Glow plugs (also known as glowplugs or glow-plugs) are used in diesel engines. Particularly in colder weather, the glow plug is the heating device used to ignite the diesel. These components can be likened to small electric heaters. Diesel engines operate differently to petrol engines as diesel has different combustion properties. Diesel needs to be heated more than petrol before it ignites, thus glow plugs are used in diesel engines. Direct injection motors have the glow plugs situated in the combustion chamber.
These are pencil-shaped metallic objects that have a heating element at the tip. When electricity passes through this component it begins to heat up and, when hot enough, the component ignites the diesel that comes into contact with it. If these plugs are not working properly and the diesel engine is not starting, it might be necessary to have these components replaced. Glow plugs are to diesel engines what spark plugs are to petrol engines. Monitor the starting of your diesel engine and, if you find it hard to start, there might be a problem with the glow plugs in the vehicle.
Always remember to quote the make and year model of your vehicle when purchasing these components. This will ensure that the correct plugs are supplied. In older diesel vehicles, if the ignition was turned to the on position the driver would need to wait for the glow plug light to come on before the engine would start. This ensured that the engine and glow plugs were sufficiently heated, and that it was safe to start the vehicle. If the ambient temperature of the vehicle is hot enough, the engine can be started without any delay.