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. Secure your purchase: Glow Plug (MPN 20915963) includes a 12-month warranty!

About SWAG

SWAG specializes in precision-engineered replacement parts for steering, suspension, and engine components, ensuring reliability and long service life.

Why Choose SWAG?

• SWAG parts are made to the same high standards as original equipment, so you get reliable performance. • We offer a wide range of parts for many different car makes and models – we likely have what you need. • SWAG parts are a smart value – quality you can trust without breaking the bank. • Our parts are thoroughly tested to make sure they’ll last, giving you peace of mind on the road. SWAG – trusted quality, available at FixParts Online!