Sudden noise at 60mph

[Robtomo]

Hi all, hope someone can help, I have a 2011 w212, OM651 engine, when driving all is great until I accelerate to 60mph and above. All of a sudden a noise comes on, the only way I can describe it is a loud clicking coming from the front somewhere, if I ease off the accelerator and drop me speed a little the noise completely dissapears. Can anyone please help

 

[dry run]

Sorry I can't help but for me that sound is usually the wife tutting because I'm goint too fast.

 

[Robtomo]

If anyone can help I have been testing what changes the noise, it is purely speed dependant, no matter what gear of engine load it starts at 60 - 65 and doesn't stop the faster I go, could this be a wheel bearing or prop bearing? Driving me mad now

 

[Mr Greedy]

Once the tapping starts, is the tapping also speed dependent e.g. does it tap quicker at 70mph vs 60mph?

And if you had to guess what area it was coming from, would it be front, middle, rear of car, left,.centre or right?

 

[Robtomo]

Once the tapping starts, is the tapping also speed dependent e.g. does it tap quicker at 70mph vs 60mph?

And if you had to guess what area it was coming from, would it be front, middle, rear of car, left,.centre or right?

Yes once it starts it does get quicker when I increase speed, it sounds to me like it is from behind the engine but low down, although hard to tell

 

[Mr Greedy]

I wonder if it could be driveshaft related?
Have you had any gearbox or driveshaft work completed recently?
What mileage is the car?
How many miles have you had the tapping for please?

The bearings/bushings/rubber couplers on the driveshafts (generally) can wear, and I could imagine that because it is directly linked to wheel speed, when there is sufficiently high load due to the rotational speed any play/slop starts to show itself above 60mph.
There have been a few hard-to-trace driveshaft issues on the forums where initial investigations and replacements of wheel bearings proved no use, so driveshaft is a possible contender.
It doesn't sound like wheel bearing to me, which would traditionally be a rumbling, and is a very easy initial check with the car on a post lift. That wouldn't 100% rule out wheel bearing, but it would I think detect and obviously worn one.
Sorry I can't be much more help, other than take it to a well-regarded and experienced Merc specialist in your area to have a look.

 

[Robtomo]

I wonder if it could be driveshaft related?
Have you had any gearbox or driveshaft work completed recently?
What mileage is the car?
How many miles have you had the tapping for please?

The bearings/bushings/rubber couplers on the driveshafts (generally) can wear, and I could imagine that because it is directly linked to wheel speed, when there is sufficiently high load due to the rotational speed any play/slop starts to show itself above 60mph.
There have been a few hard-to-trace driveshaft issues on the forums where initial investigations and replacements of wheel bearings proved no use, so driveshaft is a possible contender.
It doesn't sound like wheel bearing to me, which would traditionally be a rumbling, and is a very easy initial check with the car on a post lift. That wouldn't 100% rule out wheel bearing, but it would I think detect and obviously worn one.
Sorry I can't be much more help, other than take it to a well-regarded and experienced Merc specialist in your area to have a look.

Sorry for the lack of info, first time using a forum, it's done 78000, I have to agree and should have said I have had the wheel bearings check and all was good, I have used my merc specialist and they were useless, I will visit the garage again and see if I can focus there attention to the drive shaft, appreciate your time

 

[alexanderfoti]

Are all the undertrays bolted on securely with ALL the screws present?