Signs of Plastic Guide Rail Failure in Mercedes

Mercedes cars have been at the forefront of engineering and technical innovation for many years. With superior parts and carefully-considered designs, a well-cared for Mercedes is guaranteed to give you the drive of your life.

However, with time and age, even the best cars may show signs of wear and tear, and it is always important to be aware of these issues. In this article, we will take a closer look at your Mercedes plastic guide rail, exploring how you can prevent failure and how you can tell if failure has already occured.

What is a guide rail?

A guide rail is a relatively new addition to motoring that a handful of newer models of vehicle have installed. However, unlike other vehicles, the guide rail in a Mercedes is made of strong, reinforced plastic.

The guide rail’s purpose in your Mercedes is to work alongside the engine’s timing chain, helping it to circulate properly and stay in line with the other systems connected to the engine. The guide rail is paramount for keeping the timing chain aligned. It prevents it from slipping or deviating from its position, similar to a how a splint works for a broken finger.

What can cause a guide rail to break?

There are several factors which could cause your guide rail to break. Being aware of them can really help avoid some catastrophic damage down the line. Read below for some of these signs.


The most common cause of guide rail breakage is excess heat within the engine. High heat can warp and melt plastics, which is exactly what your Mercedes guide rail is made of. Issues with your engine overheating or driving in extreme temperatures can put undue stress or strain on the guide rail. Therefore, if you’ve had issues involving your car and heat, it’s probably wise to check on the guide rail’s condition.

High Speeds

Consistently driving at top speed or very high speeds can also cause your guide rail to fail. Excess speeds can cause your engine to run too hot for too long, once again exposing your guide rail to the risk of melting. If it does melt, then it can lock up the timing belt entirely. It can also fuse to other parts within the engine, causing all manner of problems and costly repairs.

Impacts and Bumps

If you’ve had a minor impact, either with a curb or a another vehicle, or if you have been driving on very rocky or rugged terrain, it is always best to check on the state of the guide rail. Regular bumps and knocks can put strain on plastic, weakening it and even causing it to suddenly shatter.

Age and Maintenance

As with all things, time can naturally lead parts to become worn or weak. Combined with poor maintenance and bad driving habits, the parts in your Mercedes can become worn out much faster.

How to Tell if the Guide Rail is Broken

As with many problems and failures, your car will often tell you if something is wrong. In the case of a plastic guide rail failure, you are likely to hear shaking or vibrating sounds from under the hood when driving. This is because the rail has become warped or loose and is able to move freely and excessively.

If this is left unchecked, your Mercedes will still give you one final warning. When pieces start to break off, they will begin to appear in your vehicle’s oil pan. These loose parts can cause severe engine damage by contaminating your car’s oil as well as potentially blocking the systems that circulate with engine oil.

If blockage doesn’t ruin your Mercedes engine first, then the complete failure of the guide rail will. If it finally shatters, the main shards will impact all the parts around it. It is likely that smaller parts will get drawn into the engine’s internal systems, causing a very expensive repair bill for multiple parts of your engine.

Seek Repairs from a Trusted Shop

When your Mercedes guide rail begins to fail, your only option is to seek immediate repair. While you may find professional repairs expensive, replacing a guide rail really costs nothing compared to the cost of an entire engine replacement.

Luckily, if you are a Mercedes driver in the Winter Park or Orlando area of Florida, then the trusted mechanics at Green Garage will be happy to serve you. With a three-year warranty on all work performed here, you can drive away knowing all work is guaranteed.