turbo gone - what's wrong with it?

dturbo · Post by **dturbo** » 27 Jul 2008, 11:07

massive amounts of white smoke were pouring out of the exhaust of my 306 Dturbo like a steam train, I couldn't see anything out the back and neither could other road users

I though white smoke = water and that it was the head gasket again, there was no loss of boost/power during the smoking

pug said it was oil not water & replaced the turbo - no problems since

I'm looking at the old turbo & it looks ok to me, can one of you technically minded people explain what has happened to it & why?

saabsalltheway! · Post by **saabsalltheway!** » 27 Jul 2008, 14:04

hi
as turbo gets hot and cold so do the rubber seals then they let oil past and into the turbo on intake side it gos through the cylinders and gets burned causing smoke, also on exhaust side leaks out and is burned by hot exhaust gasses causing smoke. quite a common problem cus at some point everyone drives the car hard then parks up leaving the turbo to sit in all that heat and it cooks the oil in it. thats why its a good idea to drive the car at a slower speed for about 10 mins to help the turbo to cool a bit.
to much info i no but you now know what could be the cause of the death of a most loved power unit.
paul

AndersDK · Post by **AndersDK** » 28 Jul 2008, 01:22

Sewing machine oil is used for model train "steam" using a tiny glowplug built into the chimney.
A single drop of oil, and the train is ready for yet another trip round the track.

Same happens in your turbo, when the hot (exhaust) side of the turbo leaks out engine oil into the hot exhaust - from a failing turbo oil seal.
As you have seen this produces clouds of white smoke from evapourating oil.
The oil is not burnt - if so it would produce the wellknown worn engine symptom : lots of bluish smoke.

If the turbo oil seal fails on the cold (intake) side, the oil will be leaked into the intake and burn just like the fuel.
This is fatal for a diesel, as then a cold side failing turbo will cause the engine to run away - race up in revs uncontrolled - as long as there is engine oil left to leak into the engine inlet.
The only method stalling such a run away engine is to strangle the air inlet.
Trying to stall it by selecting high gear may destroy either clutch or g/b.

dturbo · Post by **dturbo** » 28 Jul 2008, 16:42

Thanks guys for the thorough info. So basically it was just a seal gone & pug being incompetent to replace it replaced the whole unit?

As for stalling a runaway away engine would blocking the exhaust with your shoe provide the same result or would the engine suffer?

lolingram · Post by **lolingram** » 28 Jul 2008, 16:53

The only method stalling such a run away engine is to strangle the air inlet.
Trying to stall it by selecting high gear may destroy either clutch or g/b.
_________________
Anders (DK)

I can confirm that stalling a runaway 2.1TD by selecting 5th gear and being quick about it works fine - as long as you are quick and don't dilly-dally.