Blue smoke on idle, back pressure?

[kallabungo]

I've been dealing with this saga now over the last year or so, blue smoke on idle - diagnosed by the garage to be piston rings, thus i went ahead with the work only to find out it was the turbo all along and had to pay for that to be re-conditoned as well!

It was hell but at least the turbo had stopped leaking - 2 weeks later it started again! apparently the lack of back pressure because i have a full 3" bore all the way from the turbo to the back box (powerflow) can cause the seals to let oil leak through.....? Im just wondering how realistic this is.

I've spoken to wannabe mechanics from corner garages up to the people at re-worx and other highly respected companies and have very mixed opinions about the whole thing.

I did wait until the car started smoking on idle (normally about a minute) then stuck a concentric reducer in the tip of the exhaust - just pushed in, and within 5 seconds the smoke stopped. It sounded funny as hell but never the less it stopped the smoke....?

Any opinions on this?

[Welly]

That's a very interesting point.

The exhaust side of the turbo does need an element of back pressure to maintain a seal and is normally less able to maintain an oil seal on tick over. However the size of the tubing shouldn't affect this phenominon in my opinion (just look at most Jap cars).

I do know one thing though which can cause the smoke....a partially blocked oil drain off the turbo. If the oil can't drain away fast enough it builds up and makes it past the seals (this happens on Mitsubishit GTO's).

See what the others have to say........

[jameslxdt]

if you had turbo failure, then the exhaust will be completley full of oil, if your pug dealer did the work, or i did, then it would have had all the pipework, intercooler and exhaust system replaced otherwise you wont get rid of the blue smoke

[mikey s]

alot of the 205 boys suffer this when transplanting the 2.0 turbo into the 205. its due to the seal in the turbo. theres a mod for it that involves changing the seal for a step seal. im sure a search on the net or registering on 205 gti drivers would bring something up on it.