replacing mercedes-benz timing chain pulley

Mercedes-Benz Timing Chain Tensioner Replacement

Is your Mercedes-Benz engine misfiring, noisy idling, and the check engine light is on due to a faulty timing chain tensioner? Learn how to fix the problem by replacing the timing chain tensioner of your Mercedes-Benz.

This guide provides instructions on replacing the timing chain tensioner on a Mercedes-Benz E, C, S, CLS, ML, GL, and R Class from 2006 to 2012 equipped with the V6 and V8 gasoline M272 and M273 engines.


Common symptoms of a bad timing chain tensioner include:

  • Rattling noise at startup
  • Check engine light on
  • Engine misfire
  • Engine noise at idle

What you will need

Bestseller No. 1
Bapmic 2710500911 Engine Timing Chain Tensioner for Mercedes Benz W204 R172 C250 SLK250 2012-2015
Bapmic 2710500911 Engine Timing Chain Tensioner for Mercedes Benz W204 R172 C250 SLK250 2012-2015
For Mercedes C250 SLK250 2012 2013 2014 2015; Replacement OEM ( Original Equipment Part) Number: 2710500911, 271 050 09 11


  • Mercedes-Benz Timing Chain Tensioner



  1. Park the vehicle on level ground and set the parking brakes.
  2. Allow the engine to cool down.
  3. Pull the hood release under the dashboard and open the hood.
  4. Disconnect the battery negative terminal. The battery will be in the trunk, passenger seat, or engine bay, depending on the model.
  5. Create a simple drawing of the route of the serpentine belt.
  6. Use a 27mm socket and ratchet to turn the crankshaft clockwise. Set the crankshaft at forty degrees. Turn the crankshaft clockwise only.  Crankshaft degrees are stamped on the inner side of the crankshaft pulley. Remove drive belt mercedes m272 to change tensioner
  7. Use a 17mm socket and ratchet to loosen the serpentine belt tensioner. serpentinebelttensioner
  8. Remove the serpentine belt.
  9. Use the E12 socket to remove the four bolts that secure the alternator. alternator
  10. Remove the ground, positive and main connector from the alternator.
  11. Move the alternator out of the way. You can lower the alternator. It should give you enough room to access the timing chain tensioner. If you prefer, remove the alternator from the engine bay.
  12. Place an oil pan directly below the chain tensioner to catch the oil.
  13. Remove the timing chain tensioner using a 19mm socket.timing tensioner
  14. Install the new timing chain tensioner. Using a torque wrench, torque the tensioner bolt to specs. Typically 80 Nm. Verify by calling your Mercedes-Benz dealer.
  15. Reconnect alternator wires. Reinstall alternator bolts.
  16. Remove the rubber cap (behind the last ignition coil, driver side) at the back of the engine and insert a T60 wrench.
  17. Extend the timing chain tensioner by turning the crankshaft counterclockwise while holding the wrench. This will open the timing chain tensioner.  When the timing chain is installed, it is in a closed position. You must carry this step so that the timing tensioner releases.
  18. Reinstall the serpentine belt.
  19. Do not start the engine yet. Double-check the installation by turning the crankshaft in a complete 360 turn using a 27 mm wrench at the crankshaft bolt. Do not start the engine if you cannot rotate the crankshaft by hand.
  20. Reconnect the battery.

Additional Video

Frequently Asked Question

How do you know your timing chain tensioner is terrible?

  • One of the common symptoms of timing chain tensioner problems is a tapping noise when you start the engine in the morning, which goes away after a while.

Can you drive a Mercedes-Benz with a bad timing chain tensioner?

  • It is not recommended to drive with a bad timing chain tensioner. If the tensioner or timing chain fails, it can cause catastrophic engine failure.


Mercedes-Benz vehicles are equipped with M272 and M273 engines.

We hope you find the Mercedes-Benz Timing Chain Tensioner Replacement guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.


  • Rushit Hila • ASE Certified

    Rushit Hila, an ASE-certified engineer (G1 Automotive Maintenance and Repair), brings over two decades of hands-on experience in the automotive world to his writing. With a strong educational background, including a Master of Science in Engineering and a Bachelor of Science in Engineering, he has honed his skills and expertise through years of practical work. As a respected authority in the field, Mr. Hila is dedicated to offering insightful and valuable content that resonates with both vehicle owners and mechanics.

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  1. Are you replacing the timing chain tensioner without opening the engine?

  2. John Mijares says:

    Your instructions for the w203 engine is partially incorrect as well as the type of tensioner that is used when reinstalling the tensioner.

    My 2005 clk 320 is using a different tensioner where as it comes with no adjustment or option to compress or reset the tensioner, and trying to reinstall is very difficult and takes allot of time getting started into the threaded hole, then having to use a torque wrench to screw it in. T screwing it at 1/4 of an inch at a time.

    The p/n of my tensioner is 112-050-08-11. And it is very frustrating to see that of the many videos that are being put out on you tube or instructions written, fail give the correct information or the fact that the tensioner is different, which then. Leads to the other concern of making sure the timing is set to 40 deg off TDC, AND once installed turning the crank counter clock wise so as to release the tensioner.

    How can something so different and difficult can be missed or not. Mentioned by the many who. Pride themselves of putting removal and reinstalling information on the web that to me is partially incorrect and totally be misinformation by all those who claim they a certified.

    My question to you is how does one install the type of tensioner that my car has and the one the dealer sold me?
    Isn’t it incorrect to reinstall a tensioner that can’t be compress or reset, doesn’t this cause more of a problem and can strecth the timing chain more than what is was?

    Please advise asap. As I believe I have already caused more damage to my car.

    And I don’t mean to sound disrespectful nor am I trying insult those who are experienced and who are cerrified but that information that is circulating on the web is partially wrong and puts a bit of liability on those giving the information.

    Look forward to your technical response ans. Assistance.

    1. Rushit Hila says:

      These instructions are for the M272 and M273 engines while what you need are instructions for the M112 engine. We don’t have a video for that engine but hopefully will have the step-by-step instructions up in the near future. Part numbers of course are completely different. I would recommend calling the dealer and ordering the tensioner based on the VIN.