Power steering noise when cold
03-06-2017, 07:09 AM
#1
Junior Member
Thread Starter
Power steering noise when cold
Good day,
New member without many posts but have been lurking for a while. (Car is a 2012 C350 with the M276 engine and 4Matic) I did a search of the forum to see if anyone had posted a similar complaint. Mine is a bit different than most. This noise only happens on a very cold start (first thing in the morning for example). Upon starting, if (and only if) I move the steering wheel, I will get a slight whine or muted "screech" from the serpentine belt. This only happens when I move the steering wheel (when idling without moving the wheel, the belt is relatively silent). After about 30 seconds to 1 minute (depending on how cold it is outside), the noise is completely gone. I did check the power steering fluid level and it is fine (between the min and max marks, but I did add a little bit of fluid to see if it made a difference, .... it didn't). When I turn the wheel from lock to lock, it is quite smooth with no other noises or "groans" to make me think the steering rack or anything else is the culprit. The power steering pump is quiet as well (once the initial 30 second warm up is over). Because this only happens when starting on a very cold engine (overnight or 6 + hours of sitting), it wouldn't do it for the mechanic, but, he suggested it may be the idler pully /belt combo. Although he did inspect the belt and said it looked good (no cracking or heat shine from wear). I'm hoping it is something simple, like a tensioner or pully and belt. Your thoughts? Thanks in advance!
New member without many posts but have been lurking for a while. (Car is a 2012 C350 with the M276 engine and 4Matic) I did a search of the forum to see if anyone had posted a similar complaint. Mine is a bit different than most. This noise only happens on a very cold start (first thing in the morning for example). Upon starting, if (and only if) I move the steering wheel, I will get a slight whine or muted "screech" from the serpentine belt. This only happens when I move the steering wheel (when idling without moving the wheel, the belt is relatively silent). After about 30 seconds to 1 minute (depending on how cold it is outside), the noise is completely gone. I did check the power steering fluid level and it is fine (between the min and max marks, but I did add a little bit of fluid to see if it made a difference, .... it didn't). When I turn the wheel from lock to lock, it is quite smooth with no other noises or "groans" to make me think the steering rack or anything else is the culprit. The power steering pump is quiet as well (once the initial 30 second warm up is over). Because this only happens when starting on a very cold engine (overnight or 6 + hours of sitting), it wouldn't do it for the mechanic, but, he suggested it may be the idler pully /belt combo. Although he did inspect the belt and said it looked good (no cracking or heat shine from wear). I'm hoping it is something simple, like a tensioner or pully and belt. Your thoughts? Thanks in advance!
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pozi240 (03-06-2017)
03-06-2017, 12:55 PM
#3
Super Member
What's the mileage on your car? It might not directly be your power steering, but if its a belt type noise, it might actually be the belt tensioner that's on its way out
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pozi240 (03-06-2017)
03-06-2017, 01:05 PM
#4
Junior Member
Thread Starter
80k km's (50k miles). It has been very well maintained overall. (I just picked it up recently with 78k km's). All fluids (including the transmission were done just prior to me purchasing). It was bought at a MB dealer (1 owner lease return), but, sadly, no CPO warranty. I'm not convinced the steering rack is on the way out, possibly the pump, but, am hoping for the belt/ tensioner to be the culprit. Also, to add to this (that may tie into your theory Funkwagen, we had a really cold day this past weekend (-23C) and the belt whined a bit even without moving the steering wheel and it quickly got quiet as the engine warmed up (less than a minute or two)....so, could be the tensioner. I'm going to leave my car overnight at the local MB mechanic (independent MB mechanic) and get his take on it when he can actually hear the noise himself. Thanks!
Last edited by pozi240; 03-06-2017 at 01:12 PM. Reason: new details
03-06-2017, 01:45 PM
#5
Junior Member
Thread Starter
When I get a good diagnosis and solution (hopefully in the very near future), I will post what it was so that anyone searching in the future with a similar complaint can see what the problem was. I always appreciate when I see the OP post a final "closure" to the problem.
03-07-2017, 12:46 AM
#6
Super Member
80k km's (50k miles). It has been very well maintained overall. (I just picked it up recently with 78k km's). All fluids (including the transmission were done just prior to me purchasing). It was bought at a MB dealer (1 owner lease return), but, sadly, no CPO warranty. I'm not convinced the steering rack is on the way out, possibly the pump, but, am hoping for the belt/ tensioner to be the culprit. Also, to add to this (that may tie into your theory Funkwagen, we had a really cold day this past weekend (-23C) and the belt whined a bit even without moving the steering wheel and it quickly got quiet as the engine warmed up (less than a minute or two)....so, could be the tensioner. I'm going to leave my car overnight at the local MB mechanic (independent MB mechanic) and get his take on it when he can actually hear the noise himself. Thanks!
Sounds to me like it's more likely to be tensioner, then. I had the same problem, the colder it was outside, the more the belt would squeal or chirp on cold start until it warmed up. As soon as I replaced the tensioner (which hadn't yet completely failed), the issue has been gone
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pozi240 (03-07-2017)
02-04-2022, 07:03 PM
#7
Super Member
When I get a good diagnosis and solution (hopefully in the very near future), I will post what it was so that anyone searching in the future with a similar complaint can see what the problem was. I always appreciate when I see the OP post a final "closure" to the problem.
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wwharrison (11-19-2022)
