Bearded

Hey guys and thanks for this forum, its been a very big help to me.

I have a w203 Kompressor coupe c200 with a M271 engine and it has a really loud engine noise during idle and drive. I just finished finding and repairing my air leak causing serious performance issues but thankfully the engine is running a lot better all because of the information i found on this forum.

After I fixed my vacuum leaks I cleared my code errors and drove around for an hour and the only code I have is Cylinder 4 misfire (I think is due to my faulty coil pack and waiting for my new one to arrive). But the car has been over time Idling louder n louder and I always assumed it was due to the vacuum leak.

I'm not sure were its coming from whether its from the A/C compressor or the pulley pensioner but I have a video i"ll link in below.

Please any advice or suggestions will help me a lot. Thank you in advance

Icebreaker

How many miles on your car? It sounds like your alternator one-way pulley gave up the ghost.

Bearded

My car has 153 xxx kms or 95xxx miles , you think it might be the alternator? well I remember at around 120 XXX kms I got an error (Battery Alternator Visit Workshop) on my dash but it lasted for a minute then disappeared and never came back again. Could the alternator be the cause of a loud noise?
ps. battery is charging and voltage increases while driving

Icebreaker

No not the alternator but the alternator pulley. What happens is that the pulley has a one-way clutch (sprag) so that when on deceleration it freewheels so the alternator doesn't pull down the engine saving some gas (theoretically). When this pulley goes bad it stops freewheeling and you'll hear a noise like a chain slap or something grinding. The part looks like this on Ebay
http://www.ebay.com/itm/New-Alternat...BWOdMa&vxp=mtr
Not hard to change and I think there is a write up somewhere already as to how to change this part. You need a special too that costs about 20 bucks. No need to go out and get a $300 alternator!

Icebreaker

Here is a link to how to change this pulley.

Bearded

I checked my alternator pulley now, there is no play in the pulley or any noise coming from the bearing, I think it might be the a/c compressor and/or tensioner pulley as I noticed there is a chip on the edge of the pulley

Icebreaker

No there is no play just that the alternator can turn either way when you turn the pulley. Pulley on A/C compressor connects directly to compressor shaft as there is no clutch there. But of course if you are set on the other pulleys........

Bearded

I checked all the pulleys and the idler, tensioner and ac pulleys sound pretty bad but I'm not sure if the is giving that clock because i'm going back and forth

VVF

While the belt is off, start the car for a quick listen to confirm the noise is gone.

I would change both the idler and tensioner pulleys really, they do not sound good, and are too loose.
Not sure about the PS pump, mine makes similar sounds and no new one to compare against.
To check the alternator sprag bearing try to grab the pulley and give it some momentum in one direction and immediately try to stop it. One way it will keep rotating, and the other way it should be slipping. If it's not slipping then replace.
The ac pulley as icebreaker said is connected to the ac internals all the time, so you are hearing the pistons moving inside etc.

Bearded

I changed the belt , idler pulley , tensioner pulley but still a loud idle but there is an improvement, I made another video after the replacement and i zoomed into the ac compressor and i might be wrong but it seems like its not rotating evenly.

Icebreaker

I told you what it is but apparently you don't believe me.......

VVF

It doesn't sound like the alt pulley to me, and I had a bad one.
Another way to check is to start the car and put in Reverse with brake applied, there would be all kinds of belt squeaks and noises.

Icebreaker

I never had any belt squeals and the noise never changed for me. What was wrong with my pulley was that it locked up so it could spin the alternator in both directions (or no free wheeling in any direction).

Bearded

Alright I'll check the alternator pulley one more time, Ill Upload another video within the Hour

Icebreaker

What you can do is stick a screwdriver in one of the slots and turn the pulley in either direction, it should turn freely counter-clockwise (to the left) and not spin clockwise as the screwdriver will prevent it from doing so.
Within the hour? Does that mean you already have the alternator pulley on hand?

Bearded

No im in the engine bay now amd i placed a screw driver in the alternator slots and the pulley isnt turning either way. Am i doing it wrong?

Icebreaker

Then I have proved my point that the one-way-clutch in the pulley is bad....Replace the pulley!!

Bearded

You are 100% right, I have to admit when you said the alternator pulley I just skimmed over what you said, but when i Took it out of the car I could tell exactly what you meant. Thanks for your help.

Bearded

I was researching and I use to always hear a buzzing sound in my car but I assumed it was the aftermarket stero but further reading I found:

Rev up the engine to approximately 2000-2500 revolutions per minute (rpm). Then shut it off and listen for a buzzing sound coming from the alternator. If you hear a short buzzing sound (1 to 5 seconds), the pulley’s bearing may have worn out and the overrunning alternator pulley may require replacement.

Icebreaker

No problem buddy. Sorry you had to go though all the trouble with the other pulleys. I have 130k and all the other pulleys haven't given me any troubles yet and they all sound like yours (from the last video you made) exactly.
Don't feel bad, when mine went I also thought it was from my compressor too till I found out there is no clutch!! LOL!

Bearded

no no all good, the other pulleys were on there way out anyway. might as well replace them now before they got any worse. Thanks both of you guys for replying and helping, I really appreciate it.

Also do you have a possible link for the clutch removal tool?

Icebreaker

Here you go.

http://www.ebay.com/itm/TT-A3-VW-AUD...754767&vxp=mtr

Icebreaker

The Torx that holds the alternator shaft for my alternator is T-50 x at least 3 inches long

VVF

FYI: https://mbworld.org/forums/c-class-w...ditioning.html

I just replaced the whole alternator with a reman one.
The reasoning is, don't have to do it twice when the old alternator dies.

Icebreaker

Basically the only thing that gets worn out are the brushes. They are part of the regulator which is the component that goes bad in the alternator (normally) and only costs between 35 to 50 dollars. Alternator cost is at least twice that. Just my preference....