Some vehicles have sealed cooling systems that do not require routine maintenance. Others, on the other hand, should have their water level checked on a regular basis. If the cooling system requires a large amount of water on a regular basis, there is most likely a leak. If the engine is hot, remove the cap with extreme caution. There should be plugs or taps on the side of the cylinder block and the bottom of the radiator for draining the cooling system. Unscrew the retaining clips and slide the two ends apart to remove a radiator hose. If the clips are worn or corroded, they should be replaced.