The cooling system consists of a radiator, expansion tank, viscous drive fan, thermostat, and mechanical water pump. Small block and certain special-performance large block Corvettes use an aluminum cross-flow radiator. Most large block Corvettes utilize a larger capacity radiator of conventional copper-brass alloy. The viscous drive fan restricts operation at 1,500 rpm in cold weather and 3,500 rpm during warmer temperatures. This fan requires less horsepower to drive during high rpm operation and reduces under-hood noise.
Corvettes equipped with aluminum radiators demand certain precautions during normal operation and maintenance. Caution is advised when removing and replacing the filler cap, to avoid denting or scratching the sealing surfaces of the filler neck. Do not use replacement filler caps that use brass in their construction. Extended use will damage the radiator and necessitate extensive repair or replacement. The same precautionary measure should be taken with replacement drain cocks. A 1 / 8 in. cast iron plug may be substituted only for an extremely short period of time. Use only antifreezes and cleaners that are recommended for aluminum cooling systems.