The camshaft is linked to the crankshaft through a timing belt and regulates the opening and closing of the intake and exhaust valves in each cylinder in time with the motion of the piston. An engine designated OverHead Camshaft (OHC) locates the camshaft in the cylinder head. An engine with Double OverHead Camshaft (DOHC) has two camshafts, one to regulate the intake valves and one to regulate the exhaust valves.

The purpose of an automobile engine's cooling system is to circulate coolant around the engine so it can absorb and dissipate heat. The water pump pumps coolant through the various components in the system and the radiator cools down coolant after it has heated up after passing through the engine. The thermostat controls the flow of coolant based on engine temperature while the cooling fan draws air through the radiator when the car isn't moving fast enough for unforced air to cool things down on its own.

The battery supplies the power necessary to start the engine when the ignition switch is is turned on.

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.

The master (brake) cylinder converts pressure on the brake pedal to hydraulic pressure in the brake lines.