I have a Mercedes A Class A170cdi W169 automatic ‘stretched’ 2002 having 120,000 miles on the clock.

For the last three of four years I have had a ‘vibration’ that could be a ‘judder’ at 50mph, 60mph and 70mph very annoying but liveable with if one drives a couple of mph over the affected rev band.

It might have started some four years ago when, whilst in France, we had a very alarming noise that felt as if the gearbox was self destructing, but which cleared before I had chance to stop! So gearbox can’t be ruled out however, the gears all work, change as required and exhibit no adverse symptom! Indeed twice a local gearbox repair specialist has told me that it “won’t be the box”.

Back to the tail, recently two injectors ‘blew out’ the common holding bolt pulled out of the head, for two days after this was repaired there was NO vibration/judder! However it has come back and with a vengeance!

The symptom is that after 5 miles / 6 minutes from cold a vibration – not unlike wheel wobble or even judder – as if an injector is missing, strikes up at revs between 1500 and 2100, corresponding to 30, 40, 50, 60 & 70 mph. It is in any gear, well 3rd, 4th & 5th is most prominent at low acceleration or whilst under light load, often on over-run, down hill, it is absent – but not always. At 50mph +or– an mph or two, the whole car can go through a spasm! The vibration can be felt through the feet, the wheel & ones bottom!
In every other respect the car is perfect, well as perfect as a MB of that era can be!!

So far this is what I have done / propose;
• Had the wheels balanced for the umpteenth time
• Changed the wheels for my wife's A Class (3 years older and also a A170CDI but manual and short wheel base)
• Changed the alternator clutched pulley
• Cleaned the EGR valve and checked its operation
• Replaced the EGR solenoid
• Replaced the pressure sensor to the air filter housing
• Checked the two injectors that 'blew out' both were perfect
• Checked the auto gear box oil level
• Had a gearbox specialist test drive on two occasions (different guys same firm), both declared that the problem wasn't gearbox.
• Had MB test drive but they identified that the drop links were noisy and had no idea what the vibration was - I have since changed the links.
• Have engine mounts on order from GSF - due this afternoon
• Having the whole steering geometry checked this afternoon - it has pulled to the left from new
• Had an independent diesel specialist test drive, he had no idea but thought to start at the drive shafts & work up - not pursuing this until I have changed the engine mounts as it is an open cheque book!

Has anyone any suggestions?

 

This may not help but I recognise your symptoms. Same car 2002 long version. 148K on the clock.
Have had the vibrations for over 60K now, numerous attempts to diagonose, including MB main dealers, but no one has a clue. Scary (gearbox) noise from time to time.. afraid I turn the radio up.
Recently a truly awful noise that sounded like bearing collapse was fixed by my local garage for 3 hours work. Something was rubbing on the drive shaft.

Overall, I've had the car from new and its been pretty reliable. One full set of injectors at 110K is the worst thing to happen.
If you do find out, I'd live to know.
My plan is to run and run until it just wont go anymore.