Compatible & Size: OD 3"/76mm Aluminum alloy fuel cap is used to install the coolant tank with threaded filler neck. Installation: Wipe the water stains and stains next to the water tank with a rag to make the surface smooth and flat; Install the fuel tank cap and adjust the position to the hole position; The junction of the welded fuel tank cap and the fuel tank; Install the fuel tank cap; Check the weld for leaks.