CLS55 Weird Engine Noise (help & video!)

[RetiredSlider]

Hey All,
I wondered if you'd be able to help me shed some light on this. I've owned my CLS55AMG for the last 2 years and it's always ran faultlessly. It has however always had this weird whining/grinding noise coming from the underside of the car towards the rear of the engine.

It happens shortly after start up and goes away once revved. But comes back. It also goes away once it's really warm (or after a long run)

Other than being really annoying, it doesn't seem to affect the drive at all. It also isn't coming from a bearing. It seems to be coming from the back/underside of the engine. I also think it got worse after my last oil change, although i can't be sure.

Anybody got any experience with this?

Video of the noise
https://www.youtube.com/watch?v=8gTvbGyKPo8

Video of it being revved then coming back at the 2:10 seconds point
https://www.youtube.com/watch?v=yz66FymR698

Both taken from underneath the car (it was on the ramp in my garage)

Cheers for your help

Chris

 

[Lenny63]

I may be going mad, but this sounds fine to me...

 

[RetiredSlider]

I may be going mad, but this sounds fine to me...

Do they tend to have noisy oil pumps?

 

[Lenny63]

Not a quiet engine by any means - in fact my friend said mine sounds like a diesel
In a video on idle when filming up close around the engine bay

 

[b1g1an]

Do they tend to have noisy oil pumps?

They do have noisy oil pumps, that's what makes the whine at startup that many think is the supercharger

Some can make it constantly at low revs, particularly after an oil change, but I can't hear that in your vids. If you do get one that wants to be heard it's literally the same as startup but quieter.

 

[b1g1an]

Not a quiet engine by any means - in fact my friend said mine sounds like a diesel
In a video on idle when filming up close around the engine bay

Diesel from the front, boat from the back.

 

[simon1966]

Sounds pretty normal to me. As said they are certainly not quiet engines and pretty much everyone one I've heard sounds like that. I know you didn't ask about the constant clattering tapping noise, but just to add that it isn't the valve lifters as most assume, its the oil pump chain slapping inside the engine casing. Basically they have weak tensioners allowing too much play and the chain merrily goes round inside wearing grooves inside the front engine casing!