E63 whine at high revs

[Rich764089]

Been out for a spirited drive and concerned about a fairly high pitched whine from my E63 S212 above about 4.5k revs. The noise rises in pitch with revs, happens in 1st, 2nd and 3rd gears (can't test beyond this on the road), and is apparent with no throttle, e.g. changing down gears whilst coasting. I can't recreate the noise revving the engine in neutral at a standstill.

Any thoughts on this would be appreciated.

Cheers.

 

[Rich764089]

Is sounds very similar to supercharger whine and is coming from the engine bay (I think).

 

[Bobby Dazzler]

Which engine is it?

 

[Rich764089]

M157.

 

[AMGeed]

Could it be the turbos spooling up?

The pulleys would be the first thing I'd check.

 

[Bobby Dazzler]

Could it be the turbos spooling up?

The pulleys would be the first thing I'd check.

I agree, the two things I would think of first on the M157. Had it been the M156 then it could be top end wear.

 

[Rich764089]

Thanks guys. It wouldn't be the turbos spooling if the noise happens with no throttle would it?

It does sound like a pulley noise...

 

[Bobby Dazzler]

Thanks guys. It wouldn't be the turbos spooling if the noise happens with no throttle would it?

It does sound like a pulley noise...

Best get them checked

 

[Steve84N]

Most likely low gearbox oil. I had the same noise on my S204 C63, even after changing all the pulleys and the belt. Went away after I had a gearbox oil change by happy coincidence.

 

[Rich764089]

Best get them checked

Yes, I'll get it booked in ASAP, probably next week now.

Is this a common problem on the M157? I would have thought the noise would still be present when revving in neutral though?

Pretty annoying as I've only had the car a few weeks. Although it's under warranty, I'm minded to get the dealer to sort it. Failing that, I hope it's not a costly fix!

 

[Rich764089]

Most likely low gearbox oil. I had the same noise on my S204 C63, even after changing all the pulleys and the belt. Went away after I had a gearbox oil change by happy coincidence.

Interesting. I had wondered about this, given there's no noise when revving in neutral. My gearbox oil was done at 30k miles and now on 46k so should be fine, but will get it booked in anyway.

 

[Rich764089]

Just thought I'd update on this, as I took the car into the garage this morning (an independent Mercedes specialist). The owner came out to listen to the car, and although heard the noise, doesn't think there is anything wrong, or that anything needs fixing.

So I am being paranoid about this? Is this kind of noise normal at high revs? It isn't particularly loud, but still doesn't seem right, and happens with/without throttle at high revs. Has anyone else noticed this noise?

The dealer I bought from will pay for anything that's required, so I'm keen to get it fixed if there's something wrong!

I'm thinking I might get a second opinion.....

 

[AMGeed]

I must admit I don't hear any noises at higher revs with my M157 engine. Without hearing yours its hard to make any kind of guess, but pulleys and belts are the main suspect I would have thought.
Did you take it to Alex Crow in Stowmarket? He is a recommended indy in that area.

 

[Rich764089]

I must admit I don't hear any noises at higher revs with my M157 engine. Without hearing yours its hard to make any kind of guess, but pulleys and belts are the main suspect I would have thought.
Did you take it to Alex Crow in Stowmarket? He is a recommended indy in that area.

Thanks. I figured not or someone on the forum probably would have mentioned it...

I've actually just moved to south lincs, but have the car booked in at TWG in Peterborough next week. Recommended by another forum member.

 

[Steve84N]

A supercharger type whine is only normal at high revs if you have a supercharger. As it's also off throttle I maintain that it's most likely slightly low gearbox oil. They can weep a bit and that's all it takes.

 

[Rich764089]

A supercharger type whine is only normal at high revs if you have a supercharger. As it's also off throttle I maintain that it's most likely slightly low gearbox oil. They can weep a bit and that's all it takes.

Yes, I've had a couple of supercharged engines but wasn't expecting it from the M157!

Thanks, Steve, I'm inclined to agree as the noise is apparent off throttle, as you say. I'll be getting a gearbox oil and filter change in the next week or two anyway, so fingers crossed. Just a bit surprised the mechanic thought it normal.

 

[st13phil]

Just a bit surprised the mechanic thought it normal.

Not being funny, but the M157 engine isn’t exactly commonplace, so unless the mechanic is truly familiar with them I wouldn’t put any credence in a “it’s normal” diagnosis.

FWIW, neither of mine exhibited any kind of “supercharger“ whine, so I’d say there is something unusual causing it, but whether that something is anything critical or not is another matter. From your description it’s engine speed dependent rather than road speed dependent, so that automatically points to the source being internal to the engine (unlikely), gearbox input side (possible, as noted by @Steve84N), or it’s an engine ancillary - which is normally where I’d put my money, but puzzlingly you say it can’t be reproduced by revving the engine in neutral which tends to rule that out.

My experience of the M157 is that it’s not a quiet engine, mechanically. It’s actually rather clattery which is a bit unnerving at first as the noises it makes conjure up all sorts of imagined pending failure scenarios. I’ve never noticed one whine though.

 

[Steve84N]

Good point about it being engine rather than road speed dependent @st13phil. I queried with Mercedes whether it could be the alternator as I've replaced the other pulleys and the tensioner. They didn't think it would make such a noise if it was going bad.

 

[st13phil]

I queried with Mercedes whether it could be the alternator as I've replaced the other pulleys and the tensioner. They didn't think it would make such a noise if it was going bad.

There’s also the aircon compressor to consider. If you have a stethoscope, or even a long screwdriver with your ear to the handle, you can touch it on any suspect components and hear if there's a bearing ”singing”.

 

[Rich764089]

Not being funny, but the M157 engine isn’t exactly commonplace, so unless the mechanic is truly familiar with them I wouldn’t put any credence in a “it’s normal” diagnosis.

FWIW, neither of mine exhibited any kind of “supercharger“ whine, so I’d say there is something unusual causing it, but whether that something is anything critical or not is another matter. From your description it’s engine speed dependent rather than road speed dependent, so that automatically points to the source being internal to the engine (unlikely), gearbox input side (possible, as noted by @Steve84N), or it’s an engine ancillary - which is normally where I’d put my money, but puzzlingly you say it can’t be reproduced by revving the engine in neutral which tends to rule that out.

My experience of the M157 is that it’s not a quiet engine, mechanically. It’s actually rather clattery which is a bit unnerving at first as the noises it makes conjure up all sorts of imagined pending failure scenarios. I’ve never noticed one whine though.

No, fair point. The mechanic admitted he was more familiar with the 6.2 and 4.0tt AMG engines.

Yes, definitely engine speed-dependent. Re. revving in neutral - I didn't realise the engine had a limiter (5k?) in neutral that I can't seem to rev beyond. Given the noise doesn't appear until maybe 4,750rpm, I guess I can't categorically rule out the noise in neutral...but I'm reasonably sure.

It is a fairly noisy engine, but this is fairly distinct from the usual clattery sounds!