Engines {Week 4}

Describe the terms Conduction, Convection, and Radiation, and where would you find them on an car engine?

Conduction: The transfer of heat through a metal. This can be found in the combustion chamber, heat produced by the combustion is transferred to the cylinder walls which are made of metal.

Convection: The transfer of heat through water. E.g. when the heat from the cylinder walls is transferred to the coolant circulating around the engine through the water jackets.

Radiation: The transfer of heat through air. E.g. when the vehicle is being driven, air passes through the radiator which takes the heat away.

What is the purpose of a thermostat?

The purpose of the thermostat is to hold the coolant from flowing around when the engine is cold. When the engine has reached operating temperature, the coolant heats up, and when the coolant reaches the specified temperature required for the thermostat to open. When the thermostat opens, it lets the coolant flow throughout the system.

Why do engines have coolant in them?

Coolant in the engine raises the boiling point of water to prevent it from boiling in normal engine operating temperature.

Coolant is used to prevent the corrosion of valuable internal engine parts. (Precious aluminium head) Water alone in the cooling system would have attacked and corroded the metal. Coolant also acts as a lubricant for the water pump.

When should an oil filter be replaced (miles)?

Around every 6000km – 10000km, different vehicles have different specs.


What projects the oil pressure and where is it situated?
The oil pump projects the pressure. The oil pump is mounted on the engine block behind the crank pulley.