Spark plugs are not the first thing that comes into mind and that is for a specific reason. The spark plugs are not used in diesel vehicles, at least not under the same name. Diesel engines, unlike gasoline engines, do not use spark plugs to induce combustion. Rather, when operating in adverse conditions, they use a different type of plug similar to spark plugs, called glow plugs. Diesel engines make the use of default air temperature to combust the fuel spontaneously and start a burn. This becomes somewhat harder to achieve in colder temperatures since the air temperature is substantially lower than the ignition temperature of the diesel and because of this reason, it becomes more cumbersome to start diesel vehicles. And this is where glow plugs come into play. Pre-chambered engines have these inside the pre-chamber and direct-injected engines, have these glow plugs in the combustion chambers. As the name suggests, glow plug is a metal-based plug with a heating element. This heating element can achieve high temperatures with the help of electric current and use its electrical resistance to heat up the air surrounding it. This heating element can get so hot that it can essentially turn red hot and start radiating light, thus giving it the name “glow plug”. As the temperature of the air inside these chamber start to rise up along with the glow plug, it naturally starts getting close to the ignition or combustion temperature of the fuel, which is diesel in this case. In most of the vehicles, a glow plug indicator shows when to start you vehicle.