Questions and Answers about Plastic Guide Rail Failure in Mercedes

09 Mar, 18

Each year, new models of vehicles come out with the hopes of being better and more advanced than their predecessors. While new models might seem shinier and more impressive on the outside, many of the inner components of the engine are often the same as the previous models—that is, unless the manufacturer discovers a way to improve upon the previous parts and systems of the vehicle. Often this involves utilizing different materials for the various engine parts. Mercedes cars are no exception to this concept in automotive manufacturing.

One of the components that Mercedes has altered in their more recent models is the guide rail. Most drivers aren’t familiar with what a guide rail is or does in a vehicle, so you’re not alone if it doesn’t ring any bells. We’ll talk more about what a guide rail does in your Mercedes’ engine; however, it’s most important to note that Mercedes uses a plastic material for their guide rails, which is prone to failure. Many other vehicles utilize plastic for their guide rails, so escaping the issue is moot. You probably have some questions, so here are answers to the big ones:

Q: What does a your Mercedes’ guide rail do?

A: Also known as a timing chain guide rail, this part is critical in keeping the engine’s timing chain contained to a specific, cyclical motion. The guide rail is responsible for keeping the timing chain “guided” in line and in the correct motion. In more recent years the automotive industry developed guide rails made of plastic materials to improve the performance of the timing chain’s function and lower manufacturing costs. However, there’s always a give and take when utilizing new materials for such critical engine components. For this material, it doesn’t stand up very well to the intense conditions within a hot, sometimes volatile engine environment.

Q: What can cause the guide rail to malfunction?

A: As previously mentioned, the hot temperatures that your engine reaches in your Mercedes pose a challenge for materials that are made of plastic. Your timing chain guide rail is critical for engine functioning, and when it begins to fail it can cause serious engine damage, even total failure. Your timing chain moves at high speeds; when the plastic guide rail begins to break down over time under such hot conditions, it can begin to crack and break, leaving your timing chain susceptible to coming off the rail and snapping or damaging the other parts of your engine.

Q: What are some of the common symptoms of failure?

A: If the guide rail is beginning to come apart, you might notice concerning rattling noises coming from your engine. Any mysterious noises that you experience in your car are usually early warning signs that something’s not right and should be checked out before the problem worsens. Furthermore, debris from pieces breaking off of the guide rail can make their way into your Mercedes’ oil pan. If you’re familiar with how to remove and replace the oil pan, you can take a look yourself to see if it is filled with chunks of guide rail plastic.

Q: Why is it important to enlist the help of a professional?

A: Enlisting the help of a specially trained Mercedes automotive technician is an important step in getting your car the right care. Automotive specialists who are most familiar with the Mercedes brand will be able to detect guide rail issues best, as it is a well known problem area in the vehicle’s design. Furthermore, a professional automotive shop will have the right tools and expertise to properly diagnose and repair the problem in a timely manner.

How we can help

The master technicians here at Santa Barbara Autowerks, located in Santa Barbara, CA, are German-engineering specialists, which includes Mercedes brand vehicles. We know how critical the timing chain guide rail is for the overall function of your vehicle, and when this part begins to deteriorate it can compromise the vehicle’s performance significantly. If you experience symptoms of guide rail failure or would simply like to have a general inspection performed on your Mercedes, please contact us to schedule an appointment as soon as possible. We’ll work together to spare you from expensive repair work in the future.

* Mercedes SL on Asphalt Road image credit goes to: supergenijalac.

* Mercedes-Benz SL 500 image credit goes to: AM-C.