Drive belt noise C300 W204
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Drive belt noise C300 W204
So I had some front end noise and a worn belt. I replaced the belt, 2 pulleys and the tensioner. Put everything back together and the belt seems seated properly on all. Now I’m having noise from either the power steering pump or AC because they’re the only 2 things on that side. All the pulleys spun freely with no noise when the belt was off and I didn’t notice any play on any of them. I did notice that the tensioner seems to move/bounce a bit. The bolts are tight it’s just the tensioning part that is moving. It wasn’t doing that with the old one. Any suggestions on diagnosing this? I can make a video later and upload of that would help.
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Okay what you have is a seized up alternator drive pulley, they should freewheel one direction and drive in the other direction.
I searched for moths and replaced belt and idlers and still I had a noised which would come and go at idle and all idler pulley flapping back and forth, worse when battery voltage is low.
Replaced the idler and now no noise and tensioner idler is stable.
FYI my daughter 18 replaced mine under my tuition and coaching to gain some mechanical experience, blue sleeve and hands at end of the video.
https://www.ebay.com/itm/ALTERNATOR-...72.m2749.l2649
Also need a spline drive and Allen key
https://www.aliexpress.com/item/4001...archweb201603_
I searched for moths and replaced belt and idlers and still I had a noised which would come and go at idle and all idler pulley flapping back and forth, worse when battery voltage is low.
Replaced the idler and now no noise and tensioner idler is stable.
FYI my daughter 18 replaced mine under my tuition and coaching to gain some mechanical experience, blue sleeve and hands at end of the video.
Also need a spline drive and Allen key
https://www.aliexpress.com/item/4001...archweb201603_
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Update
So still having the belt squeak issue. Replaced the crankshaft pulley/damper. This made a slight difference but not much(although there’s noticeably less vibration when sitting at a light so that’s good!) noticed when I had the belt off that the idler pulley(the one up top that mounts to the water pump) has a tiny bit of play even when torqued down, the pulley is brand new but I guess it’s possible that it’s faulty. I’m going to get a new one just in case as they’re fairly cheap. As before all the other pulleys spin freely with no noise and no play. No issues in performance either. Steering seems fine, AC works fine, no charging issues etc. I thought to also try a new belt as well just in case the belt is bad, but it looks fine to me. Anyone had a similar issue or any advice please let me know!
Super Member
Joined: Jun 2016
Posts: 562
Likes: 75
Mercedes w204 4matic sport
So still having the belt squeak issue. Replaced the crankshaft pulley/damper. This made a slight difference but not much(although there’s noticeably less vibration when sitting at a light so that’s good!) noticed when I had the belt off that the idler pulley(the one up top that mounts to the water pump) has a tiny bit of play even when torqued down, the pulley is brand new but I guess it’s possible that it’s faulty. I’m going to get a new one just in case as they’re fairly cheap. As before all the other pulleys spin freely with no noise and no play. No issues in performance either. Steering seems fine, AC works fine, no charging issues etc. I thought to also try a new belt as well just in case the belt is bad, but it looks fine to me. Anyone had a similar issue or any advice please let me know!
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
take a long screwdriver (like 2ft long) and touch the tip on next to or on( pulley bolt) each pulley and put your ear on the handle and listen, while the car is running. Be very careful not to touch the belt doing this. The pulley noise will travel through the screwdriver and you will hear its noise, if it sounds Grindy or real high pitch the bearings could be bad on the pulley. This is an old school method of isolating noises.
Super Member
Joined: Jun 2016
Posts: 562
Likes: 75
Mercedes w204 4matic sport
i used one of those stethoscope things for that they all sounded fine even the one that had the slight play in it. My thoughts are maybe the one with the slight play is causing a slight misalignment and causing the rub somewhere else. I appreciate the suggestion though and will definitely double check them all again. That idler pulley was the first piece I changed and that’s when this all started.
Super Member
Joined: Nov 2008
Posts: 604
Likes: 29
From: SA
2008 C350-Sport-AMG-Active Agility Pack(Not reliable) +Izuzu KB6 3L(It seems Reliable)+Mazda
In my opinion the small idler pulley is the weak design of the lot, compared to the others, theres a larger pulley that is excellent design compared..
Trending Topics
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
a pulley bearing should not have any play in it. Some pulleys have a spacer washer put between the bearing and engine, was there one on the original pulley? It would be a separate piece and if you didn’t pay attention it could fall into the undercover. If you don’t transfer it( if there was one) that would cause pulley mis-alignment and play. Look up a parts diagram for the pulley.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
If you keep replacing all the parts eventually you will get to Post #2 replace the alternator pulley due seized one way bearing inside of alternator pulley.
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Alternator is fine
Alternator pulley is spinning freely with no noise in both directions when the belt is off, charging at proper voltage. Thanks for the response though!
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Hi, you have missed the point, inside of the alternator pulley (not the alternator) there is a one way sprag bearing designed to allow slippage in one direction and drive in the other direction this taking the slap and stretch out of the drive belt at idle.
The way you test if the bearing has seized is to remove the drive belt and install small screwdriver into the front of the alternator this jamming up the inner shaft from turning, at this stage the drive pulley should turn by hand in one direction and be locked in the other direction.
A failed bearing result is the pulley is locked in both directions which is what you will find with your car.
The way you test if the bearing has seized is to remove the drive belt and install small screwdriver into the front of the alternator this jamming up the inner shaft from turning, at this stage the drive pulley should turn by hand in one direction and be locked in the other direction.
A failed bearing result is the pulley is locked in both directions which is what you will find with your car.
Last edited by NZ-Merc; Mar 6, 2021 at 04:57 AM.
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Hi, you have missed the point, inside of the alternator pulley (not the alternator) there is a one way sprag bearing designed to allow slippage in one direction and drive in the other direction this taking the slap and stretch out of the drive belt at idle.
The way you test if the bearing has seized is to remove the drive belt and install small screwdriver into the front of the alternator this jamming up the inner shaft from turning, at this stage the drive pulley should turn by hand in one direction and be locked in the other direction.
A failed bearing result is the pulley is locked in both directions which is what you will find with your car.
The way you test if the bearing has seized is to remove the drive belt and install small screwdriver into the front of the alternator this jamming up the inner shaft from turning, at this stage the drive pulley should turn by hand in one direction and be locked in the other direction.
A failed bearing result is the pulley is locked in both directions which is what you will find with your car.
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
So I did as you said and sure enough the pulley is locked in both directions with the shaft blocked. Searching for one online now, or might just replace the alternator as it’s 10 yrs old at this point. Either way thanks a lot to NZ_merc! It’s funny, I had a trip to NZ planned last year, then COVID happened. If we do make it down this year I owe you a beer my friend. I’ll post an update once I swap that out. Thanks again!!
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Hi, No worries glad to help I eventually figured out the problem after replacing the belt and idler pulls to no avail then spending at least 9 months thinking of why the noise problem is worst (battery voltage low) after starting and what parts are affected then analysing the problem.
If you want to replace only the pulley it is quite easy just need to pop the black cap of the pulley and check the p/n of the original pulley mine was INA 535 0165 10 which is on ebay then I brought the two tools required from aliexpres and my 17year old daughter swapped it in over under my tuition.
Replacing the alternator has its merit depending on milage if it is worth the extra expense, my C200K had the odd noise from the front at idle from about 100,000km and we replaced it at about 125,000 by the time I figured what was really the problem.
Ps, when you get to NZ make sure you drive down the South Island through central Otago check out all the hydro dams, beautiful drive.
It runs perfect and dead quite no odd sounding noises.
If you want to replace only the pulley it is quite easy just need to pop the black cap of the pulley and check the p/n of the original pulley mine was INA 535 0165 10 which is on ebay then I brought the two tools required from aliexpres and my 17year old daughter swapped it in over under my tuition.
Replacing the alternator has its merit depending on milage if it is worth the extra expense, my C200K had the odd noise from the front at idle from about 100,000km and we replaced it at about 125,000 by the time I figured what was really the problem.
Ps, when you get to NZ make sure you drive down the South Island through central Otago check out all the hydro dams, beautiful drive.
It runs perfect and dead quite no odd sounding noises.
Last edited by NZ-Merc; Mar 8, 2021 at 12:50 AM.
Super Member
Joined: Nov 2008
Posts: 604
Likes: 29
From: SA
2008 C350-Sport-AMG-Active Agility Pack(Not reliable) +Izuzu KB6 3L(It seems Reliable)+Mazda
Can somebody clarify if all models W204 has this alternator clutch pully. I remember something about my model C350 2008 just have a straight pulley on alternator-??
Last edited by Moto_Guzzi; Mar 10, 2021 at 11:40 AM.
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Have a look at the pulley if there is a black plastic cap over the end then it is a clutch design, if you see (no plastic cover) a nut then it is conventional solid pulley.
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Update: SOLVED
So after a lot of searching I discovered that my Model’s alternator is just a fixed shaft pulley so it wasn’t that. This apparently a common thing though on other engines. Turns out I had the wrong belt. There are 2 sizes depending on your VIN# and when it was built. Not just the year but the actually month of manufacture. One is 2404mm and the other is 2390mm. My car takes the smaller one but I originally bought the larger one. With the new belt all noise stopped. 14mm made all the difference. Luckily it got me under the hood and I found some things that were already wearing and replaced them. Water pump pulley had play in it and a noisy bearing so I replaced that as well. I appreciate everyone’s replies.
Thread Starter
Newbie
Joined: Oct 2015
Posts: 10
Likes: 3
2011 C300 Sport 4Matic
Mileage
I’m at 112k miles. I didn’t have any issues with temp or anything just noticed the pulley had a bit of play and some noise so it may’ve lasted a bit longer but the part is fairly cheap so I went ahead and did it. Besides what I’ve listed here, haven’t had any other major issues. The most expensive was the steering wheel lock breaking. Had to go to the dealer, came out €700.
Super Member
Joined: Nov 2008
Posts: 604
Likes: 29
From: SA
2008 C350-Sport-AMG-Active Agility Pack(Not reliable) +Izuzu KB6 3L(It seems Reliable)+Mazda
Thanks for sharing the lenght issue, I will have to recheck my belt I replaced from dealer with VIN number, I should have the correct one, but who knows untill verified.
Junior Member
Joined: Oct 2020
Posts: 31
Likes: 3
From: Central FL
C300 sport 4matic
Emanual
