Mercedes Idler Pulley Replacement Instructions

Mercedes Idler Pulley Replacement Instructions

Updated Tuesday Jul 24, 2018

A common problem with Mercedes-Benz cars, is the idler pulley (also known as Guide Pulley or Sheave Pulley)  failing as early as 100,000 miles. Changing the idler pulley on a Mercedes-Benz is a relatively easy job for most DIYers and required less than one hour of your time. In this article, you will find step by step instructions and a video on how to change Mercedes idler pulley. 

Average cost to change Mercedes-Benz idler pulley yourself is under $50 USD. 

A bad idler pulley can cause the serpentine belt to come off. Once the belt comes off you will experience multiple problems if you continue to operate the vehicle.

  • Power steering is difficult to turn
  • Alternator stops working and no longer charges the battery
  • Battery warning light on the dashboard
  • Air Conditioner stops working
  • Engine Overheats
  • Engine stalls once the battery is drained

At the early stage indicating that the idler pulley is failing, you will only hear a squeaky noise coming from the front of the engine. Inspect the idler pulley if you hear noise from the engine. The noise can be described as whining. Remove the serpentine belt and check the idler pulley for play or noise by spinning it by hand. You should replace a bad idler pulley immediately, to avoid future problems caused by complete idler pulley failure.

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1.  Mercedes Idler Pulley Replacement Video 

The following video demonstrates how to change the idler pulley on Mercedes-Benz vehicles with 6, 8 and 12 cylinder engines. 

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2. What you will need

Parts

Tools

Note that the older models Mercedes-Benz engines require a Torx Bit Socket. This is common on M112 and M113 engines from 1997 to 2007. Newer Mercedes-Benz idler pulleys (on M272 and M273 and newer models) require female Torx socket. Always verify by inspecting the bolt on the center of your idler pulley.  

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3. Step-by-step Instructions

  1. Park your Mercedes-Benz on an area where you can work. If the idler pulley failed while you were driving it is possible to change it on the road. You need to make sure you are working in a safe area. 
  2. Allow the engine to cool down for at least 30 minutes. 
  3. Pull the hood release under the dashboard on the driver's side. 
  4. Locate the idler pulley at the front of the engine. 
  5. Remove the serpentine belt. Use a 17mm socket and ratchet on the tensioner nut to unload the tensioner. release tensioer to replace mercedes idler pulley

     

  6. Use a pin to lock the tensioner in the pre-loaded position. You can use a nail or a 5mm Allen wrench as a pin. For more help follow this guide on how to remove Mercedes-Benz serpentine belt. 
  7. Slide the serpentine belt off the idler pulley. It is not necessary to remove the serpentine belt completely unless you are replacing it. mercedes removing belt from idler pulley

     

  8. Use a flathead screwdriver to remove the plastic cap on the center of the idler pulley. Do NOT discard the cap because it needs to be reinstalled. 
  9. Use a T-50 torx to remove the idler pulley bolt. The bolt is long and requires patience to remove. Some models require female Torx socket. change mercedes drive belt idler pulley

     

  10. Install the new idler pulley and tighten the bolt to Mercedes-Benz specifications. 
  11. Install the dust cap. 
  12. Turn the idler pulley by hand to make sure it is spinning freely. 
  13. Reinstall the serpentine belt. If the belt is not long enough to slide over the tensioner pulley, make sure it sits properly in all the various pulleys. mercedes idler pulley and serpentine belt installation

     

  14. Use your 17mm socket and ratchet to move the tensioner upward in order to remove the locking pin. 
  15. Slowly load the tensioner. 
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4. Mercedes Idler Pulley Torque Specifications 

Typical Mercedes-Benz idler pulley bolt torque: 

  • Newton-meters  35 Nm 
  • Foot-pounds:   25.81 ft-lb

There is a lot of confusion on many Mercedes-Benz online communities regarding the recommended torque for the idler pulley. We strongly recommended that you verify the correct torque specs by calling your Mercedes-Benz dealer because these values can vary.

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5. Notes

  • It is recommended (not required) to change the tensioner at the same time you change the idler pulley. 
  • If your vehicle has a viscous fan, it may need to be removed to access the idler pulley. Common on pre-2000 models. 
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6. Mercedes Idler Pulley Part Number

Below you will find part numbers for some of the most common Mercedes-Benz idler pulleys. 

MODELS PART NUMBERS
  • 2005-10 Chrysler 300 V6 3.5L
  • 2005-10 Chrysler 300 V6 2.7L
  • 2004-08 Chrysler Crossfire Idler Pulley
  • 2009-10 Dodge Challenger V6 3.5L
  • 2006-10 Dodge Charger V6 3.5L
  • 2006-10 Dodge Charger V6 2.7L
  • 2005-08 Dodge Magnum V6 2.7L
  • 2005-08 Dodge Magnum V6 3.5L
  • 2003-06 Dodge Sprinter Van Idler Pulley
  • 2007 Mercedes Benz C230 Idler Pulley
  • 2001-05 Mercedes Benz C240 Idler Pulley
  • 1998-00 Mercedes Benz C280 Idler Pulley
  • 2001-05 Mercedes Benz C320 Idler Pulley
  • 1998-00 Mercedes Benz C43 AMG Idler Pulley
  • 2000-06 Mercedes Benz CL500 Idler Pulley
  • 2001-02 Mercedes Benz CL55 AMG Idler Pulley
  • 1998-05 Mercedes Benz CLK320 Idler Pulley
  • 1999-02 Mercedes Benz CLK430 Idler Pulley
  • 2003-05 Mercedes Benz CLK500 Idler Pulley
  • 2001-05 Mercedes Benz CLK55 AMG Idler Pulley
  • 1998-05 Mercedes Benz E320 Idler Pulley
  • 1998-02 Mercedes Benz E430 Idler Pulley
  • 2003-05 Mercedes Benz E500 Idler Pulley
  • 1999-02 Mercedes Benz E55 AMG Idler Pulley
  • 2002-05 Mercedes Benz G500 Idler Pulley
  • 1998-03 Mercedes Benz ML320 Idler Pulley
  • 2003-05 Mercedes Benz ML350 Idler Pulley
  • 1999-01 Mercedes Benz ML430 Idler Pulley
  • 2002-05 Mercedes Benz ML500 Idler Pulley
  • 2000-03 Mercedes Benz ML55 AMG Idler Pulley
  • 2000-06 Mercedes Benz S430 Idler Pulley
  • 2000-06 Mercedes Benz S500 Idler Pulley
  • 2001-06 Mercedes Benz S55 AMG Idler Pulley
  • 1999-06 Mercedes Benz SL500 Idler Pulley
  • 2001-04 Mercedes Benz SLK320 Idler Pulley

0002020919,


000 202 09 19,
04593848AA,

04792836AA,
68020888AA

 

Engines:

M112 and M113

  • 2008-2009 MERCEDES-BENZ C230 4MATIC SEDAN 4-DOOR
  • 2008-2009 MERCEDES-BENZ C230 BASE SEDAN 4-DOOR
  • 2006-2007 MERCEDES-BENZ C230 SPORT SEDAN 4-DOOR
  • 2010-2010 MERCEDES-BENZ C250 4MATIC SEDAN 4-DOOR
  • 2010-2010 MERCEDES-BENZ C250 BASE SEDAN 4-DOOR
  • 2009-2010 MERCEDES-BENZ CL550 4MATIC COUPE 2-DOOR
  • 2007-2008 MERCEDES-BENZ CL550 BASE COUPE 2-DOOR
  • 2006-2009 MERCEDES-BENZ CLK350 BASE CONVERTIBLE 2-DOOR
  • 2006-2009 MERCEDES-BENZ CLK350 BASE COUPE 2-DOOR
  • 2007-2009 MERCEDES-BENZ CLK550 BASE CONVERTIBLE 2-DOOR
  • 2007-2009 MERCEDES-BENZ CLK550 BASE COUPE 2-DOOR
  • 2007-2010 MERCEDES-BENZ CLS550 BASE SEDAN 4-DOOR
  • 2007-2007 MERCEDES-BENZ E280 4MATIC SEDAN 4-DOOR
  • 2007-2007 MERCEDES-BENZ E280 BASE SEDAN 4-DOOR
  • 2008-2009 MERCEDES-BENZ E300 4MATIC SEDAN 4-DOOR
  • 2006-2011 MERCEDES-BENZ E350 4MATIC SEDAN 4-DOOR
  • 2006-2009 MERCEDES-BENZ E350 4MATIC WAGON 4-DOOR
  • 2011-2011 MERCEDES-BENZ E350 4MATIC WAGON 4-DOOR
  • 2011-2011 MERCEDES-BENZ E350 BASE CONVERTIBLE 2-DOOR
  • 2010-2011 MERCEDES-BENZ E350 BASE COUPE 2-DOOR
  • 2006-2011 MERCEDES-BENZ E350 BASE SEDAN 4-DOOR
  • 2006-2006 MERCEDES-BENZ E350 BASE WAGON 4-DOOR
  • 2011-2011 MERCEDES-BENZ E350 BLUETEC SEDAN 4-DOOR
  • 2010-2011 MERCEDES-BENZ E350 ELEGANCE SEDAN 4-DOOR
  • 2010-2010 MERCEDES-BENZ E350 SPORT SEDAN 4-DOOR
  • 2007-2011 MERCEDES-BENZ E550 4MATIC SEDAN 4-DOOR
  • 2011-2011 MERCEDES-BENZ E550 BASE CONVERTIBLE 2-DOOR
  • 2010-2011 MERCEDES-BENZ E550 BASE COUPE 2-DOOR
  • 2007-2011 MERCEDES-BENZ E550 BASE SEDAN 4-DOOR
  • 2009-2011 MERCEDES-BENZ G550 BASE SPORT UTILITY 4-DOOR
  • 2007-2011 MERCEDES-BENZ GL450 BASE SPORT UTILITY 4-DOOR
  • 2008-2011 MERCEDES-BENZ GL550 BASE SPORT UTILITY 4-DOOR
  • 2010-2011 MERCEDES-BENZ GLK350 4MATIC SPORT UTILITY 4-DOOR
  • 2010-2011 MERCEDES-BENZ GLK350 BASE SPORT UTILITY 4-DOOR
  • 2006-2011 MERCEDES-BENZ ML350 4MATIC SPORT UTILITY 4-DOOR
  • 2009-2011 MERCEDES-BENZ ML350 BASE SPORT UTILITY 4-DOOR
  • 2010-2011 MERCEDES-BENZ ML350 BLUETEC 4MATIC SPORT UTILITY 4-DOOR
  • 2010-2011 MERCEDES-BENZ ML350 SPORT AMG SPORT UTILITY 4-DOOR
  • 2008-2011 MERCEDES-BENZ ML550 BASE SPORT UTILITY 4-DOOR
  • 2006-2011 MERCEDES-BENZ R350 4MATIC WAGON 4-DOOR
  • 2008-2011 MERCEDES-BENZ R350 BASE WAGON 4-DOOR
  • 2010-2011 MERCEDES-BENZ R350 BLUETEC 4MATIC WAGON 4-DOOR
  • 2009-2009 MERCEDES-BENZ S450 4MATIC SEDAN 4-DOOR
  • 2007-2011 MERCEDES-BENZ S550 4MATIC SEDAN 4-DOOR
  • 2007-2011 MERCEDES-BENZ S550 BASE SEDAN 4-DOOR
  • 2007-2011 MERCEDES-BENZ SL550 BASE CONVERTIBLE 2-DOOR
  • 2009-2011 MERCEDES-BENZ SLK300 BASE CONVERTIBLE 2-DOOR
  • 2005-2011 MERCEDES-BENZ SLK350 BASE CONVERTIBLE 2-DOOR

A272 202 10 19  

supersede 

A2722020000 

2722021019,

A2722021019,

Engines

M272 and M273


 

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