Liqui Moly Pro-Line Radiator Cleaner Deposits in the cooling/heating system create blockages for heat exchange and they also block thermostat valves and control mechanisms. When engine temperatures are too high, the engine runs uneconomically and suffers excessive wear at considerable risk of damage. This concentrate safely removes deposits containing oil and lime and ensures that the engine runs reliably and at the optimum temperature. Does not contain aggressive acids or alkalis.