Blue smoke after de-cat

[dgjdrummer]

Hey guys, need some advise.

I fitted my Toyosports downpipe decat on Wednesday night, since then I've had very pale blue smoke during low revs and a small wisp on idle as well. The symptoms are:

- Blue smoke at idle (wispy)
- Heavier smoke during part throttle
- Smoke only up to 1500rpm, seems to lessen and then completely disappear by 2k

It seems to be rev related rather than boost related as the smoke is there whether I'm using constant throttle or flooring it up to 1500rpm. I think the exhaust is hot enough to vapourise the oily smoke over 2k maybe?

Does this posing to anything specific or is it a number of possible things? Have read about valve seals, how hard are these to change?

Possibly turbo seals? I know this would require a refurb or new/uprated turbo which I can't afford at the moment...

Cheers.

 

[troupy]

stem seals?? turbo would puff white

 

[dgjdrummer]

Would stem seals not get worse as revs increase rather than being within a set rev range?

If it is seals, how difficult are they to change or how much would I be looking at?

I did notice while change the dp that there was a small collection of oil on the underside of the turbo.

 

[Dan FR]

Sounds like turbo to me, removing back pressure will highlight a weak/ageing turbo - its just oil escaping, not a sign of imminent complete turbo failure.

Put the cat back on and it will likely go away. Smoke from the turbo will vary in colour depending on which side it is leaking from and whether the oil is burnt by the engine or the exhaust

Was there any oil inside the hot side of the turbo?

 

[dgjdrummer]

I've read that can be the case, hoping it's not the turbo on the way out

It is very pale almost white blue, heavy enough to leave a cloud but it rises past the rear window as I'm driving so not really bad.

I didn't notice any but I did a Mr muscle and carb cleaner clean on it almost straight away. None ran down the mating face and I didn't notice any on/in the flange of the dp though. Cheers for your help so far!

 

[dgjdrummer]

Ok, been back under the car today. There was a decent amount of oil seeping out between the downpipe and mid pipe, not a problem in itself but proof the oil is getting through on the exhaust side as opposed to the engine side.

I took the oil return line off and it was clear, no kinks and no crud in the compressor housing that I could see. Took the TIP and dp off to check the turbo shafts, there was negligible side to side play but enough in/out play that I could feel it by pressing on each side of the shaft and wiggling it back and to.

There was a small (tiny) amount of oil in the turbo hot side and none in the cold side, most of the oil seemed to have pooled in that join between the dp and downpipe. I've put everything back together, been out for a run and initially there was less smoke but it seemed to be back to normal when I got home

I'm pretty sure now it's the turbo oil seals that have gone, I'm going to have to find either a cheap second hand unit, a cheap refurb place or just bite the bullet and upgrade it now and run the standard map!

Anyone with any suggestions/advise?

 

[Budgie325]

I'd clean it all up, and check it again in 500 miles, just to get an idea of how much it's losing tbh.

 

[dgjdrummer]

Well my oil level (which I knew to be ok a week or 2 ago) was down to the min marker yesterday and I had the oil light come on this afternoon before I pulled everything apart. So it's gone from just under maximum after I serviced it in January to minimum yesterday and low oil light today :/ only fitted the dp on Wednesday!