Common Myths About Glow Plugs
Glow Plugs vs Spark Plugs
Glow plugs and spark plugs perform the same function of igniting the engine, but they also serve different purposes. In addition to appearance, there are other important differences between the two types of candles.
1. Fuel: Spark plugs work in gasoline engines, while glow plugs are used in diesel engines. In gas engines, the spark plug creates a spark that ignites the air-gasoline mixture in the combustion chamber. Glow plugs have the same function but are used in diesel engines.
2. Heat difference: Gasoline is very volatile so all it needs is a spark to release the vapor. Diesel is less volatile and diesel engines have more intense cylinder compression so it needs more heat to ignite. Only glow plugs can generate this amount of heat to ignite the air-diesel mixture in the combustion chamber of a diesel engine.
3. Durability: Glow plugs last longer than spark plugs. This is because spark plugs work continuously while the car is running. Glow plugs, on the other hand, only work during the ignition process.
4. Ignition Process: Spark plugs use electrical energy to create a spark to ignite the mixture in your engine.
Over time, glow plugs wear out, affecting your vehicle’s performance. Your vehicle may still start and be driven, but it will not be as efficient as with undamaged glow plugs.
When glow plugs become weak, it may take several starts and you may need to press the accelerator pedal to reach higher speeds. If you live in a cold climate, your vehicle may not start at all because the glow plugs cannot generate enough heat to cause combustion.
Aside from the inconvenience of having to drive at a reduced speed and repeatedly trying to ignite the engine, faulty glow plugs will affect your vehicle’s fuel efficiency. They will also increase your vehicle’s carbon dioxide emissions.
Common Misconceptions About Glow Plugs
Unfortunately, there are a few common misconceptions that can lead to confusion and improper maintenance. These misconceptions can lead diesel vehicle owners to make incorrect assumptions about how glow plugs work:
Myth 1) Glow plugs need to be replaced every time your vehicle is serviced.
That’s simply not true. While regular maintenance is important to the overall health of a diesel engine, glow plugs do not need to be replaced at every service interval. Glow plugs are designed to last longer than spark plugs, typically lasting 60,000 to 100,000 miles depending on the vehicle and driving conditions.
Myth 2) Glow plugs are only important in cold seasons. Of course, glow plugs are essential for starting a diesel engine in cold temperatures, but they’re not just for winter.
Myth 3) Defective glow plugs will prevent the engine from starting.
Faulty glow plugs can make the engine difficult to start, especially in cold weather, but they won’t necessarily prevent the engine from starting. A diesel engine may start with one or more faulty glow plugs, but it will experience reduced performance, increased emissions, and a higher chance of misfires.
Myth 4) Glow plugs are only found on older diesel engines.
Some people believe that modern diesel engines like Duramax, Cummins, and Powerstroke don’t use glow plugs, but that’s simply not true. Newer diesel engines have advanced technology like common rail high pressure injection and piezoelectric injectors, but they still rely on glow plugs to initiate and ensure optimal combustion.
Myth 5) Glow plugs and spark plugs are interchangeable.
Among many other myths, this is actually dangerous. Glow plugs and spark plugs are designed for completely different types of engines and serve different purposes.
