*STOCK C32 / M112K owners: Check your OE Idler pulley!!!*
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From: murfreesboro,tn
2003 porsche 996 turbo
i had 3 pulleys with imminent bearing failure so for the cost of 100$ or so replaced the pulleys now have the peace of mind that my system is good for a few yrs!
anyone who tinkers with their car should drop the belt and inspect all the pulleys. its easy and can save you thousands of dollars down the road
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From: murfreesboro,tn
2003 porsche 996 turbo
the first was 10$ the c3 450$ and (also new bearing for the oem s/c pulley just to have a spare 56$) and the idler pulley 56$. only the s/c has just a bearing replacement. the others just replace the pulleys with new ones
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From: murfreesboro,tn
2003 porsche 996 turbo
not sure of the answer but i reply with this. i spent less than 200$ on bearings and if it saves me from lunching my 7000$ s/c or 350$ water pump or keeps a pulley from ping ponging around my engine compartment crashing thru my hood ill say it was good insurance
Newbie
Joined: Sep 2008
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C32 AMG
This really is a great thread.
How noisy should the supercharger be at idle?
I have replaced the s/c pulley bearing and the old bearing was definitely well worn. No problem with the idler pulley.
When I was using the stethoscope I noticed quite a racket coming from the front of the supercharger unit, it is also audible to the naked ear. However I can hear the same noise on the video clip in the original post.
How noisy are your superchargers at idle???
How noisy should the supercharger be at idle?
I have replaced the s/c pulley bearing and the old bearing was definitely well worn. No problem with the idler pulley.
When I was using the stethoscope I noticed quite a racket coming from the front of the supercharger unit, it is also audible to the naked ear. However I can hear the same noise on the video clip in the original post.
How noisy are your superchargers at idle???
Senior Member
Joined: Dec 2008
Posts: 343
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From: Taipei, Taiwan
C32 '02
mine is relatively quite for now. will post a before and after code3 pulley clip when i receive it..
I did have my sc bearing changed 5000mi back. i also changed all three pulleys #6,#4,#9. ( #4 & #9 use both the same new part as detailed by the OP )
I did have my sc bearing changed 5000mi back. i also changed all three pulleys #6,#4,#9. ( #4 & #9 use both the same new part as detailed by the OP )
Last edited by ML500K; Oct 10, 2009 at 09:14 PM.
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02 C32 AMG
not sure if this has been covered in this thread, BUT
my LET middler idler with the upgraded bearing failed after 6 months. just be weary for excessive and unusual noises emanating from the engine bay.
my LET middler idler with the upgraded bearing failed after 6 months. just be weary for excessive and unusual noises emanating from the engine bay.
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Joined: Jun 2007
Posts: 58
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From: AZ
C32 '02 silver 70K
In light of recent thread activity on the forum, here is a rather lengthy write-up of a recent experience with my OE idler pulley. Also included is a write-up of the installation for a new idler pulley.
For those who don’t want to read the whole thing, scroll to the conclusions section.
Background:
Case: I have a 2002 C32 AMG with 76K miles. No over- / under-driven pulleys. The poly V belt and all pulleys are in good shape esthetically, and there is minimal rotational wobble in any of the pulleys at idle. I have never removed any of the pulleys and the vehicle’s records (VMI) are also clear of any pulley work.
Introduction: I noticed a ‘louder’ sound coming from the engine bay at start-up one recent morning. Like many of my dealership experiences, I could never reproduce it to grab some video! Aside from the 5 minutes of weird whine, I never heard it again. I initially dismissed the sound as ‘normal’ due to the passage of cooler and better air through the intakes and supercharger. The evidence that partially led to its identification was the fact that it got louder with increasing engine revs.
Hypothesis:
My POS idler pulley is transmuting into a potentially catastrophic projectile.
Materials and Methods:
Stethoscope / tubing, mechanic’s gloves, Torx sockets sized E10 and E12, 15mm socket and wrench, torque wrench (15 ft.lb / 180 in.lb), credit card, and ½ beer (job didn’t take long enough for a full one!).
First, let’s alleviate any confusion by first identifying the pulley in question:
It is pulley #4 in the diagram below. This pulley is also known to MB aficionados/techs as a ‘Tightening’ pulley. It’s the same thing.
Checking for abnormal pulley sounds: Obviously I visually checked and put my ear up against all the pulleys; however, I wasn’t able to hear anything of note. That’s where the stethoscope / piece of rubber tubing is of use. With the engine running, place the piece of tubing very close to the pulley and you will be able to hear any abnormal sounds (please be careful doing this!). For my idler pulley, there was a nasty raspy sound coming from the pulley – most likely an early bearing problem.
Removing the idler pulley: This takes less than 5 minutes (seriously). For those of you not familiar with the procedure, check out the lame video I made of the various steps. Note that you don’t have to remove the upper SC guide pulley, but I wanted to remove it so I could check its integrity and it helps to have it out of the way.
1. Make sure the engine is OFF and preferably not hot! Some people may find it prudent to disconnect the ground on their battery and / or unplug your radiator fan.
2. Remove engine cover.
3. Get the air lines/tubes out of your way by pulley away from the engine (firm but gentle) and remove the torx-head fasteners (2 x E10 torx). Push the air lines away to the left of the engine. If you think the procedure will take some time, you may want to cover the open ends of the tubes and inlets.
4. Slip the belt off the idler pulley by turning the belt tensioner counter-clockwise (E10 torx). After slipping the belt off, slowly allow the tensioner to spring fully back clockwise.
5. If you are checking the SC guide pulley, remove the black bracket that fastens the pulley and holds the belt in place. Superior (top) fastener is an E10 torx and anterior (facing the engine) is E12 torx. The SC guide pulley comes off with the assembly.
6. Remove the idler pulley using a 15mm socket wrench.
7. Reinstall in the reverse order starting with the idler pulley. Use a new bolt and tighten this bolt to a maximum of 15 ft.lb (180 in.lb). Use Locktite if you feel it needs a little more holding power!
8. Obviously an extremely important step when reinstalling the belt is to make sure it is in the correct orientation and that it is aligned exactly with the grooves on the pulleys. You will experience a big truck-load of FAIL if you do not do this.
Here’s a low-quality video showing the various steps.
Results:
Importantly, there was no tell-tale screeching of the pulley. It was just a slightly higher pitch whine/drone than the motor sounds and it lasted for 5 minutes. I eventually identified the source using my stethoscope. There was a nice normal whine coming from all pulleys except one. A nasty raspy whine coming from the idler pulley (#4) – again, through the stethoscope (it wasn’t otherwise audible).
On my car, the OE part number is 112 202 00 19. This part has been replaced by part number 112 202 01 19. The pulley was $72 and included a new bolt and cap.
My old idler pulley (112 202 00 19) has a bearing from NTN. The bearing type is 6303 LHA (and the color is yellow). The bearing in the new idler pulley is 6303 RDD (C3 5C OR5) (color is green).
Here’s a composite of the new and old idler pulleys:
Visual test: no abnormalities could be seen superficially. The bearing seal was intact and I couldn’t see any bulging / deformities or grease.
Spin test: deplorable! As you can see from the video, this pulley is not a happy camper and is not spinning freely. Clearly the bearings are failing (for comparison, compare the video of the new idler pulley rotating). That finding was definitely sufficient for me to get a new pulley.
Here is a video showing the old and new idler pulleys spinning:
Torque value for tightening the idler pulley bolt: 14-15 ft.lb. I got this value straight from the techs at my MBZ dealership.
This torque value is extremely important because stress is placed on the bearing if you over torque this bolt. Increased stress ultimately means decreased life of the bearing. Since this torque value is relatively low, I used Locktite on the bolts for extra peace of mind.
Conclusions:
Your STOCK idler pulley bearings may be failing – even if you don’t hear or see any problems right now! Note that you don’t need any power-adding modifications for your stock idler pulley to fail!
For the sake of 15 minutes, if you have a higher mileage M112K, I think it is worth it to check your idler pulley (and others) to make sure they are structurally and functionally sound. To do this, you need to have a stethoscope (or length of hosing) to amplify the sound coming from the pulley.
While you’re at it (especially you guys who have changed your pulleys in order to accommodate a larger crank pulley), check for play in the belt. If the belt is off, lateral forces can definitely contribute to the failure of the bearing. It’s simple physics.
Even though I heard an abnormal pulley bearing sound for about 5 minutes, I’m sure the bearings on the pulley would start to make much more noise when it is getting closer to complete failure. We may be playing with fire if we want to wait for audible confirmation that our idler bearings have failed.
If I have omitted any important details, let me know so that noobs aren’t led astray.
For those who don’t want to read the whole thing, scroll to the conclusions section.
Background:
Case: I have a 2002 C32 AMG with 76K miles. No over- / under-driven pulleys. The poly V belt and all pulleys are in good shape esthetically, and there is minimal rotational wobble in any of the pulleys at idle. I have never removed any of the pulleys and the vehicle’s records (VMI) are also clear of any pulley work.
Introduction: I noticed a ‘louder’ sound coming from the engine bay at start-up one recent morning. Like many of my dealership experiences, I could never reproduce it to grab some video! Aside from the 5 minutes of weird whine, I never heard it again. I initially dismissed the sound as ‘normal’ due to the passage of cooler and better air through the intakes and supercharger. The evidence that partially led to its identification was the fact that it got louder with increasing engine revs.
Hypothesis:
My POS idler pulley is transmuting into a potentially catastrophic projectile.
Materials and Methods:
Stethoscope / tubing, mechanic’s gloves, Torx sockets sized E10 and E12, 15mm socket and wrench, torque wrench (15 ft.lb / 180 in.lb), credit card, and ½ beer (job didn’t take long enough for a full one!).
First, let’s alleviate any confusion by first identifying the pulley in question:
It is pulley #4 in the diagram below. This pulley is also known to MB aficionados/techs as a ‘Tightening’ pulley. It’s the same thing.
Checking for abnormal pulley sounds: Obviously I visually checked and put my ear up against all the pulleys; however, I wasn’t able to hear anything of note. That’s where the stethoscope / piece of rubber tubing is of use. With the engine running, place the piece of tubing very close to the pulley and you will be able to hear any abnormal sounds (please be careful doing this!). For my idler pulley, there was a nasty raspy sound coming from the pulley – most likely an early bearing problem.
Removing the idler pulley: This takes less than 5 minutes (seriously). For those of you not familiar with the procedure, check out the lame video I made of the various steps. Note that you don’t have to remove the upper SC guide pulley, but I wanted to remove it so I could check its integrity and it helps to have it out of the way.
1. Make sure the engine is OFF and preferably not hot! Some people may find it prudent to disconnect the ground on their battery and / or unplug your radiator fan.
2. Remove engine cover.
3. Get the air lines/tubes out of your way by pulley away from the engine (firm but gentle) and remove the torx-head fasteners (2 x E10 torx). Push the air lines away to the left of the engine. If you think the procedure will take some time, you may want to cover the open ends of the tubes and inlets.
4. Slip the belt off the idler pulley by turning the belt tensioner counter-clockwise (E10 torx). After slipping the belt off, slowly allow the tensioner to spring fully back clockwise.
5. If you are checking the SC guide pulley, remove the black bracket that fastens the pulley and holds the belt in place. Superior (top) fastener is an E10 torx and anterior (facing the engine) is E12 torx. The SC guide pulley comes off with the assembly.
6. Remove the idler pulley using a 15mm socket wrench.
7. Reinstall in the reverse order starting with the idler pulley. Use a new bolt and tighten this bolt to a maximum of 15 ft.lb (180 in.lb). Use Locktite if you feel it needs a little more holding power!
8. Obviously an extremely important step when reinstalling the belt is to make sure it is in the correct orientation and that it is aligned exactly with the grooves on the pulleys. You will experience a big truck-load of FAIL if you do not do this.
Here’s a low-quality video showing the various steps.
Results:
Importantly, there was no tell-tale screeching of the pulley. It was just a slightly higher pitch whine/drone than the motor sounds and it lasted for 5 minutes. I eventually identified the source using my stethoscope. There was a nice normal whine coming from all pulleys except one. A nasty raspy whine coming from the idler pulley (#4) – again, through the stethoscope (it wasn’t otherwise audible).
On my car, the OE part number is 112 202 00 19. This part has been replaced by part number 112 202 01 19. The pulley was $72 and included a new bolt and cap.
My old idler pulley (112 202 00 19) has a bearing from NTN. The bearing type is 6303 LHA (and the color is yellow). The bearing in the new idler pulley is 6303 RDD (C3 5C OR5) (color is green).
Here’s a composite of the new and old idler pulleys:
Visual test: no abnormalities could be seen superficially. The bearing seal was intact and I couldn’t see any bulging / deformities or grease.
Spin test: deplorable! As you can see from the video, this pulley is not a happy camper and is not spinning freely. Clearly the bearings are failing (for comparison, compare the video of the new idler pulley rotating). That finding was definitely sufficient for me to get a new pulley.
Here is a video showing the old and new idler pulleys spinning:
Torque value for tightening the idler pulley bolt: 14-15 ft.lb. I got this value straight from the techs at my MBZ dealership.
This torque value is extremely important because stress is placed on the bearing if you over torque this bolt. Increased stress ultimately means decreased life of the bearing. Since this torque value is relatively low, I used Locktite on the bolts for extra peace of mind.
Conclusions:
Your STOCK idler pulley bearings may be failing – even if you don’t hear or see any problems right now! Note that you don’t need any power-adding modifications for your stock idler pulley to fail!
For the sake of 15 minutes, if you have a higher mileage M112K, I think it is worth it to check your idler pulley (and others) to make sure they are structurally and functionally sound. To do this, you need to have a stethoscope (or length of hosing) to amplify the sound coming from the pulley.
While you’re at it (especially you guys who have changed your pulleys in order to accommodate a larger crank pulley), check for play in the belt. If the belt is off, lateral forces can definitely contribute to the failure of the bearing. It’s simple physics.
Even though I heard an abnormal pulley bearing sound for about 5 minutes, I’m sure the bearings on the pulley would start to make much more noise when it is getting closer to complete failure. We may be playing with fire if we want to wait for audible confirmation that our idler bearings have failed.
If I have omitted any important details, let me know so that noobs aren’t led astray.
Senior Member
Joined: May 2008
Posts: 340
Likes: 0
From: Indiana
Silver 02 C32 & White 05 CLK500
My car was making some strange squeaky noises from the engine. So, I thought it might be the belt since my STOCK 02 C32 has 72k on it. However, before I ordered the belt, I did some research and found this thread. All of the symptoms I had led me to believe that it was not the belt. I took off the belt and spun by hand the guide pulley (next to the sc pulley) and the one right underneath it, the Idler Pulley. The guide pulley was fine as it was already replaced once. Needless to say, as soon as I spun it, the idler pulley was rattling very badly and when I took it off and shook it, it sounded like there was something loose and rattling in it. I immediately ordered a new idler pulley and put it on my car. Now the engine is much smoother and without any noises. I am dreading thinking of how much money would have to be spent if it seized and broke off from the housing. THANK YOU VERY MUCH BOOHOORAMBLERS for this thread and for saving me a lot of money and I hope others will also benefit from this thread.
Last edited by alkrstev; May 31, 2010 at 02:39 PM.
Member
Joined: Feb 2009
Posts: 146
Likes: 0
From: Nashville, TN
C32 AMG
Clarification please.
Definitely a great write up! Can anyone tell me if there's a sound delay in this video - specifically at 1:50 into the video. I'm having a grinding sound coming from the pulley he points to at 1:55. The audio is stating this is the idler pulley, however, I think it's actually the SC pulley.
I've looked at the diagram but it doesn't identify any of the pulley's as Idler or Supercharger Pulley. The diagram has #5 as the Electromagnetic Clutch which I believe is actually the SC pulley. The Electromagnetic Clutch is behind the SC pulley if I recall correctly.
At any rate... Does anyone know where I can obtain the part without paying high dollar from the stealership?
Thanks!
Last edited by AMG_Freak; Dec 15, 2010 at 07:34 PM.
Thread Starter
Super Member
Joined: Jul 2006
Posts: 925
Likes: 2
From: Maine
Not an AMG :(
Definitely a great write up! Can anyone tell me if there's a sound delay in this video - specifically at 1:50 into the video. I'm having a grinding sound coming from the pulley he points to at 1:55. The audio is stating this is the idler pulley, however, I think it's actually the SC pulley.
In the video link, I am indeed pointing to the SC pulley / clutch at 1:55.
I've looked at the diagram but it doesn't identify any of the pulley's as Idler or Supercharger Pulley. The diagram has #5 as the Electromagnetic Clutch which I believe is actually the SC pulley. The Electromagnetic Clutch is behind the SC pulley if I recall correctly.
#4 is the pulley we refer to as the 'Idler' pulley.
If #5 is where you are hearing the noise, check out this thread - you may only require a simple bearing swap.
If you just need the bearing, NeedsWings offers one for about $55. Here's the link.
Super Moderator Alumni
Joined: May 2006
Posts: 4,539
Likes: 4
From: Southern Cal
a C32 AMG & S-Works Tarmac
...
If #5 is where you are hearing the noise, check out this thread - you may only require a simple bearing swap.
If #5 is where you are hearing the noise, check out this thread - you may only require a simple bearing swap.
I am glad to see that you still post your valuable thoughts and comments here. I have been a bit depressed
since you sold your rig and shoved off to school. I hope all is going well for you.Unfortunately, Code3's old video in that link is dead. I'm about to do that bearing swap myself and could have used that for my change out.
Thread Starter
Super Member
Joined: Jul 2006
Posts: 925
Likes: 2
From: Maine
Not an AMG :(
Hey boohoo.
I am glad to see that you still post your valuable thoughts and comments here. I have been a bit depressed since you sold your rig and shoved off to school. I hope all is going well for you.
Unfortunately, Code3's old video in that link is dead. I'm about to do that bearing swap myself and could have used that for my change out.
I am glad to see that you still post your valuable thoughts and comments here. I have been a bit depressed
since you sold your rig and shoved off to school. I hope all is going well for you.Unfortunately, Code3's old video in that link is dead. I'm about to do that bearing swap myself and could have used that for my change out.
Just checked Code3's thread - pity the video is dead. In any case, the bearing replacement is fairly straightforward as long as you have a vice (if not a press).
Just in case you haven't replaced this bearing before, be very careful removing the clip - it can fly off the ends of the pliers and disappear! Suggest you put some tape over the end of the pulley to catch the clip in case it decides to 'travel'!
Re: getting the old bearing out and the new bearing in, a good bench vice will suffice - just make sure you have a block of wood or something that is a good fit over the diameter of the bearing as you don't want unequal load on either side.
You will probably already know this, but you can make life easier on yourself by using the cold weather to your advantage: put the bearing outside to cool and have the rest of the pulley / clutch at room temperature or warmer. The contraction / expansion (however small it is) will help ever so slightly!
Member
Joined: Feb 2009
Posts: 146
Likes: 0
From: Nashville, TN
C32 AMG
Thanks for the clarification and the link to other information. Sorry to hear about you missing your old ride. Hopefully, my car will sound like it should after I replace the bearings.
Yes - for whatever reason there appears to be some type of glitch with my Photobucket videos: the original doesn't have that audio delay.
In the video link, I am indeed pointing to the SC pulley / clutch at 1:55.
Yes - #5 is the SC pulley / clutch assembly.
#4 is the pulley we refer to as the 'Idler' pulley.
If #5 is where you are hearing the noise, check out this thread - you may only require a simple bearing swap.
If you are looking to replace the entire SC clutch / pulley assembly, you are looking at some serious $$$$.
If you just need the bearing, NeedsWings offers one for about $55. Here's the link.
In the video link, I am indeed pointing to the SC pulley / clutch at 1:55.
Yes - #5 is the SC pulley / clutch assembly.
#4 is the pulley we refer to as the 'Idler' pulley.
If #5 is where you are hearing the noise, check out this thread - you may only require a simple bearing swap.
If you are looking to replace the entire SC clutch / pulley assembly, you are looking at some serious $$$$.
If you just need the bearing, NeedsWings offers one for about $55. Here's the link.
Super Moderator Alumni
Joined: May 2006
Posts: 4,539
Likes: 4
From: Southern Cal
a C32 AMG & S-Works Tarmac
Hey Scott! Yes - school is going well. I miss my C32 terribly
Just checked Code3's thread - pity the video is dead. In any case, the bearing replacement is fairly straightforward as long as you have a vice (if not a press).
Just in case you haven't replaced this bearing before, be very careful removing the clip - it can fly off the ends of the pliers and disappear! Suggest you put some tape over the end of the pulley to catch the clip in case it decides to 'travel'!
Re: getting the old bearing out and the new bearing in, a good bench vice will suffice - just make sure you have a block of wood or something that is a good fit over the diameter of the bearing as you don't want unequal load on either side.
You will probably already know this, but you can make life easier on yourself by using the cold weather to your advantage: put the bearing outside to cool and have the rest of the pulley / clutch at room temperature or warmer. The contraction / expansion (however small it is) will help ever so slightly!
Just checked Code3's thread - pity the video is dead. In any case, the bearing replacement is fairly straightforward as long as you have a vice (if not a press).
Just in case you haven't replaced this bearing before, be very careful removing the clip - it can fly off the ends of the pliers and disappear! Suggest you put some tape over the end of the pulley to catch the clip in case it decides to 'travel'!
Re: getting the old bearing out and the new bearing in, a good bench vice will suffice - just make sure you have a block of wood or something that is a good fit over the diameter of the bearing as you don't want unequal load on either side.
You will probably already know this, but you can make life easier on yourself by using the cold weather to your advantage: put the bearing outside to cool and have the rest of the pulley / clutch at room temperature or warmer. The contraction / expansion (however small it is) will help ever so slightly!
Member
Joined: Feb 2009
Posts: 146
Likes: 0
From: Nashville, TN
C32 AMG
I think it may have something to do with Rambler's photobucket account. The video is working in my post on 12/15 @ 6:28pm
Here's the other one:
Here's the other one:
Last edited by AMG_Freak; Dec 16, 2010 at 04:05 PM.
Member
Joined: Feb 2009
Posts: 146
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From: Nashville, TN
C32 AMG
Here's the direct link:
http://s265.photobucket.com/albums/i...rSpin_0001.mp4
I know it works - I'm watching right now.
Member
Joined: Feb 2008
Posts: 242
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E63 W211 08, C32 W203 02
Not sure why the video above is not working correctly.
Here's the direct link:
http://s265.photobucket.com/albums/i...rSpin_0001.mp4
I know it works - I'm watching right now.
Here's the direct link:
http://s265.photobucket.com/albums/i...rSpin_0001.mp4
I know it works - I'm watching right now.
I understand that Pulley 4&9 is the same part 112 202 01 19.
What about the part number for #6?
The pulley #4 is 15lb torque, What about the #6 and #9? is it that same as well?
Thx in advance
Thread Starter
Super Member
Joined: Jul 2006
Posts: 925
Likes: 2
From: Maine
Not an AMG :(
The part number for #6 is 1202000470.
Bear in mind that although the tensioner (#9) and guide / idler (#4) pulley may be similar, the intent is that you replace the entire tensioner assembly (for obvious reasons).
The part number for the tensioner assembly + pulley is 1122001070.
Note that a torque value is not given for the tensioner pulley (#9), because (again), the intent is for the entire tensioner unit to be replaced.
IMPORTANT: Due to the low torque values involved, please ensure that you use Loctite (or the equivalent) thread locker.
