C63 W204 - whine under acceleration

[8bit]

Had the day off today so took the scenic route back from some errands in the morning. Noticed a whining sound, a bit like a supercharger, when under high-ish throttle inputs. Mainly when pulling hard through third and fourth. I checked the engine bay and unfortuately found that I had not installed a supercharger and forgotten about it so it's definitely not that.

I checked the engine oil and the level is between the marks on the dipstick but towards the low end of that. Could that be it? Ot something else?

 

[Bobby Dazzler]

Had the day off today so took the scenic route back from some errands in the morning. Noticed a whining sound, a bit like a supercharger, when under high-ish throttle inputs. Mainly when pulling hard through third and fourth. I checked the engine bay and unfortuately found that I had not installed a supercharger and forgotten about it so it's definitely not that.

I checked the engine oil and the level is between the marks on the dipstick but towards the low end of that. Could that be it? Ot something else?

How are the pulleys, is one (or more) noisy?

 

[8bit]

Not sure, the noise is only present at or close to WOT though so not sure how I'd tell?

 

[PhilT]

Air leak or pcv. Most likely intake manifold gaskets or the manifold itself as they corrode being magnesium.

 

[8bit]

Air leak or pcv. Most likely intake manifold gaskets or the manifold itself as they corrode being magnesium.

Any other tell-tale signs for that? Fault codes I would imagine? Would that only occur under load or would I hear when revving in neutral?

 

[jonboyE63]

My E63 had this supercharger whine a few years ago, a quick transmission service and the whine was gone…not saying this will resolve your issue but it certainly sorted mine….

 

[8bit]

Thanks for that - it's due a transmission service soon anyway so I'll see how it is after that.

 

[Steve84N]

It's not the pulleys, that's a different sound. I had the same supercharger noise, changed the pulleys and no different.

It's low gearbox oil, after a service it'll go away. Oddly, it does come back over time before you'd expect to service it again. Almost like it's using/losing some oil.

 

[PhilT]

Any other tell-tale signs for that? Fault codes I would imagine? Would that only occur under load or would I hear when revving in neutral?

Not always, sometimes the fault is them but with no codes showing.