Fan spacers position fan closer to radiator or fan shroud and away from pulleys. 1-1/2" and larger spacers are uniquely designed allowing spacer to remain bolted to water pump while changing fans. Aluminum spacers include 3/4" to 5/8" water pump shaft reducer bushing, four allen bolts to secure spacer to water pump, and four hex bolts with washers to secure fan to spacer. Spacers work with 1-3/4" bolt circle flanges only