1. There are different kinds of fuel systems, but they all have a way of mixing air and fuel into a vapor, which will explode and burn in the engine.

2. The ignition system takes current from the battery, strengthens it, and feeds it through the distributor to the spark plugs in regular order. The spark plugs make the current into hot sparks, which ignite the mixture of fuel and air.

3. The lubricating system pumps oil to all the moving parts of the engine so they will move smoothly and not get too hot. But even with the oil, the engine builds up a great deal of heat.

4. The cooling system moves heat out of the engine into the air around the car. If the engine is cooled by a liquid, the cooling system moves the liquid through the engine and out of the car's radiator, where a fan blows air past the radiator to cool off the liquid.