Mercedes-Benz Belt Tensioner Replacement Guide

Does your Mercedes-Benz difficult to start, has a loose engine belt, and you hear screeching noises? The problem may be a worn belt tensioner. 

Replacing the belt tensioner on a Mercedes-Benz is easy and takes about one hour. Follow the video and steps below to learn how to replace a Mercedes-Benz serpentine belt tensioner. 

What will you need

• Mercedes-Benz Belt Tensioner
• 17mm socket
• Female Torx Socket Set
  • (E10 or E12)
• Ratchet Wrench
• 2″ Ratchet Extension
• Metal Pin
  • Use a nail or 5mm Allen key

Optional

• Mercedes Serpentine Drive Belt
  • While it is not required to replace the drive belt, it makes sense to replace it simultaneously as the tensioner. It is ok to reuse the old belt if it does not show wear, cracking, degradation, or drying.

Procedure

1. Park, the Mercedes-Benz, set the parking brakes and allow the engine to cool down.
2. Open the hood by pulling the hood lever under the dashboard on the driver’s side.
3. Use a 17mm socket to move the tensioner up (service) position.
4. Insert a metal pin in the tensioner hole to keep the tensioner up. A 5mm Allen wrench or bolt can be used as a pin. The pin needs to be strong enough to withhold shear force. Do not use any item made of plastic as a pin.
5. Slide the drive v poly belt away from the tensioner.
6. Remove the top Torx bolt using an E12 Torx socket and a 2″ extension.
7. Remove the lower Torx bolt.
8. Some models also have a shock attached to the tensioner. Remove the upper bolt from the shock to disconnect it from the engine block.
9. Install the new timing belt tensioner. Start threading the tensioner bolts by hand until a few threads have gone in.
10. Torque the tensioner bolts to the recommended manufacturer specifications. Typical torque for the tensioner bolts ranges between 25Nm to 35 Nm. Check with your dealer.
11. Install the drive belt. Make sure it is routed on all the pulleys properly. If the belt does not reach, ensure it is not sitting on top of one of the pulleys.
12. Put pressure on the tensioner’s 17mm head to move the tensioner up and remove the locking pin.
13. Start the engine and ensure the belt and tensioner are working properly.

Over time the tensioner pulley can start to crack. If not replaced on time, it can fail while the engine is running. The drive belt will come off the various pulleys, possibly causing damage. The tensioner pulley bearing may also fail. When this happens, you normally hear noise from the front of the engine.

Replacing the drive belt tensioner on the Mercedes-Benz engine is relatively easy. It requires a few basic tools and approximately thirty minutes.

This guide applies to the majority of Mercedes-Benz cars. The procedure is the same for many engines, including M112, M113, and M273.

The average price to change the belt tensioner at the dealer ranges from $400-$650. Local repair shops will charge between $280-$450. The DIY cost to change the Mercedes-Benz drive belt tensioner ranges between $50-$120, even if you have to buy the tools needed for this job and a new serpentine belt.

PART NUMBER	FITMENT
1122000970 Interchange Part Numbers 112 200 09 70 0002020019 5096525AA, 68020888AA, A0002020919, 38174 49262 89335 1122000070, 1122000170, 1122000370, 1122000870,	Interchange Part Numbers	2001 – 2005 C240 1998 – 2000 C280 2001 – 2005 C320 1998 – 2000 C43 AMG 2005 – 2006 C55 AMG 2000 – 2006 CL500 2001 – 2002 CL55 AMG 2003 – 2006 CL55 AMG 1998 – 2005 CLK320 1999 – 2003 CLK430 2003 – 2006 CLK500 2001 – 2006 CLK55 AMG 2006 CLS500 2006 CLS55 AMG 1998 – 2004 E320 2005 E320 4Matic 2005 E320 Base 1998 – 2002 E430 2003 – 2006 E500 1999 – 2002 E55 AMG 2003 – 2006 E55 AMG 2002 – 2008 G500 2005 – 2011 G55 AMG 1998 – 2003 ML320 2003 – 2005 ML350 1999 – 2001 ML430 2002 – 2007 ML500 2000 – 2003 ML55 AMG 2006 – 2007 R500 2006 S350 2000 – 2006 S430 2000 – 2006 S500 2001 – 2002 S55 AMG 2003 – 2006 S55 AMG 1999 – 2006 SL500 2003 – 2008 SL55 AMG 2001 – 2004 SLK320 2005 – 2010 SLK55 AMG
Interchange Part Numbers
2722000270 (272 200 02 70)	06 – 07 MERCEDES-BENZ C230 2.5L 2496CC V6 DOHC 06 – 06 MERCEDES-BENZ C280 3.0L 2996CC 183CU. IN. V6 06 – 07 MERCEDES-BENZ C280 3.0L 2996CC 183CU. IN. V6 DOHC 06 – 07 MERCEDES-BENZ C280 3.0L 2996CC V6 DOHC 10 – 11 MERCEDES-BENZ C300 3.0L 2996CC 183CU. IN. V6 DOHC 08 – 12 MERCEDES-BENZ C300 3.0L 2996CC V6 DOHC 10 – 11 MERCEDES-BENZ C300 3.5L 3498CC 213CU. IN. V6 DOHC 06 – 09 MERCEDES-BENZ C350 3.5L 3498CC 213CU. IN. V6 DOHC 06 – 11 MERCEDES-BENZ C350 3.5L 3498CC V6 DOHC 07 – 10 MERCEDES-BENZ CL550 5.5L 5461CC V8 DOHC 06 – 09 MERCEDES-BENZ CLK350 3.5L 3498CC 213CU. IN. V6 DOHC 06 – 09 MERCEDES-BENZ CLK350 3.5L 3498CC V6 DOHC 07 – 09 MERCEDES-BENZ CLK550 5.5L 5461CC V8 DOHC 06 – 10 MERCEDES-BENZ E350 3.5L 3498CC 213CU. IN. V6 DOHC 06 – 10 MERCEDES-BENZ E350 3.5L 3498CC V6 DOHC 07 – 12 MERCEDES-BENZ GL450 4.6L 4663CC V8 DOHC 07 – 09 MERCEDES-BENZ GL450 4.7L 4663CC 285CU. IN. V8 DOHC 08 – 12 MERCEDES-BENZ GL550 5.5L 5461CC V8 DOHC 10 – 12 MERCEDES-BENZ GLK350 3.5L 3498CC V6 DOHC 10 – 11 MERCEDES-BENZ ML350 3.0L 2987CC V6 DIESEL DOHC TURBOCHARGED 07 – 11 MERCEDES-BENZ ML350 3.5L 3498CC 213CU. IN. V6 DOHC 07 – 11 MERCEDES-BENZ ML350 3.5L 3498CC V6 DOHC 10 – 11 MERCEDES-BENZ ML350 5.5L 5461CC 333CU. IN. V8 DOHC 08 – 11 MERCEDES-BENZ ML550 5.5L 5461CC V8 DOHC 07 – 11 MERCEDES-BENZ S550 5.5L 5461CC V8 DOHC 07 – 08 MERCEDES-BENZ SL550 5.5L 5461CC V8 DOHC 06 – 08 MERCEDES-BENZ SLK280 3.0L 2996CC V6 DOHC 09 – 11 MERCEDES-BENZ SLK300 3.0L 2996CC V6 DOHC 05 – 09 MERCEDES-BENZ SLK350 3.5L 3498CC 213CU. IN. V6 DOHC 05 – 11 MERCEDES-BENZ SLK350 3.5L 3498CC V6 DOHC
2712000270	03-05 Mercedes-Benz C230 Kompressor 1.8L

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