smoke bursts at 70mph +

I have a V40 T4, all vital signs and performance is excellent. under 70mph all is fine (no smoke) At 70mph + accellerate and I get large clouds of blue smoke, (which is obviously burning oil) this then stops and clears itself can run without any smoke. I have changed the turbo as I thought this was the problem, the oil return pipe was blocked so I presumed that that was the problem. Now it is doing exactly the same with this turbo. compression is ok. have recently had a service, new oil, filters etc. what can be causing it. previous history, original engine was blown with turbo at high speed after being stolen subsequently chucking loads of oil down the exhaust etc.. I replaced engine and turbo, plus much more, have a new cat. but not replaced yet. Can anyone help out what could be causing this, engine runs lovely plenty of power, nice and quiet, doesn't use coolent or run hot, infuriating for people behind me.. cheers Pml.

check your crankcase breather and oil seperator, you might be blowing engne oil through the breather system into the intake, you shuld be able to see it if you strip off the inlet hose, oil on the inside and around the throttle body, for that matter its worth cleaning and clearing the entire breather system and all avac lines... Take a look and lt us know how you get on....

problem Located 

after all of the problems i have described re: the smoke problem, on following my car down the motorway I discovered that my smoke was not coming from the exhaust as thought but oil blowing out directly from a very small hole in an engine blanking cover back end of the block, at high pressure absolutely bellowing out spraying oil on to the exhaust and down the car, only really aparent at high pressure speeds . So ( relief) not the Turbo or the Engine or anything major, which therefore explains the perfect running performance of my car. This will be fixed in the next couple of days. Amazing what a tiny little almost un noticeable oil leak can do.. I will keep you updated.

Glad you got it sorted Paul. Mat

Problem Solved 

Problem solved despite all the speculation of , turbo probs, engine, blockages,,, all along it was a hairline crack in the Turbo oil return pipe, so New pipe and O ring and sorted... I new all along that with it's performance apart from the oil actually leaking and spraying on the cat at high turbo boost, there was nothing wrong ... NOw super fast and not burning oil at all