White smoke and full maximum rpm on vauxhall vectra?

hi
I was driving back from holiday and my vectra 2.2 dti dieseil decided it was going to rev itself as hard and high as it can possibly go and a constant cloud of white smoke out of the exhaust.
I pulled over and removed the car key which i was amazed to see and hear that it was not stopping the engine carried on as though i had the accelerator flat to the floor which i didnt.
I was told by the AA guy that it would be the turbo.
I have had the turbo changed by a machanic and he said the pipes still have a little oil in which will still give off smoke. Well travelling at a slow pase it decided to take 2 and do it all over again.
I taken it straight to the garage and he said the intercooler was full of oil so we have cleared that out. It should be fine now with a little smoke.
Well 3rd time lucky 10 mins driving and it decides to do it a 3rd time. OMG.
The only way i can stop this is to slam it in 5th gear and stall it with full brakes on.
Your help would be much appreciated and thankyou very much in advance.
By the way ive left the car dumped on the path outside my house in angar.