Most people aren’t familiar with what glow plugs are or how they work, but if you drive a diesel-engine Mercedes, it’s an important part of your engine. When it’s cold outside and you turn the key to start your car, your engine may struggle to turn over and fire up. Diesel engines, in particular, may have a hard time because the cylinder block and head absorb much of the compression heat needed for ignition.

Glow plugs, which resemble pencil-shaped pieces of metal, are responsible for quickly heating up the engine. The “glow” in the plug happens when the heating element at the tip of the plug becomes electrified if the engine isn’t warm enough for combustion, which accelerates the fuel ignition process.

Over time, the glow plug relay can wear out and eventually fail on you. As we approach times of colder weather, you may notice that your car is not running as well as it normally does. If you suspect that the glow plug relay may be at fault, read on to learn how to troubleshoot the problem and to take the steps necessary to make sure your Mercedes is properly maintained.

Most Common Cause of Glow Plug Relay Failure

Like most other car parts, the glow plug relay can wear out naturally over time. Exposure to extreme temperatures as well as fluctuating electrical currents and misfiring injectors can also play a part in accelerating the process.

You can maximize the life out of your Mercedes by keeping up with all routine maintenance and having it serviced quickly if you notice any performance changes.

What Are Warning Signs of a Glow Plug or Relay Failure?

These are a few common indicators that you are experiencing a glow plug or relay failure:

• Dashboard warning: The glow plug dashboard light may flash or the check engine light could come on when you try to start your car if there is a problem with your glow plugs. When you start your car during colder-than-normal weather, you’re probably used to seeing the glow plug dashboard light come on for a few seconds while it warms up your engine. If the light doesn’t come on or it begins flashing, it’s the first warning sign that something may be wrong.
• Difficulty starting your car. If your car takes longer to turn over than normal on a cold morning, this could also be a warning sign.
• The presence of white smoke until the engine warms. This could be a sign of injection timing or injection pump issues, both of which would impact glow plugs and the relay. It is likely not a coincidence if the white smoke clears out as soon as your car is warmed up. This white smoke is not to be confused with normal condensation.
• Rough idling or hesitation after your car has started. This is also a sign that there could be a glow plug, relay, or injector issue.

If you experience any of the issues above, you’ll need to service your Mercedes as soon as possible. If your car is exhibiting minor issues, you will still want to diagnose the problem as soon as you can. With most automotive issues, small issues can quickly turn into larger issues or complete engine failure if left uninspected for a long period of time.

Fixing Your Mercedes Glow Plugs or Relay

No one likes to hear that their car needs to be serviced, but in most cases, glow plug and relay problems can be easily identified and repaired. It is still strongly encouraged that you seek out the assistance of experienced technicians. Injectors, glow plugs, and relays all need to work together in harmony for your car to run efficiently. You will want to make sure the problem is examined by someone who can accurately diagnose the issue and quickly get your car back on the road.

Das European Autohaus are the Experts You Need

When you experience issues with your glow plugs or relay and are ready to have your Mercedes serviced, Das European Autohaus is happy to assist! Specializing in European auto repair, we have been serving the Spring and Houston, TX area for decades as your reliable and affordable alternative to dealerships. Let us get you back on the road today! Give us a call to set up an appointment.