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Hang in there. You will eventually figure this out. These are VERY well engineered cars. It will reward you accordingly.
Now, to continue, do you mean you only hear a sound that sounds "like" the fan hitting the shroud? Have you verified that it is in fact hitting the shroud?
Hang in there. You will eventually figure this out. These are VERY well engineered cars. It will reward you accordingly.
Now, to continue, do you mean you only hear a sound that sounds "like" the fan hitting the shroud? Have you verified that it is in fact hitting the shroud?
I should have taken a photo. There is indentations on the fins of the radiator where the fan clearly has contacted the radiator. Now it is unclear to me if these are recent (since my motor mounts were replaced) or from before, but I am inclined to believe the indentations may have occurred after I installed the motor mounts. I am thinking of temporarily taping a piece of paper over the back to the radiator and driving around to see if the paper has indentations/scratches on it from the fan blades. If it is indeed the fan blades contacting the radiator, it appears to only be the tip of the blades, since it has not been enough to do any damage to the blades or radiator (thankfully).
Additionally, I mispoke in my prior thread, I still have not re-installed the shroud. So this would the sound of the fan blades contacting the radiator. It is the only thing I can think of that would make a "clacka-clacka-clacka" noise in rapid succession upon braking (
It sounds to me like a flapping/rattle, not interference. I don't think the fan hitting would sound like that. I would check heat shields underneath.
Around 1:43 the sound is definitely there but your RPM seems to drop but the sound stays the same. This tells me it is not a rotating part as the sound would slow down and speed up with engine RPM.
I agree with you there (about the noise possibly emanating from somewhere else). However, to counteract that theory is that when I removed the fan shroud the rattling significantly decreased - to the point now where as opposed to that consistent rattling, it will only rattle for about 2 seconds and stop, typically when braking quickly. I appreciate your feedback, it is what I am looking for here! If someone points me to the right direction to fix the issue before I take it to the shop I will buy you a six pack!
Okay Schweinhund, you got me thinking about other sources of the noise. I started Googling around. Sure enough, I found a video of another W210 with almost exactly the same noise. The culprit, a bad catalytic converter.
Tonight I may do a little gentle tapping on my cats with a rubber mallet and see if one of them sounds like it has marbles in it. Likely when I get back from vacation I will still take it in for an assessment but I wouldn't be surprised if I have found the culprit.
Yeah I am still going to take it to the shop for a diagnosis/second opinion. No sense in throwing more money at this, especially catalytic converter money, in the event I have overlooked something simple. Will be radio silent for a week or so (out of town) before posting what the mechanic thinks. If its the cats, I'll likely tackle that myself. Found a good DIY on benzworld: http://www.benzworld.org/forums/w210...converter.html
My mechanic claims to have found the source of the noise. He said that the "mounts" on the cooling fan (or aux fan) are broken and so that when the auxiliary fan engages temporarily while driving, it is creating the clicking noise I am hearing. They offer to repair the mounts for $260 using a bolt to reinforce the broken brackets, but I told them I would try to sort it out myself after looking to see that a brand new OEM aux fan is $153 online - and that is assuming I can't find some type of other cheaper solution.
I am going to collect the car later (also got an alignment done), and am going to have the technician show me the area that is broken on the aux fan. I believe it is the long "V" shaped braces at the bottom of part 1 in the assembly shown below. The mounts are part 2.
We will see how easy it is to fix - but at least it wasn't the cats going bad!
I did Google around a bit and did not find this to be prominently written about issue so we will see.
After finding this useful article from Pelican Parts (http://www.pelicanparts.com/techarti...eplacement.htm) it looks like removing the aux fan for repair/replacement, at least on pre-facelift models such as my own, is a very simple task. So hopefully I should be able to tackle this quickly.
Quick update to this thread - I finally had time to dig into the aux fan assembly yesterday. A link to the PelicanParts DIY article on how to remove the fan - which I found very helpful: http://www.pelicanparts.com/techarti...eplacement.htm
So I think something got lost in translation between what the technician at my shop told the service manager, and what the service manager told me. Basically, the mounts in the aux fan were perfectly fine.
What was missing was one of the six plastic pop rivets that hold the aux fan cover to the assembly, and a portion of the fan cover had broken, allowing the thin plastic to slap loosely (and somewhat noisily) against the aux fan assembly.
See this pic of the full fan assembly removed from the vehicle - broken part is at the bottom left (where it appears a chunk is missing - which it is). And the missing pop rivet is in the upper left:
The service manager mentioned something about fixing it with a "bolt" rather than replacing the fan, for $260. Yeah...glad I didn't pay for that. I found a nut/bolt combo in my spare bolt/screw drawer and used it to replace the missing pop-rivet.
While I was in there I took the time to replace my aux fan drive belt (MB part # 011-997-00-92). Glad I did, as the old one, while it still was there, was dried and stretched wayy out, and was no longer properly spinning the non-mechanical fan. The new part (which I bought from PelicanParts) solved that issue and was easy to install following the instructions at the above link.
Basically good as new - only took about an hour to disassemble the fan and re-assemble. I actually haven't taken it on a test drive yet but will report back. Funny how something so simple was the issue - but honestly I would never have pinpointed that.
08-06-2015, 03:43 PM
