Glyn M Ruck

I'm a person that fixes things immediately. But the attitude of "let it develop" only works for me if the noise is correctly diagnosed. Then you can make an informed decision. e.g. will it leave me stranded somewhere or is it jusy an irritation.

Back to the 6 buck stethescope.

At least yours sounds external. I've been working with 320Make from Finland on PM and his knock is now down to a small-end bearing or piston slap on one bank of the engine. It's getting expensive quickly now. I believe he has a damaged piston - thrust side skirt!!

Does the noise still go away as the car warms up?

04mbc230

Nope, I don't think it did. It remains on the low rpm side. I think I had warm it enough after driving it on a freeway run. I went home and manuever the car back in place and still hear the knocking when ever I turn the steering wheel to either side. I also tend to hear the knock for 2 secs when I step on the pedal and once it past 1000 rpm, it is quiet.

I am wondering if this has to do with the idle pulley, tensioner pulley or the alternator I had been reading lately. The thing is, the member who fixed this and recorded the sound didn't match mine at all. His is a screech vs mine is an diesel engine knock.

I think I will just have these parts change out to be safe. I have a feeling that it must be one of those items since I did change out the belt and I am sure the MBtech had tighten up the tensioner or pulley and now the knocking went away or not as apparent.

04mbc230

Okay. The noise is still there, so now I doubt it has anything to do with the water pump or the belt. Well, at least I had taken care of the water pump since that is starting to fail.

As far with the noise, it's there back with a vengence. It there on cold start up and goes away when it's warm. It there now on low rpm on Drive or Reverse. When it's warm, I can make the noise when I turn the steering a bit or engaging the steering.

Same area, but I think has something to do with that matte I pointed on my picture and it is behind it. It looked at the area, there are the famous belt tensioner pulley and two other pulley in the area. I haven't identify the two pulleys there.

The Idle pully is not it. I can see it and it's not making noise. I do notice the belt tensioner pulley is kinda wobbing a bit.

LILBENZ230

What did it cost you to have the water pump replaced? I suspect that if the water pump being replaced did not solve the problem that it was not "starting to fail". Maybe my head's been in the sand but I've been around here and while and don't recall any water pump failures.

04mbc230

I don't know Matt. That's what the tech told me and he show me the part that was taken out. It has play on it and I do hear the squeek sound when I spin it. So perhaps a starting to fail part?

Well, I still have that disel knop knop knop sound. It does goes away when it is warm, but I can make it come to life when I turn the steering any either direction which in R or D. Durning the cold start in the morning, I can pinpoint on the driver side area as I had on the pictures. It's either the belt tensioner pulley, and 2 other pulleys in the far left driver side.

The belt tensioner pulley seems to wobble a bit, so I am saying that is a problem part perhaps.

Glyn M Ruck

I was with a retired friend for a barbeque on our Heritage Day public holiday on Friday. His MY 2000 W203 M111 engine has just done a water pump at approx 400,000 Km. Leaking front seal & noise. If coolant concentrations are maintained they certainly go a long way. That said I've seen a few at approx 120,000km. They are not a common failure & first signs are usually a coolant leak.

LILBENZ230

OP are you uncomfortable with revealing how much it cost to replace the water pump? It's cool if you are, just wondering since I've asked twice and it hasn't been acknowledged.

04mbc230

Haha No Matt, I am not uncomfortable. I remember reading about that question, but somehow never answered it when I type my reply. Weird.

I paid about $500 parts and labor. Don't know exactly the cost just for the water pump, but this is the whole thing which includes the following:

1. both L & R front arm thrust bushing

2. Drive belt

3. water pump

4. coolant

So you do you think? A fair price or overpaid?

LILBENZ230

At dealers you almost always over pay. I don't know what is fair for that, though.

04mbc230

Okay guys / gals. I got a call from my MB tech and was told that this noise is from either the Super Charge compressor pulley or the AC pulley. They recommend to replace both to fix this problem. They said, there was a car that can in for service and had the same exact sound as mine.

I have a feeling it's more of the Super Charge compressor pulley going bad.

I looked at the price for this part $1300 and the AC is $400.

Wow oh wow.. That is going to be an expensive fix just to get rid of the noise.

So what do you guys think, is this a fair price for parts? Is this worth fixing now or can I hold off a little while?

LILBENZ230

Are you taking it to the dealer? $1300 for a pulley?

04mbc230

Well, no. The tech works at the stearship. $1300 is for the whole thing and the cost to purchase the whole compressor. Pulley and all. I think the tech is suggesting to replace the whole thing to secure a fix.

So, do you think I should just replace the pulley? Can that part just be replace? Or do I have to replace the whole thing? I don't see just the pulley as a replacement though.

LILBENZ230

I would've thought the supercharger pulley could be replaced without needing to replace the supercharger itself. If that's not the case, though, I'd not spend that much money on something that isn't causing a problem. I'm assuming the car runs fine and the supercharger works fine?

I never really hear of S/C failures in these cars.

04mbc230

I agreed. Well, I have the sound posted earlier. So what do you make of it?

Yea, if the pulley is replaceable, I would just do that. I think the tech thinks it's much easier to replace the whole thing than to take out parts.

If that is not the noise, then it could be the AC compressor?

My car sounds like a disel engine in the mornings.

Glyn M Ruck

I don't think the dealer actually knows whats wrong. I4 Kompressors have no clutch to wear out. They just dump overboost. All they need now & again are new bearings & an oil change. The rotors do wear over time but this just leads to loss of boost as clearances open up. They do not lead to failure. The car just steadily looses power.

LILBENZ230

All the C230K cars sound like diesels in the morning. That's pretty normal. The knocking noise isn't but the general lawn-mower sound is normal.

bprocks

Hi, Did you ever get to figure out what the cause was? I have the exact same noise from my CLK55 (which has no SC) and am trying to find out what could be wrong. Thanks

Glyn M Ruck

Small end bearing is a possibility on the V engines. We have had 2 lately.

04mbc230

Alright, I think I can file this issue.

It's the AC compressor.

Here's another person with the same noise and resolved by changing out the AC compressor.

http://www.youtube.com/watch?v=kfBaRhc5zgw

LILBENZ230

My car has started doing this recently, I believe.. I'm gonna have to record it. Did your car only do it with the A/C compressor on, or at all times because they're not clutched?

LILBENZ230

Actually no, listening to that video again that is clearly a metallic rattle. Mine is a faint knock.. definitely hasn't always been there, I'll post up my own recording soon and we can compare. No signs of anything wrong with my car - runs/drives fine. Will be hooked up to STAR tonight so I'll see if it is storing any info.

HamTex

I also had the same annoying rattle noise coming from the engine, when it was in low rotation, but finally my efficient mechanic, after a thorough investigation, found the problem, which was:

1) Substitute the V Belt tensor
2) Substitute the tensor pulley
3) Substitute the alternator pulley

See attachments

Problem solved, it is as good as new!

Hamilton