How to replace serpentine drive belt ?
 

I am planning to replace my serpentine drive belt. I understand all I need to do is loosing the tensioner pulley and pop and remove the old belt. But I have the following question need to be clear before I do it -
1. Do I need to remove the cooling fan blade?
2- Do I also need to remove the kompressor drive belt in order to replace the serpentine belt?

Any input or suggestion will be appreciated.
Thanks in advance.

The answer to your question depends on what year and model of Mercedes you have. The older E series cars (190, 300 and 320) were fitted with a belt tensioner that required you to loosen a lock nut on the tensioner and then release belt tension by backing off an adjustment bolt. The newer cars use a simpler arrangement where the tensioner is just a spring loaded pulley mounted eccentrically. To loose the tensioner, just use a ratchet and a 15mm socket to "wind up" the tensioner while you remove the belt at the same time.

None of the above cars require that you remove any of the accessories in order to change out the belt.

On the last Saturday, I finally make time to replace the serpentine drive belt. It was real easy; all you need to do is using the wench and pull the tension roller to counter clock-wise to release the tension. But you also remove the kompressor drive belt prior to replace the serpentine drive belt and it took me half an hour to complete and this is really easy to do it you self. I just want to share my experience.

For future reference...
 

what MB model are you talking about?
Thanks!

That is the 1999 C230 (W202 Chassis).

I just replaced the belt on my 86 300E last night. I removed the fan blade (three allen wrench bolts) and loosened the fan shroud. The belt tension pulley is spring loaded and I just put pressure on the old belt and pulled it off. Did the same with the new belt. The diagram in the owners manual is a big help.

Same question, different car. I have a 87 190e 16v.

Errosi mentioned a lock nut and the adjustment bolt. I see a bolt (I think it goes to the tensioner) to the tensioner on the front left of the engine beside the air cleaner. When I look at it it looks like a long(ish) tube (2 or 3 inches) hollow on the inside with a bolt at the bottom.

Also, does someone have a diagram of the path of the belt?


Thanks

David

i have loosened the alternator. Many here say that if you loosen the tensioner, and it has some age on it... you will wind up replacing it.

I did it without removing the fan or shroud.... never again that way... i think the doing it after removing the fan would make it a piece of cake.

If you don't have your belt diagram, make a drawing of it before you remove it. Yes, the long tube is the adjusting nut....BUT, before you loosen or tighten the adjusting nut, loosen the large lock down bolt on front of the belt tensioner.

http://i179.photobucket.com/albums/w...d/HPIM3117.jpg

Anyone have a better picture of this lock down bracket? Does anyone know if existes on a 190E 16V?

I was looking at mine with a flash light (not a very good view) and did not see anything that looked like what was in the picture.

I remember seeing it new and I do not remember seeing it with that front bracket.

I purchased 2 of these tensioner assemblies from MB and they come with a new bracket, bolt, adjusting rod and clip in the box.

SLK,

Thanks a bunch for your help. Once I got the fan and shroud off I saw the lock nut you mentioned. Got the job done in about an hour.

How do I tell if the belt is tight enough or too loose? I do not have the little gauge thing they mentioned in the shop manual (it does not cover the 16V engine). I can push down on it a bit When I started the car nothing squeaked, when I turned on the A/C also no squeak but I noticed the little arrow on the tension pulley was damn near it's stop.

Thanks again for your info.

David