seagel1000

Hey Guys,

I was wondering if anyone here has any instructions on how to replace the idler and tensioner pulley onthe M271 engine (1.8L Kompressor)? It has gotten pretty bad since my initial problem with rough idling and noise making with the A/C being on and sound like a metal-ish screeching type noise.

Any chance any one here has knowledge or experience in replacing both parts? Tools needed and instructions will be greatly appreciated!

Here is the closest "instructions" i've came across Searching the Forum.
https://mbworld.org/forums/c-class-w...30k-coupe.html

-Chris

rabney72

hey this sounds like the issue I'm having described here
https://mbworld.org/forums/c-class-w...ompressor.html

Is it the idler or tensioner pulley? And if it's the tensioner then mine is just the pulley and not the tensioning spring because it's still very tight.

I've got the MB service manual so I could possible tell you how to do it.

Thanks,
Robert

capt_paul

I have the same issue with the chirping noise. I replaced the idler pulley and serpentine belt and it didn't help. I purchased a tensioner pulley (the one down under the supercharger) to have Klemann replace it if necessary when I had the boost kit installed. Cory informed me theat the tensioner was nice and tight and the pulley was good to go. So I have a brand-new tensioner in my garage. I still need to find the cause of the chirping. From reading these forums, it looks lik a bad alternator sprag bearing.

rabney72

bad alternator sprag bearing...hmm, i'll have to look into that.

Thanks

LILBENZ230

Be warned that a failure of that sprag bearing WILL take out the A/C compressor. Scottisha (with his 6MT 2005 C230 @ 203k miles) had that happen a few times in a row, IIRC.

capt_paul

A little off the subject but...
I looked up part numbers for both front and rear alternator bearings for the alternator, but I wonder how difficule it is to replace it DIY or is it better to bring it to an alternator repair place.

seagel1000

Hey man! Yeah I'm experiencing the same issue. When I have the AC on, at cold starts for the first 15-20 mins, when turning my steering wheel all the way to either side (to the point where you hear the power steering at work), when rear and front defroster is on. All those functions or actions I listed will likely trigger a rough to almost severe rough idle. It seems like when ever the pulleys have a more load than normal job to do, it begins rough idling based off my basic diagnosing. I'm believing and hoping it's just a matte of replacing the idler pulley and as well as the tensioner pulley (I ordered both) willfix that specific issue. But noticeably is when my AC is on I have th car in D or R is when the noise is the loudest. A metal screeching noise or loud chirpish scratching noise.

If anyone can provide instruction on doing both pulleys, thatll be great! The idler looks easy. It seems like a simple screw at the center of the pulley is all you need to remove. The tensioner pulley is what's got me scratching my head. Don't even know where to start. Excuse my text if it's not spaced, I'm using my iPhone which fails to space words typed at times.

-Chris

TemjinX2

chris, I can help you out if you want to come down to corona.

But I would identifiy which ones are bad first. Loosen the serpentine belt so you can spin all the pullies separately. Spin each one, the pulley that make noise when you spin them are the ones that need to be replaced. Then you can just replace them all at once.

I'm usually in oc chilling with friends, if you want to meet up, but i have most of the tools at my house.

e24kgold

I had the same problem. Replaced the tensioner, idler, and alternator pulley and the problem was solved. Have fun replacing the tensioner pulley, you have to remove the supercharger, its a *****.

seagel1000

Hey Mike! How's everything going man? I'll try that when I get home from work. I'll send you a PM later in the day if I don't find your # somewhere in my past PMs!

-Chris

CoupeCrazy03

How much were these pulleys and do you have a diy to do all of it?

capt_paul

According to the MB maintenance DVD, you have to remove the supercharger, intake manifold, and associated parts to get to the 1 bolt at the back of the tensioner.

seagel1000

Yeah from what I read somewhere here, it is pretty deep in the back (requiring several other parts to be removed). Would I need to buy another gasket (SC or Manifold) or part before removing any of these parts to change out the Tensioner Pulley assembly?

seagel1000

Here are both pulleys. Cost about $107 for both.

http://www.rmeuropean.com/Part-Numbe..._85E85BAC.aspx

http://www.rmeuropean.com/Part-Numbe..._85E85BAC.aspx

(verify it's for your vehicle year/model first before purchasing)

The idler doesnt look hard at all, it is the Tensioner where the real work is.

e24kgold

No did not diy... Paid about $1000.00 for everything including labor. Labor was most expensive. Ill try to find the invoice and post

infected

The noise is coming from the alternator, no need to replace the tensioner/idler as it is a pretty big job; timing cover comes off too.
I would just replace the alternator assembly rather than fiddle with the bearing; it's not worth it.

rabney72

Dude... Is this what happened to me? Is it the wicked vibrating that cause it?

rabney72

Do all of these pulleys contribute or is one a fix? What about this sprag bearing?

rabney72

I know the tensioner pulley requires serious work but I have the DVD so I'm not worried. But first thing I want to identify before throwing parts at the car is which one is causing the noise . Is it the alternator bearing , alternator pulley, idler pulley, tensioner pulley, tensioner, or all?

seagel1000

If you're having problems with the Alternator, might as well do it all (the whole unit itself). It'll take care of the pulley, bearings and such.

I referenced my diagnostics to this thread:

https://mbworld.org/forums/c-class-w...udio-file.html

rabney72

Yah, and I can get it at the local parts store for 180$.

I just have a hard time believing that this is the issue. I mean, I never get the noise when the ac is off.

It'd be nice if someone had this issue and knew the exact solution.
I guess I can try it and if it doesn't work take it back, but it's such a pita of work....

seagel1000

LOL. Hey man, $180 isn't bad at all. Cheapest i've seen the a Alt. for (OEM BOSCH) is like $300 (with $72 dollar core included).

I personally wouldn't know what it could be but after reading many posts and threads about pulley tensioners being the "number 1" culprit for the sounds we're experiencing, I'd rather give the idler and tensioner replacement a shot before I replace an alternator.

If you can get a hold of the steps in your MB manual and hand em over to me, I'd be glad to give it a shot and see how it comes out for me. I don't think anyone else here has more problems than me as far as the noises go and the vibrations and the rough idle. All I do know is my A/C noise and rough idle at cold starts is getting worse. Eventually it seems like the car is going to need a bit of gas pedal action to keep it alive which doesn't sound like something I want to experience.

seagel1000

Oh BTW, did you check out the sound clip from that thread i just posted? Mines is the same noise (add the rough idle to it as well for me).

rabney72

Yah that's definitely the sound. Mine does it constantly though in D or R with the AC on and not moving.

rabney72

BTW the Alternator will be a lot easier to replace than the tensioner pulley as it requires the removal of the supercharger. The idler pulley should be an easy one.

I found the alternator on oreilly autopart's website for 180, probably their brand and rebuilt but, it comes with a lifetime warranty whereas the german ones dont.

I'll see what I can do about posting the instructions. (not sure how to save the program instructions to a pdf)