Exclusive Car Care Blog

Diesel engines rely on glow plugs to heat the air in the combustion chamber so the engine can start properly, especially in cold weather. Unlike spark plugs in gasoline engines, glow plugs are essential for igniting the fuel-air mixture in a diesel engine when temperatures are low. When glow plugs begin to fail, it can lead to hard starts, misfires, and other performance issues. At Exclusive Car Care, we provide expert glow plug replacement in the greater Phoenix area. Here are five common signs that your diesel glow plugs may be going bad.

Difficulty Starting the Engine

One of the most obvious signs of faulty glow plugs is difficulty starting your engine, particularly on cold mornings. If your engine cranks for a long time before starting or refuses to start altogether, the glow plugs may not be producing enough heat to ignite the fuel. 

Rough Idling After Startup

After your diesel engine starts, it should settle into a smooth idle within a few seconds. If the engine runs rough or sounds like it’s misfiring immediately after startup, it may be due to one or more glow plugs not functioning correctly. Faulty glow plugs can cause uneven combustion in the cylinders, leading to a shaky or unstable idle. 

Increased Exhaust Smoke

Excessive white smoke coming from the exhaust, especially during startup, can be a sign that your glow plugs are not doing their job. When glow plugs fail, fuel may not burn completely in one or more cylinders, leading to unburned diesel exiting through the exhaust. 

Poor Fuel-Efficiency

When your engine has trouble maintaining consistent combustion, it can burn more fuel than necessary. Faulty glow plugs can contribute to inefficient fuel usage. If you notice that your diesel vehicle is using more fuel than usual, it may be due to glow plug issues affecting engine performance and fuel economy.

Check Engine Light or Warning Indicators

Modern diesel vehicles are equipped with sensors that monitor the performance of the glow plug system. If the system detects a malfunction, it may trigger the check engine light or a specific glow plug warning indicator. When this happens, it's important to have your vehicle scanned for diagnostic trouble codes. Ignoring the warning could lead to a no-start situation.

Glow Plug Replacement in Phoenix, AZ

When you need diesel engine repair in Phoenix and the surrounding area, contact Exclusive Car Care at 602-830-4112. Feel free to give us a call to schedule an appointment!