Using this radiator overflow tank is easy. First, make sure your radiator has a 1 3/16 - inch ID radiator cap as this tank only fits those. Then, simply place the tank under the cap of your radiator. When the coolant in the radiator expands, it will flow into this tank. Remember, this tank doesn't fit New Line Radiators, so double - check your radiator type. For maintenance, check the tank regularly for any cracks or leaks. If you notice any issues, replace the tank right away to keep your radiator system working well.