While petrol or gasoline engines have spark plugs, diesel engines use something else to ignite fuel for startup: the glow plug. Whatever type of engine your car's fitted with, it requires a certain amount of heat in order to even start. In a gasoline engine, this heat comes from the spark plugs that directly connect to the cylinders. So whether your engine is cold or hot, there won't be any problems starting a petrol-powered car (unless a cold engine means it's iced). In diesel-powered cars however, even a regularly cold engine is a hassle.
Enter the car glow plug. See, instead of relying on an electrical spark to ignite the air-fuel mixture in the cylinders like in a gasoline engine, diesel engines use a different method. Specifically, the diesel engine compresses air, raising its temperature to a certain point. It is when that point is reached that fuel is sprayed inside the engine cylinders, creating explosions for power. The plug's job is to pre-heat the diesel engine, aiding it in beginning and sustaining its own internal combustion process. That's why you can't immediately start a diesel engine, especially if it's cold. Once you insert the key and partially turn it to the "on" position, you have to wait for the "wait-to-start" light to go out before turning the key all the way. This gives the plug ample time to preheat the engine for startup. And of course, if a diesel engine's seen some fairly recent use, or if the ambient temperature is pretty hot, the use of the glow plug won't be necessary at all.
What does the car glow plug look like exactly? It's a piece of metal that's shaped like a pencil, with a heating element on one tip. Once exposed to electricity by way of the glow plug relay, the tip begins to emit light and heat, preparing the diesel engine for startup. For optimum operation, these tips are usually crafted from elements like platinum and iridium, both of which are resistant to oxidation and are able to sustain extreme temperatures.
But it's not as simple as that. Way higher temperatures than necessary can actually damage some glow plugs. As with other things that use electricity, too much heat can burn them out. To prevent this from happening, we advise that you turn this component off after the engine has started operating. Additionally, these plugs also have a short life span. As they get older, they become less efficient, making it more difficult to start your engine. This problem becomes even more evident during the winter, when you realize that your glow plugs have seen better days. Once this happens, don't hesitate to look for a replacement immediately.
Here at Parts Train, we can sell you a high-quality, durable glow plug at the lowest price online. Remember: fuel efficiency depends on the quality of your car's components, so make sure you fit your car with only the best parts on the market.