Blue smoke out of exhaust
 

I noticed this morning that my car was producing some blue smoke. Not all the time, seemed worse when slowing down with a trailing throttle. When I stopped when I got to work there seemed to be a very little blue smoke coming out of the exhaust at idle.

It's an MY94 WRX wagon with TD05.

The TD05 was serviced by turbo dynamnics about 6 months ago.

I topped up the oil on saturday morning. I hope this is the problem!

Any ideas?

Well thats a starting point. Just have a quick look make sure you havn't over filled the system. The boxer engine just doesn't like to be over full.

Blue smoke is burnt oil. As Rokay says probably an overfill.

hope so. I put 4.25 litres in on last oil change 2 weeks ago as normally do, checked it before making long drive to london on sat and found it to be low (although did not really give much time for oil to settle) so thought better be safe than sorry and put another 500mls in.

I really hope that is it.

Checked the oil and it seems ok.

It only emits blue smoke when the engine is warm, not at start up. Might have to get it checked out as it could be turbo seals or piston rings could it not?

Yeah mate sounds like the same problem i used to have with my 20VT Coupe .Turbo seal has gone with the sounds of it.
Get it checked out as turbo needs to be taken off car and inspected for excessive play on the seal.
It only does it on idle because there is no exhaust pressure to close the seal tight that you get whilst on boost.
As i say get it to a specialist.
Andy

Just had turbo core replace 6 months ago. Maybe I have a warranty! I did have an occasion the other day when I had to turn off the ignition straight after a hard run with no cool down period. Surely a one-off like this cannot cause this problem?

Actually what happened was that I had set the turbo timer for 8 minutes while I nipped into the house to get something (so as to keep engine running) and then when I got back into the car I did not turn the key all the way to the run position. Headed of at a great rate of knots, onto the motorway doing 90, and in the dark, and suddenly the engine stops and lights go out. Bloody scary! I stopped and it took me a while to figure out what was going on - turbo timer had cut the ignition after 8 minutes as it was supposed to. I did notice a bit of a hot smell!

Blue smoke means burnt oil. If the oil is leaking into the exhaust on the turbo it won't be burnt and will come out as white smoke. If it's going into the inlet side then that enters the engine, is burnt and comes out blue.

Not sure if that proves its the turbo or something else - I've seen oil getting into the crankcase breathers and going into the inlet and coming out blue, which was caused by overfilling.

Well I am not 100% sure of whether it's white or blue, thought it had a tinge of blue, but then sometimes I think it doesn't. It is definately not as white as the condensation that comes out normally. I was initially unsure and thought perhaps it was just condensation but it has a burn't oil smell.

It is much worse when the throttle is partly open, a nice smelly trail folloing the car.

Someone is going to look at it tomorrow, so fingers crossed it's nothing too major.

Good luck !!

wouldn't have thought it was piston rings or you should get blue smoke all the time,valve seals can cause blue smoke on start up and overun as this is when the inlet is at its biggest depression so it sucks the oil through then you put your foot down and the pressure increases so it stops sucking the oil through.don't be frightened tho as i haven't heard of these going on a subaru its probably something much more simple.

Cheers mate, nice consoling words, lets hope so.

its burnt oil, but i ccant remember if its rings (in general) for overun , or the oil control ring for overun..

the other one is front crank oil seal..

that throws a few oddities into the pack

M

Seems that turbo seals most likely, oil dripping into exhaust and burning there. Good news though, the turbo is under warranty, and kind mechanic has offered to take off then refit turbo for less than a tonne!

Just reviving this as I get some smoke from exhaust, only at idle (>30 secs) and only when the engine is warm, ie not cold and not hot..!

No smoke on start up and plugs are always dry and clean.

I'm therefore thinking that an (the..?) turbo oil seal is seeping a little as seemed to be the case for Roojai in this thread..;)

VF35 running ~1.45 bar for the last 18k (in total around 30k on it). If this is the problem is it worth re conning turbo or just replacing..?

;)