It does not contain acid and alkali,which does no harm to machine parts and rubber.It will not block the water lane of water tank.It not only can clean the stains,rust,sludge and other dirts in the water tank of general car and engine cooling system efficiently and quickly,but  also can clean the water tank that has not been cleaned for a long  time and with rust serious thoroughly.If the water tank is cleaned by this products,the problems such as the boiling of water tank,overheating of engine can be solved.Aftering using this products,it also can improve the cooling efficiency and engine power,thus saving energy,reducing consumption and prolonging the life expectancy of engine.