8 GAS;. Gates - Driven By Possibility. Fuel Tank Cap;. Pre-Release Fuel Tank Cap;. Excess fuel system pressure is relieved through an internal spring and gasket valve that is specially designed to allow venting without losing liquid fuel.
