2013 C200 engine/trans drone

[lynall]

Not posted on here for ages as sold Mercs some years back, over the years we had about 6 of them.

Now I am after some advice regarding mates C200 which he says is making a droning noise at certain speeds/load, I thought it must be bloody loud as he is as deaf as a post, so off we go for a spin, bugger me my 1993 defender is quieter!
Is is hard to hold a conversation at pretty much any road speed if you are asking the car for more power.

From the drivers seat the noise appears to be coming from under your left leg, and is especiily noticeable at 50mph on your way to 70, as soon as you go into cruise it quietens down to a sort of acceptable level.
From the passenger seat it is not as bad, but it is still very noticeable.
It is even noticably noisy at town speeds.
If this was a test drove to buy the car I would have driven 500 yards and taken it back and walked away.

I first got involved as the engine was getitng hot new stat sorted that, now the engine oil level appears to be rising, I took one litre out today and told him to just drive it until the dash says to check oil level, then we will know if its fuel related or if his local garage just stuck in to much oil on service.

Anyway sorry to ramble!

 

[W1ghty]

Rear differential ?

 

[lynall]

Bit more googling suggested rear gearbox mount duff, not fully convinced myself but we ordered a new one anyway, upon removing the old one to see it had collapsed so was providing no damping at all, new one fitted and it is like a different car to drive, easy to change did it on the flat.

Also changed fan belt and tensioner plus idlers as belt was skipping across the width of the pulley, that is all goood now.

Next problem! is the engine oil is rising, I sucked out approx 1 litre down to the max mark, and a few weeks later it has risen again, I cannot smell diesel on the oil, but my sense of small aint the best!
There is also engine oil visible between the injectors, oil is dirty is so suspect leaking rocker gasket, not worried about that just more concerned with the rising oil level.
Google seems to suggest injectors could be at fault?

Car mainly does motorway work.