The function of the cooling system in your vehicle is to remove excess heat from the engine. One third of the heat generated from combustion of fuel is dissipated through the cooling system. The water pump circulates the coolant through the passages of the engine to capture waste heat from internal combustion. Neglecting cooling system maintenance can lead to system failure. Cooling system problems are the number on cause of mechanical breakdown in the U.S. Scale and deposits on the walls of the cooling system passages can reduce the transfer of engine heat to the coolant, resulting in overheating.