These little guys are basically tiny electric heaters inside your engine. They heat up the combustion chamber—the space where the fuel and air mix—to get things started, especially when it’s cold. They’re a resistive heater, meaning electricity flows through them and creates heat. It’s a pretty simple idea, but crucial. They're most important in diesel engines. Diesels don’t have a spark plug like a gas engine. Instead, the extreme heat from the glow plug ignites the fuel. When you turn the key, the glow plugs preheat that air, and that makes it possible for the diesel fuel to ignite on compression. They usually only run for a short time when starting, and sometimes briefly after, depending on the engine and the temperature. After the engine is warm, they typically aren’t needed. If a glow plug goes bad, your engine will be really hard to start, especially in cold weather. It might start eventually, but it’ll be struggling. You’ll notice if it's taking a long time to fire up, or if it's running really rough when it does. They act like a shield against cold starting issues. If multiple plugs fail, it may not start at all. They’re relatively inexpensive parts, and replacing them proactively can save you a lot of headaches down the road. We often see folks get a set of them replaced together, since they tend to wear out around the same time. You can find glow plugs and a lot of other engine parts at places like Fixparts Online, but we keep a good stock here too. A warranty you can count on: Glow Plug (MPN DG004) has a 12-month guarantee!

About DENSO

Denso is a leading global supplier of automotive components, providing advanced systems for thermal, powertrain, and electrification.

Why Choose DENSO?

• DENSO parts are known for lasting a long time, so you won’t have to replace them as often. • They’re made with high-quality materials and tested thoroughly, meaning they perform reliably. • DENSO offers a wide range of parts, covering many different makes and models of vehicles. • As an original equipment supplier to many car companies, you’re getting the same quality parts the vehicle came with. FixParts Online – Your Trusted Source for Quality DENSO Auto Parts.