Yea, most people do it the quick way and just replace the pulley itself. But it is a spring loaded unit. It just solves the problem temporarily. Over time the spring in the tensioner gets weak. Thats when you get the chirping noise and loud clanking noise while at a stop.

I heard some people attempted by removing the air compressor unit. Its faster that way, but you have to have a vacuum machine to suck out the freon and then recharge it after you connect it back. Something I will not attempt. I dont' want to mess up the compressor. I got on StarTek and paid for a one day subscription. The instructions to removing that belt tensioner requires removing half of the engine. Airbox, fuel rail, air intake manifold, idle control and supercharger. Once you get to the supercharger you need to lift the car up to get to two bolts. which you will need a air ratchet to break loose.

good luck. i have pictures if you need them

 

Ok I have some good news. By following information on this thread. I got the idea from here about dropping the a/c compressor. I didn't want to disconnect the a/c hoses but I sure as hell didn't want to have to take the intake and supercharger off. It took me a week to figure it out and I spent 100 bucks in tools and ended up borrowing the correct tool from a mechanic. Basically if you drop the a/c compressor take the two screws that hold the hoses at the back near the tranny it gives you enough hose movement to move the compressor down and forward about 4 to 5 inches which then gives you enough room to go up from underneath. I have small hands, I was able to reach in with my right hand by putting it behind the stabilizer bar and holding the wrench on the screw and then putting in my left hand around the same place and pulling with my left hand while stabilizing the wrench with my right hand. I used a snap on star socket because it provided the tightest fit and I also borrowed a kit that has a ratcheting wrench that fits on a piece that goes into the star socket. I ended up having to borrow this because the ratcheting mechanism on this tool is more precise which allows the tool to work in the tight environment in which you have to work. If you use anything cheap you run the risk of stripping the bolt or there is enough play in the ratcheting mechanism of the cheap ratchets that you don't have enough room to swing up and then back down. Anyways I was able to get it done by moving the compressor down without disconnecting the lines. It took a week of trial and error and I spent over 100 bucks on tools but I was able to get it done the easier way. Now that I know what it takes if you don't count the time that it takes to pull all the stuff out of the way to get the belt off, the crossover elbow and the front piece that goes to the intake, taking the screw out of the tensioner and replacing the tensioner itself can be done easily inside an hour. The a/c compressor is held only by 3 screws and you have to take off the two screws holding the hoses to the bracket near the tranny and just move it forward. You do have to have someone holding the compressor forward while you stick your hands in there and loosen the screw but it beats the hell out of taking the intake and supercharger off. The tool I used is called gearwrench serpentine belt tool 3680 by KD tools and a star socket by snapon. Hope this helps. I had originally tried to get away with just replacing the pulley on the tensioner that helped the noise for a couple of days and than it came back. What sucks about this is that i looked at the tensioner, the tensioner itseld is good what makes the noise is that in its wonderful design it has a plastic sleeve that runs inside the spring which gets brittle and flakes off so the spring twists on the metal core and causes the noise. The tensioner itself is still able to do its job, its just noisy while doing it. I thought about putting some grease on the new one to prevent this but I decided that it might end up degrading the plastic faster so I didn't do it. I hope this help is still not an easy job but it can be done. I'm hoping this one last 100,000 miles. It sure is nice to have a quiet car again.

 

thanks

 

Does anyone happen to know the torque specs on the idler and tensioner pulley bolts?
I found on a UK forum someone 'reverse-engineered' the idler pulley torque at ~40nm, but no info on tensioner pulley.
Thanks!

 

what part do I need the T 60 inverted torx bit for ?
The biggest size I have is T 55 I am only replaceing the automatic belt tensioner and it comes with the pully assembled

 

T60 torx is for the tensioner, to release the tension and slip the belt off. Some tensioners have a torx slot, some have a regular hex nut.

You can use T55 instead of T60 in a pinch, I did that twice without problems. Just be careful.

 

Good stuff thanks for the picture as well belt is already off because the pully broke and was under the engine cover

 

did u solve the rough idle when in red light with D + AC???

send me in whatsapp to add u to MB group

00971506740840

 

I am also changing the tensioner pulley only and hoping that will fix my chirping.

As VVF was asking does anyone know the torque of the bolt that attaches the tensioner pulley to the tensioner body.

I have ordered the tensioner pulley from mercedes part number A271 200 05 70 but have not been able to find the torque requird for the centre bolt

If you can help that would be great

Cheers

 

Try to call a dealer, or send an email to parts.com etc.
The idler pulley bolt torque on w204 is 26 lb-ft, so the tensioner shouldn't be too far off.
Can also check what torque you need to undo the bolt.

When does it chirp btw? When AC is on and in reverse gear? The pulley itself is not likely to fix the chirping, it might be the tensioner assembly, or something else is putting strain on the belt.

 

Thanks for the reply

I will try my local dealer to see if he can help. There are a few posts of the tensioner pulley being changed but no torque value is mentioned.

A/c on or off doesn't make any difference. Not really noticed it in reverse either (it's a manual gearbox) It doesn't chirp when started up from cold but starts chirping after a mile or two of driving. It's intermittent but is worse when the revs rise when accelerating but less noisy on the overrun if I take my foot of the accelerator.

I am hoping!! it is either the idler or tensioner pulley but will do some checks on the alternator, water pump, a/c and power steering pulleys when I get the belt off.

Cheers

 

Good luck. Maybe worn belt, too.

 

Hey guys i am new here and this is the first i have encountered the same problem as some of the guys here. My mechanic told me that my 2005 c230 needs a belt tensioner replacement. He is charging me almost 700 to do the job, parts and labor. I would just like to know if he is ripping me off or the price is just right. I appreciate your help.

 

Hey Hahaitzmickey, unfortunately my bolt for the tensioner pulley sheared off. I have removed the old one. Can you let me know how the bolt is retained within the motor? Is there a nut at the back? or something else? Will I need to pull off the supercharger to get this off?

 

So, with 156,000 miles on my ’05 C230 Coupe I now have a “noisy bearing / squealing noise” at the front of engine. I am preparing to replace all of the usual suspects (Serpentine Belt, Idler Pulley, Alternator Pulley, Water Pump, and Tensioner).

I would like to replace the entire tensioner assembly, not just the tensioner pulley. From my searches, I understand that the bolt holding the tensioner assembly in place is very difficult to access. I am hoping to use Juan Gonzalez’s approach (1-22-12 post #27 earlier in this thread) of dropping the AC Compressor (without disconnecting hoses) to gain access.

So my questions are:
1) Has anyone been successful using Juan Gonzalez’s AC Compressor drop approach?
2) Does anyone happen to know the size of the Tensioner Assembly bolt? (Again, not the pulley bolt, but the bolt holding the tensioner assy from behind). From the parts diagrams I have seen, it appears to be a ‘star headed bolt’, so it is an E-??

Thanks in advance,
Jeff

 

If the "squealing noise" sounds like a tire rubbing against a rubber floor, that's probably the sprag bearing on the alternator. Check to see if your A/C still works. If the sprag bearing goes out, it usually takes out the A/C compressor with it.

 

Where do you suggest i get the parts ?

 

Nevermind that other stupid question I searched the numbers online, but can this also work for a m272 engine I think thats the engine my 06 C230 Sport has... right?

 

Thanks for the feedback.
My noise began about a month and a half ago as a rattlely bearing noise. Some days were worse than others; some days very little noise.
It has now progressed to an RPM related whirring/whining noise. AC still works; so far...

With 156,000 miles on the clock it seems reasonable to replace the serpentine belt and related pulleys including the tensioner assembly.

So I am hoping to find out:
1) Has anyone been successful using Juan Gonzalez’s AC Compressor drop approach (post #27)?
2) Does anyone happen to know the size of the Tensioner Assembly bolt? (Again, not the pulley bolt, but the bolt holding the tensioner assy from behind). From the parts diagrams I have seen, it appears to be a ‘star headed bolt’, so it is an E-??

 

Australians - Repco sell the complete tensioner and pully for $29 and a belt for $69!! Better than genuine tensioner at $140 and MERCWRECK who wanted $185!

 

Thank you very much for this post. Clear, concise and to the point. The main reason for this message is that I just read the "Official" method for changing the tensioner pulley that involves dismantling half the engine! Your alternative (just changing the pulley) resolves 99% of all issues since the pulley bearing goes dry way before the tensioner spring ever becomes loose. I am going to order the pulley using the part number provided and go to work.