Autolite Glow Plugs are dependable and long-lasting, providing the perfect plug for a variety of diesel applications. Diesel engines depend on high heat in the combustion chamber to ignite the fuel, and when you cold start a diesel engine, there isn't enough heat to get it going. When you turn the ignition switch, the glow plug warms the combustion chamber to start the fuel ignition. If you're experiencing problems starting your diesel engine, it may have burnt out glow plugs. As America's best-selling glow plugs, Autolite Glow Plugs fit a variety of diesel applications for long-lasting performance and dependability.