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I have some engine noise I was hoping you may be able to help diagnose!
There is an engine noise between idle and ~2500rpm. The noise may in fact always be there, however it is hard to pick up above 2500 rpm due to normal engine noise and road noise etc.
The noise is a “whining” sound...It sounds like a pulley to me...however I’m no mechanic!
My mechanic was suspicious that it was the aircon compressor....I have now replaced the compressor, TX valve and receiver dryer as part of an aircon birthday...the aircon works great now, however unfortunately...the noise is still there!
My dad (an ex. BMW Technician) was suspicious of it being gearbox noise...I had the gearbox power flushed and the oil replaced, however again, it didn’t change the noise.
Suggestions that it might have been the gearbox was because the pitch of the noise changes with engine revs, that is, it goes up and down depending on rpm.
I can’t pinpoint the noise with the engine running and bonnet open...it is really only noticeable when driving.
Appreciate any feedback or experiences from other ML owners.
Please, the first thing you must do is update your profile to include the year, model, is it gas, CDI or Blue and where you live, which tells us you have right or left hand drive
So unfortunately I’ve not got to the bottom of this, even after spending quite a lot of money at the shop(s).
A local mechanic replaced the belt, tensioner and idler pulleys...but to no prevail.
Following that there was a “canary” under the bonnet....MB then said that the previous mechanic has stripped the idler pulley bolt thread.
This cost me a lot because they had to replace the water pump to fix that pulley bolt issue.
The noise is still there unfortunately and any further ideas are appreciated.
Just to clarify....the noise comes on and off with the AC respectively.
The noise changes pitch with engine revs....the aircon compressor and thermal expansion valve have been replaced.
I was suspicious of the AC blower, however struggle to be convinced because of the changing pitch..
Remove the left side cover below the Inst. Panel . Turn on the A/C and with the stethoscope, see if there is noise on the blower motor. If not, then you will need someone else to drive and you listen.
If the noise occurs, then remove the blower elec. connector and see what happens.
E Coupe C207, ML W166, ML W164, Sprinter 1500/144, W111 SB220 Fintail(s), A5 chassis Beetle 5+5
Yeah, there's a lot of rotating and reciprocating parts under the hood. Not so much a sound specific to the engine proper. Sounds like AC issues. I would see a pro about it. Usually a BOSCH Service Center is a good start. You can judge a European shop by observing how nice the cars are, and how quickly they turn back over to the owners.
I believe it should be updated now.
It is a 2010 ML 350 4MATIC (W164), PETROL RHD (Western Australia).
Has ~140,000kms on it.
Any more details that will help, please let me know.
Thanks,
Grant
So I am having this same issue I believe, same model year as well. This was supposed to be just a weekend car for traveling to my parents and in laws with the baby but have driving it more recently since my 18 530e is awaiting a registration transfer. It's this annoying whining sound that kind of comes and goes, and only started to come up recently. I'm going to take it to my mechanic who works on european cars specifically and see what he says. I'm in the US so not sure if will be a one for one solution but worth a shot! It has gotten cold here recently in NJ so not sure if it is related to the weather...
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