Carlssonjj

Hi Everyone. This is my first post. I'm looking for some technical input or similar experiences with solutions.

I had upon until February 2016 a perfectly working 2011 520d M Sport Auto. FBMWSH and in perfect mechanical order. The mileage was approaching 110k but the car was perfect. A work colleague of mine had recently had the dreaded timing chain snap which cost him several thousands to fix his 520d f10. He advised that i got mine done to avoid the same happening. He recommended a garage to me in London, a reputable Bosch approved garage. We agreed the price and I got the timing chain done. This is a biggish job which entails removing the engine. When I got the car back I noticed that when the car engine temperature was warm I would get a smell of oil in the cabin. Driving wise the car was perfect with the exception of this oil smell. I returned the car to the garage where they confirmed that there was an "O" ring leaking, and they repaired it. I picked up the car and headed home up the A1. Straight away I noticed a violent vibration / shuddering in 7th and 8th gear around 2000rpm that was never there before. I called the garage straight away and told them. I brought it back and we went for a road test. The lead mechanic witnessed the vibration and ask me to leave the car with him to see if he could diagnose the issue. I explained that the vibration was not there initially, but only after they attempted to fix the "O" ring leak. When I asked what works were carried out to fix the leak the garage mentioned that they had to remove the injectors and replace seals and a rocker cover gasket. I thought surely it must be a problem with the injectors then?

Anyway the garage had the car for a month trying to diagnose the problem. They balanced the tyres, tried other wheels, tested the air intake system, turbo and said all is ok. I read an online thread with a similar issue and it turned out to be an injector issue. I told the garage this, so they focused on the injectors. They tested all the injectors and said that injector 3 was not performing as well as the others so they replaced it and charged me 460 pounds. This made no difference to the vibration/shuddering. They eventually gave me the car back and said for me to go elsewhere and get advise. (not very helpful). So after spending £2000 to fix a problem that was not there (timing chain) I ended up with a car that I couldn't even sell if i wanted to.

Anyway, I then took the car to an independent BMW specialist in Stevenage where they took the car on a road test. They said it felt like a gearbox issued and recommended a gearbox specialist in Biggleswade. I booked in a road test with them at short notice. They were very helpful. After the road test they were of the opinion it was the torque convertor but asked that i leave the car with them for further tests to be 100% certain. I get a call 4 days later to say that they have done some tests and that they are not 100% sure it is the torque convertor. They have said that in the past it has either been an injector issue or a torque convertor issue.

The ball has been left in my court now with the decision of what to try and fix first. Either way each job will cost a £1000 + VAT each. I really feel hard done by here. Can anyone comment on the following;

- similar issue with a solution/possible solution
- advise on which option to try and fix first - injectors or torque convertor
- advise on any recourse against the original Bosch garage - surly they have a duty of care to sort this issue for me if they have induced it?

Thanking you in advance.

Jonathan