Water Pump and Car Coolant System
Almost all cars have a water pump that circulates coolant around the engine, through the radiator and into the cars heater system. In most cases your cars water pump is driven via the Cam Belt or Timing Belt from a crankshaft pulley at the front of the engine. When the Cam Belt or Timing Belt is changed, as routine maintenance, this is the perfect time to check for excessive play or damage to the cars water pump or gaskets as to change it during a Cam Belt or Timing Belt replacement is a more simple and cost effective process than doing only the water pump.
Anti-Freeze and Coolant Additives
Modern car coolant systems use less and less liquid as anti-freeze and coolant additives improve, these improvements also mean that the corrosion to the engine caused by the constant heating, cooling and being submerged in water is greatly reduced. Coolant additives are commonly know as Anti-Freeze which traditionally stopped the cooling system from freezing in the winter. Modern additives now offer improved cooling in hot weather as well.
The radiator is place at the front of the car and is connected to the engine with rubber hoses, this allows the hot coolant to leave the engine an enter the top of the radiator, from here it travels down through the fins of the radiator and gets pumped back into the engine at the bottom, therefore completing the cooling circuit. As the coolant travels through the fins of the radiator the air coming through the front grill of the car cools coolant so it's ready to re-enter the engine at a lower temperature.
A thermostat is used to keep the engine at the optimal running temperature. This is temperature controlled valve that opens and shuts as required to let more or less coolant through the engine. An engine that runs at the its optimal temperature will give better performance and fuel economy.
Car Heater System
Part of the car coolant is diverted through the cars heater system, also known as the heater matrix, where it uses a method very similar to the cars radiator to heat the car. The coolant is pumped through a smaller radiator and your heater fan blows air across this and into the cabin through directional vents. By using the heater controls on the dashboard more or less air is diverted through the heater matrix to control the temperature coming through the vents.