Mercedes-Benz Parts Catalog Mercedes-Benz Accessories Catalog Mercedes-Benz Technical Articles Mercedes-Benz Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
Get FREE Ground Shipping with the purchase of $75 in qualifying parts!
 

Bookmark and Share

 


Pelican Technical Article:
Serpentine Belt Replacement

Jared Fenton
 

 
Time: 30 minutes
Tab: $60
Talent:  
Tools:
15mm wrench, screwdrivers
Applicable Models:
W210 E320 (1996-97)
Parts Required:
New belt
Hot Tip:
Check the belt for wear
Performance Gain:
Quieter belts
Complementary Modification:
Replace belt tensioner
 
   

   

Check out some other projects from our technical library: 

Need to buy parts for this project? Click here to order!
   
     One of the routine maintenance items that you should perform on your Mercedes-Benz is the checking and replacement of your serpentine belt. The belt is driven off of the crankshaft and turns the water pump, fan clutch, alternator, and air conditioning compressor. The belt should be checked periodically (every 3,000 miles, or when you change your oil).

     The M104 engine uses what is known as a poly-ribbed belt (having many channels or ribs on the underside of the belt). The poly-ribbed belt setup utilizes a spring-loaded belt tensioner pulley that provides the proper tension for the belt at all times, making adjustment unnecessary.

     When inspecting your belt, the one thing that you want to look for is cracks on the underside of the belt. If you see any cracks at all, you should replace your belt immediately. On the outside of the old belt will be a number that indicates the width and the length of the belt. Use these numbers when ordering a new belt to make sure the replacement is the same as the old one.
Remove the two spring clips that hold the fan shroud in place on the top of the radiator support (green arrows).
Figure 1
Remove the two spring clips that hold the fan shroud in place on the top of the radiator support (green arrows). Pull the coolant line going to the expansion tank out of its groove on the fan shroud (purple arrow) and carefully pull the fan shroud up and out of the engine compartment. This will give you a bit more room to work with. Also remove the black plastic cover on the front of the valve cover (red arrow).
Large Image | Extra-Large Image
Locate the serpentine belt tensioner to the left of the radiator fan.
Figure 2
Locate the serpentine belt tensioner to the left of the radiator fan. Use a 15mm socket to rotate the tensioner pulley clockwise. This will loosen the serpentine belt and allow you to remove the belt from the alternator pulley. In this picture, you are looking down at the ratchet sitting on the tensioner nut. Now remove the old belt.
Large Image | Extra-Large Image
Route the new belt (purple arrow) over the various pullies on the engine (green arrows).
Figure 3
Route the new belt (purple arrow) over the various pullies on the engine (green arrows). It helps to route it in such a way that you can quickly rotate the belt tensioner clockwise and slip it up over the tensioner. Once in place, release the tensioner.
Large Image | Extra-Large Image
In thisPicture, you can see the routing of the belt (purple arrow).
Figure 4
In this picture, you can see the routing of the belt (purple arrow). Note that in this picture, the radiator and most of the front components of the engine have been removed. Also visible is the 15mm bolt in the center of the belt tensioner (green arrow).
Large Image | Extra-Large Image
Need to buy parts for this project? Click here to order!
Bookmark and Share
Comments and Suggestions:
usaims Comments: There is a larger nut next to the pulley, it is kind of hidden - I think you should use that to reduce the tension to remove the belt. It is SO MUCH EASIER!
June 7, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Pete Comments: T was unable to remove the fan cover on my 1993 300E as per your instructsions, The fan prevented removal.Any other instruction on remoing the fan cover? I need to remove the alternator.
April 24, 2014
  Followup from the Pelican Staff: This article applies to:
W210 E320 (1996-97)


You may have to remove your mechanical fan to get your shroud off.
- Nick at Pelican Parts
 
97E320 Comments: Correction: I thought I knew what I was doing and I'm smart enough to ***stop when something is not easy***. Consult this article.
April 6, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
97E320 Comments: I used a couple articles from you now. I will buy some parts now. Thank you! My Story: I was trying to turn the tensioner counterclockwise.

I thought I knew what I was doing and I'm smart enough to stop when something is easy.

Critical points:
0. Turn the tensioner ***Clockwise*** to release. About 60 ft lbs of torque to move it in my estimation. It should move freely.
1. Make a drawing first
2. Have a bright flashlight
3. Have this article ready.
4. measure the old belt against the new one, they should seem similar with the new one being potentially slightly smaller. If you have the wrong belt, you will know it. I fyou ahve that thought like, "um... that's odd", you probably have the wrong belt. Have a second car ready.

I have found that I got the belt on more easily by doing all but the tensioner at first, however to get the tensioner socket on you can't stretch a new belt that far. So... At that point, remove the far left end, alternator see picture 4 of write up. Then when you roll on the tensioner all the way to the stops, you can slip the belt over the alternor and it's guide above and right 1 position. It's not super easy and you kind of have to massage it over the ribs of the alternator, but it was WAY easier than any other options I could see, considering you have to have a wrench on the tensioner to do this.

Also, I pushed the socket wrench with my right hand, knuckles near the radiator. Left hand to set the belt and remove it from the alternator. Guess what? One little bump and 4 razor slices in my right hand knuckle. Mechanics gloves might be a good idea, especially with a car like mine. Her name is LaFawnDuh, she's a little bitchy, and bites. :- See picture, attached.

I checked all pulleys with a fresh LED maglight. My 10 year old daughter then repeated with her hands to feel that they were all seated and get a little dirty.

1/2 Turn over, do not start. Check the whole belt again.

Test start. Should be really quiet compared to before, nearly no noise is good.

Stop. Check the whole belt again for abnormal wear, lines, damage, check each pulley with a bright flashlight.

Test drive and enjoy the $120 in labor you just saved. Consider doing your own brakes now. There's another good article on this site and it's super easy, as with most maintenance jobs on Mercedes. Mercedes are super well engineered for maintenance.
April 6, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. Glad we could help.
- Nick at Pelican Parts
 
carlos Comments: HELP. 1997 and 1998 with A/C.

1- Are the 1997 and 1998 serpentine routing the same.
2- Are the belt tensioners the same for both years?
3- Is the serpentine belt the same for both years?
March 31, 2014
  Followup from the Pelican Staff: This article does not apply to 1998 models. - Nick at Pelican Parts  
97-320 Comments: your advice needed on changeng 97\320 bayrings
March 28, 2014
  Followup from the Pelican Staff: I don't understand the question - Nick at Pelican Parts  
Steven Comments: Jemmy I'd love to see what you did!
March 27, 2014
  Followup from the Pelican Staff: Hopefully Jemmy will share the tool. - Nick at Pelican Parts  
shad Comments: Im
Hearing voices from my engine. And we isolated the problem as being the air conditioner compressor pully. But it need time to order and i need to use my car. So i was wondering if there is a way or lets say a special configeration that allows me to run my engine but isolate the pully of the ac. Maybe using a shorter belt. Of course temporarely for the new parts to b available. If anyone could help plz
March 15, 2014
  Followup from the Pelican Staff: If your model was available without A/C, you can install that belt. You may have to install a pulley to bypass it. Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
Rev Ron Comments: I got huge problem with my 2006 Ford f150 5.4 triton engine. Engine light came on saying 7 and 8 injector bad. I replaced and now its running even worse. Help
March 2, 2014
  Followup from the Pelican Staff: I would check that the injector wiring is not shorted or faulty. You may also have an issue with a different engine component causing the rough running. - Nick at Pelican Parts  
rev ron Comments: First Mercedes I have ever worked on. Pelican was a great help in my changing of serpentine belt. Would help if you had a diagram of belt pattern.
March 1, 2014
  Followup from the Pelican Staff: We do not have a diagram for the belt.

Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Wenzel1220 Comments: Is there a diy guide for a 97 E 420 serpentine belt swap? Also what else should I check while doing this?

Thank you
March 1, 2014
  Followup from the Pelican Staff: We don't currently have that tech article. If we get the chance to perform the repair, we will be sure to document the process.

Applicable Models:
W210 E320 (1996-97) - Nick at Pelican Parts
 
71LS5 Comments: When replacing the belt on a '97 E320, should I also replace the tensioner and pulley and the idler pulley?
November 4, 2013
  Followup from the Pelican Staff: I would inspect them and see if the bearings feel smooth and are quiet. If there is any doubt, replace them - Nick at Pelican Parts  
Rowdy Comments: Do you have a photograph of a 1991 300sl serpentine belt and belt tensioner and how to replace?
September 30, 2013
  Followup from the Pelican Staff: Look in our tech forums and the procedure and digram are both in there. You need to follow the routing for the 104 engine - Kerry at Pelican Parts  
Dave Comments: I have a 86 MB 300E, I am trying to replace the serpentine belt but the one shows will fit this vehicle, seems not to fit. Any comments or suggestions??? Thank you
September 2, 2013
  Followup from the Pelican Staff: This tech article does not apply to your vehicle. I attached a diagram that should be similar to your vehicle.
Give our parts specialists a call at 1-888-280-7799. They can help you find the right belt.- Nick at Pelican Parts
alex Comments: hi i have a 1998 Mercedes-Benz CLK320 Coupe and need to replace both fan belts but i dont have a diagram of which belt goes where theres two belts 1 small 1 large if i could get a diagram of one with the small belt on and one with larger belt on i would be appreciated thanks in advance Alex from Australia
August 5, 2013
  Followup from the Pelican Staff: Can you use the photo from diagram 4 to help with the belt routing. - Kerry at Pelican Parts  
bg Comments: What causes this belt to break. It was a new belt
July 1, 2013
  Followup from the Pelican Staff: Without personally inspecting the vehicle, all I can do is guess..

IMO: There is "NO" common serpentine belt design flaw on this engine, you "MUST" inspect all possible causes every time.

A damaged:
* Belt tensioner or pulley
* Idler pulley
* Water pump
* Alternator
* Power steering pump
* A/C compressor

Other possible causes:
* Incorrect belt installed
* Defective belt
* Incorrect belt routing
* Damaged or defective harmonic balancer
* Bad engine mount
* Vehicle modification
* Road debris
* Broken timing cover
* Sabotage

-whunter-
 
Chris Comments: Replaced serpentine belt on 1999 c280 Mercedes Benz and it shredded again within 2 days of repair. There is a fluid leaking could it be power steering fluid ? Any suggestions what could be causing belt to shredd.
June 25, 2013
  Followup from the Pelican Staff: Sorry, this requires LOCAL hands on diagnosis, before the engine is damaged.
-whunter-
 
Jemmy Comments: On my car it is a 19mm bolt,and it is hellisly tight! I have a 190E 1.8 1993 Merc manual,and I snapped off the 13mm tensioning bolt,as it had seized,so had to make up a new tensioning device, which works well.If anyone wants some advice,please mail me.
May 20, 2013
  Followup from the Pelican Staff: Usually the excess tension is caused by corrosion, glad you resolved the issue.
- whunter
 
samrethy sok Comments: question, How can i get the 15 mm torx socket?
April 25, 2013
  Followup from the Pelican Staff: If you must have it today, most retail tool and car part stores carry this.

We have it in many sets.
http://www.pelicanparts.com/Mercedes-Benz/catalog/ShopCart/TOOL/POR_TOOL_WTD166-detail.htm

roy@pelicanparts.com
 
skinny Comments: how about a "sticky" on year2000 e320 with ONE drive fan electric in back of radiator
September 5, 2012
  Followup from the Pelican Staff: I will see what can be done.

- whunter
 

Check out some other sample projects from the book: 

 

Got more questions?  Join us in our Mercedes Benz Technical Forum Message Board and ask a question to one of our many automotive experts.

Or, see what other questions readers have asked about this article...
  Applies to: 1992 300SE, 1993 300SE, 1993 300E, 1994 C280, 1995 C280, 1996 C280, 1997 C280, 1995 C36, 1996 C36, 1997 C36, 1994 E320, 1995 E320, 1994 SL320, 1995 SL320, 1996 SL320, 1997 SL320, 1994 S320, 1995 S320, 1996 S320, 1997 S320, 1998 S320, 1999 S320, 1990 300CE, 1991 300CE, 1992 300CE, 1990 300SL, 1991 300SL, 1992 300SL, 1993 300SL
  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping]

Copyright Pelican Parts Inc. -    DMCA Registered Agent Contact Page