Your Mercedes has a serpentine belt that powers many other components in the car but requires something known as a belt tensioner to stay tight and rotate efficiently. The belt tensioner is an important component that, when faulty, can lead to the failure of several components in the engine. Let’s go a little further into detail about what the belt tensioner is and how one can replace it so that your Mercedes remains in its best shape.
What is a Belt Tensioner?
The belt tensioner is a small but essential part of your car’s engine. It maintains the proper tension on the serpentine belt, which drives multiple engine accessories like the alternator, power steering pump, and air conditioning compressor. The tensioner ensures the belt stays tight and runs smoothly around the pulleys. Without it, the belt could slip off or wear out quickly, leading to a host of issues.
Replacing the Belt Tensioner
- Locate the Belt Tensioner: Pull the hood of your Mercedes to get to the belt tensioner. It is often positioned close to the serpentine belt. This belt goes around several pulleys and the tensioner is responsible for maintaining tightness on the belt. If you are confused as to where it is, your owner’s manual should have a picture showing you the position.
- Release the Tension: In order to take the serpentine belt off, it is necessary to loosen it up first. You can do it with a wrench or a special belt tensioner tool that is designed for turning the pulley. Rotating this pulley will help you adjust this belt to a position where you can easily remove it from the pulleys. Care must be taken at this time because the tensioner is spring loaded and may reverse its direction unexpectedly, so it is advisable to have a good grip on the tool.
- Remove the Old Belt: After that, the tension will be released slowly and then the serpentine belt can be removed from the pulleys. Look at the direction in which the belt is trained around these different pulleys, or check for a belt training diagram if provided. This will assist you to correctly fix the new belt. It is also important to mark the path of the belt so that no mistakes are made during the reapplication process.
- Remove the Old Tensioner: Next, you have to unscrew the bolts using a wrench or a socket set to be able to free the tensioner. When the bolts are pulled off, you should remove the old tensioner from the engine assembly. Do not allow any of the bolts to fall within the engine compartment as they may be hard to retrieve.
- Install the New Tensioner: Mount the new tensioner where the previous one was removed. Bolt it, making sure it is properly positioned and screwed tightly. The tensioner should also be properly oriented so that the belt remains tight and the tensioner works effectively.
- Reinstall the Belt: Route the serpentine belt around the pulleys following the right path as when you were taking it out. Using the tensioner tool, twist the tensioner pulley in the other direction until the belt fits in.
Let A Professional Do The Job
As simple as these steps sound, you should not try them because there’s a lot that can go wrong if you are not a trained mechanic. When you are ready to replace the belt tensioner, let it be done by a certified mechanic to avoid more costly issues.
Visit The Trusted Mercedes Experts In San Rafael
When it comes to giving proper attention to 
European vehicles in San Rafael, CA, and the surrounding area, there is only one place to turn: Heynneman European. We have a highly qualified team of mechanics and our garage has been in business since 1979, making us fully equipped to either repair or service your Mercedes.
The belt tensioner on a Mercedes is a very important component of the vehicle’s engine, so if you find that this part is not working properly, then you should bring your Mercedes to us for the right replacement. Our expert service also includes drivers from Larkspur, Kentfield, Corte Madera, Mill Valley, San Anselmo, and Fairfax CA. Schedule your next Mercedes maintenance by contacting us through the phone number 415-499-1234.
