bullitt69

Hi everyone,

When I bought my 2011 facelift P30 c63 3 months ago I noticed slight engine speed dependant whine especially noticeable while driving at low speeds in underground parking lots. The frequency of the sound doesn't really change when turning the steering wheel, only when revving the engine.

I was told that it could be low/old power steering fluid and had it replaced. Nothing changed.

After additional research on forums I came to a conclusion that must just be the regular sound of the M156 engine or the sound of the oil pump as I was told at one shop.

Now the story continues.

Periodically when driving over puddles or in heavy rain I get groaning from the left (driver's) side of the engine and vibration which I could feel through the steering wheel and seat. When this groaning happens the sound of the whining mentioned above gets louder as well!!

It seems to occur mostly while maneuvering at low speeds or hitting pot holes. The groaning is engine speed related and I get no CELs! The groaning can disappear as suddenly as it appears which makes it hard to diagnose and demonstrate to the mechanic.

When it happens it sounds as if something is wrong with the engine or gearbox as it is engine speed related, but when I hear the groaning the car's engine works perfectly and the car doesn't lose drive.

This makes me thing that it could be one of the pulleys or accessory components which are driven by the serpentine belt: steering pump for example. But the steering fluid level is ok, the steering wheel doesn't feel heavy and it happens ONLY during rain.

Any ideas or ways how to diagnose this weird problem?

I recently had all 3 engine mounts replaced and also double checked the entire exhaust system whether it's rubbing the bottom of the car.

Video of the whining:

bullitt69

I posted videos of the sound before in this thread:

https://mbworld.org/forums/c63-amg-w...-start-up.html

It seems that the whining substantially increases after driving though deep puddles.

I guess I'll have the power steering pump checked as well as the pulleys around ot

Alex.currie44

I didn't sense anything all that weird on start up but have no clue as to the other issue. The fact that puddles are involved might suggest you try spraying some water around in the area with a hose to see if you can replicate it.

bullitt69

Here is more detailed sound of the whining right after driving on a very wet road:



I will try spraying the pulleys with a hose. Just tried doing it with plant sprayer, but the stream is probably not strong enough as it didn't do a thing.

Merc63

Mine has been whinning doing slow turns etc too. Did you figure it out?

bullitt69

I didn't - no. They took off the serpentine belt and the whining didn't go away. We tried pouring water out of a hose over the pulleys to replicate the sound - the engine began droning a bit at around 1-1.5 K rpms, but no metallic sound like I had before after driving through a puddle.

The mechanic said it was definitely something from inside the engine: we lifted the car up, took off the protective shielding and tried listening with a screwdriver to the ear from beneath the oil pan. No droning - so it's not the oil pump.

Anywas now I experience droning from the engine even in perfectly dry weather going straight, but only when the rpm needle is around 1-1.5 K rpm.

The only fault code I have is the incorrect position of the 2nd bank (driver's side) exhaust camshaft - but that fault code usually means the cam adjuster is on its way out, giving rattling sounds on startups.

I don't have a single clue about my problem and no idea where to dig further. The mechanic said that the engine sounds perfectly good and should just keep enjoying the car.

Alex.currie44

Sounds like good advice. Run it until it breaks.
That said do you have an extended warranty either from MB or a third party? It might be worth getting one. You may have to pay for a pre-insurance inspection and while the premiums in my experience are not cheap keep in mind it doesn't take much. My first claim to replace a leaking AC evaportor was more than 50% of the price of the premium.
Just a thought.

bullitt69

Thank you for the advice! The car is out of warranty and I'm paying for all repairs myself. They have some sort of post warranty support from Mercedes Benz in my country, but I think it covers only part of substantial repairs and you have to apply for something like that (i think it's called "kulanz")

bullitt69

I forgot to mention that when they scanned my car with Xentry the following fault code was stored: P0365 "The output for the actuation of the alternator has a malfunction"

Could it be the bearings in the alternator dying? That really makes sense provided I was getting a grinding noise after reducing in the rain.

Jasonoff

How could it be alternator bearings if it wasn't spinning at the time of the noise?

bullitt69

I know this sounds stupid, but maybe the vibration issue and grinding issue are 2 completely separate things.

The thing is that in the workshop we were only able to replicate the vibration, after pouring water, but not the grinding I've experienced on the street.

When the mechanic pulled the serpentine belt and asked me to start the car, the car ran fine with zero fault codes on the instrument cluster. There was the humming present, but what surprised me is that I was expecting to see a Christmas tree of fault codes, but it just ran fine.

ai.borodin

Any result in solving this problem? I have everything exactly the same with my 2010 C63.

Mully78

This sounds a lot like the issue I'm having. Sorry to bump another old thread, but did anyone ever get this problem solved?