Grinding noise at low speed - e280CDI

[Nigel55]

Hi

This is my first ever post - new member and all that but I have an issue which is baffling me. My car is a 2009 e280CDI Sport W211 (G7 box). Amazing car in every respect.

I have done 60,000 miles in the car (now at 90,000) and have done all the servicing myself using Mercedes parts. This includes a gearbox oil and filter change at 50,000 miles. (Handy having an inspection pit in your garage).

However, I have a problem which is baffling me big time. At low speed, rolling from a standstill up to about 20mph you can hear a grinding noise (much like a wheel bearing noise but it is fairly quiet). I’m sure it is there at higher speeds but road noise drowns it out. So for those detectives out there here goes with the evidence:
• The sound started in the last two weeks
• The sound can be heard in the car as if it is coming from the centre/rear-centre of the car
• There is no vibration in the gear level (auto gear level)
• The noise is not engine rpm related, in fact it seems to remain constant as speed increases
• Turning the engine off and rolling down a hill at 10mph the sound is still there
• Going from left to right (zig zagging) does not change the sound
• Jacking the rear of the car up, engaging drive and giving her a little gas - the same sound can be heard
• There is little movement in the rear wheels when manually rocked (assume wheel bearings are fine?)
• Spinning the rear wheels by hand when the car is jacked up doesn’t seem to replicate the sound but then I can’t spin the wheels too much – weak arms
• Under the car, there are no signs of oil leaks – she is as clean as a baby

Now I plan to do a gearbox service this weekend. Will this fix it? Unlikely but the car needs it anyway.

So what do you think? Box, diff, drive shaft, wheel bearing???

Great to hear your opinions.

Also if you are a car nut then take a look at my website nigeldean.co.uk under the specialist automotive tab to see a handful of kit cars I have built.

Click on the thumbnails to enlarge the pics

Thanks

 

[whitenemesis]

If it was a W203 I'd say parking brake cable rubbing on the propshaft after one or more clips let go. Does the E have a similar setup?

 

[Nigel55]

Thanks, I will check tomorrow when I'm under the car servicing the gearbox. But very good point - check the obvious first.

I'll check the prop and drive shafts for any obstructions tomorrow morning when I'm servicing the box and report back.

Nigel

 

[a111r]

I'll go for a partially dropped heat shield.

 

[SMS]

Tyre noise, see it so often.

 

[Nigel55]

Thanks SMS - I wish this were the case but the noise was still there when the rear wheels were rotating in the air (car jacked up)


Appreciate the help.

 

[Stratman]

Possibly a stone trapped between a disc and backplate or even embedded in a brake pad, or the small possibility of a parking brake shoe rubbing in the drum.

 

[Nigel55]

Thanks Statman - luv the picture.

Well, gearbox service done today and looked long and hard for anything rubbing on prop or drive shafts - all looks clear. Have yet to check the brakes but again a possibility.

However, my baby is going into the garage tomorrow for new front springs - one broke on Friday. It seems that it just doesn't rain but it pours.

Anyway, I have put up a £20 cash wager for the mechanic at the garage who can identify the grinding culprit first - that should keep their minds focused. OK, they should do it for free but its amazing what a 'drink' will do.

Anyway, I'll update you all soon

 

[Nigel55]

Sorry not Statman - Stratman

As an additional note when I went to my local Mercedes Garage for the gearbox service kit they said I only needed 6 litres of oil - wrong.

In fact you need 9. When I questioned the response the stores man said you do not have to drain the torque converter - we never do. Wrong. The Mercedes work instruction has been updated to say this is part of the service. Once I explained this he went a little quite and said he would have to tell his mechanics. He then started to ask where I got the work instruction... my reply the 'Internet'

The moral of the story is if you get you 7 speed auto box serviced (oil and filter) demand the torque converter is also drained (An addition £45 in oil and a new plug). It always seemed odd to me you would only change half the oil during a service?????

Bye for now

 

[Nigel55]

OK, just to end the story

Garage cannot find the source of the noise. Great. In fact the mechanic said he would not have picked it up if I had not said anything. Well that's how silky smooth Mercs are mate

Suggested diagnosis was wait until it gets a lot worse and then we investigate again.

 

[Nigel55]

I found the problem!!! It was the propshaft centre bearing. Cheap to fix but hours of effort.

However, I decided to sell the car and opt for an upgrade - C63 AMG W204 facelift

What a weapon