Blue Smoke

Noticed blue smoke from my exhaust when sitting on idle for long periods of time.

 

First time when its was in for the MOT sitting on idle blue smoke, smelt of oil, reved and then cleared.

Second time in a traffic but then cleared again.

 

No smoke on boost and only occasionally smoke on idle. 

Turbo is pretty much new, only a few thousands miles (VXR version)

Any ideas?

 

I'm guessing Valve Stems are leaking?

Serviced at BOT only a few hundred miles ago with 0-40 oil. 

 

 

that does sound like the valve stem oil seals are leaking, BoT should be able to replace them for you.

Im guessing you have an aftermarket more free flowing exhaust and or decat ?

Yes Larini full decat (both removed)

Yes Larini full decat (both removed)

Righto Thought so!!!! i suspect it will be the turbo seals. basically the bearings on these turbos are a joutnal type where the spindle1 actually runs/floats on a film of oil. part of the sealing action (i.e keeping the oil in the journal) is caused by pressure in the exhaust system i.e it pushes back against the oil in the journal. now when you replace the exhaust with a more freeflowing one you reduce the back pressure which makes it easier for the oil to seep out into the exhaust system. you often find this happens when the car is running/idling for a long time as 1 the oil heats and thins making it easier to seep and 2 idle gives minimum back pressure. You say it clears on revs. this is due to the increase in pressure when revs are raised

Yes Larini full decat (both removed)

Righto Thought so!!!! i suspect it will be the turbo seals. basically the bearings on these turbos are a joutnal type where the spindle1 actually runs/floats on a film of oil. part of the sealing action (i.e keeping the oil in the journal) is caused by pressure in the exhaust system i.e it pushes back against the oil in the journal. now when you replace the exhaust with a more freeflowing one you reduce the back pressure which makes it easier for the oil to seep out into the exhaust system. you often find this happens when the car is running/idling for a long time as 1 the oil heats and thins making it easier to seep and 2 idle gives minimum back pressure. You say it clears on revs. this is due to the increase in pressure when revs are raised

So most likely need a new turbo?
Only last a few thousand miles is this normal?!

Is the car safe to drive?
Oil is still full (top of the oil stick)

i have seen reports of smoking even on brand new or recon turbos. it appears to be a bit erratic and occurs on some but not others but i think it is probably a trait of the design of the turbo combined with lower exhaust back pressure. i cannot imagine it would do any harm to anything as its only oil burning in the exhaust and if you have no cat it cant damage that. i suppose it depends on how bad it is,how often it happens and whether you can live with it. out of interest has it allways done it or just with the after market exhaust

If the turbo seals were passing oil you would get most of the smoke on boost. If it only smokes at idle, on overrun or at start up it’s more than likely just the stem seals.

Az you can see there are different possible causes. for me the fact that it occurs when hot and at idle suggests turbo seepage. but there are other possible causes as stated. if you could answer the question around it occuring before or after any exhaust mods would help pinpoint the cause

Car has had this same setup for the last 3 years and de-cat and down pipe for the last 6 years without issues.

Same exhaust, turbo etc... no changes

 

Its not a lot of smoke, same about you get out of them bigger E-cigarettes these days. Only happened twice now but my car has been perfect for the last 6 years so I noticed the change.

Car drives fine and still pulls hard, nothing out the norm apart from when its left for ages. Doesn't do this at traffic lights only when left for 5 minutes

Will test from cold tomorrow. 

 

Sounds like oil stems or turbo just not sure if there is a procedure I can do to test which one.

Is the valve stems a head off job? Read some cars can be done with the head still on.

  Just drop the V band off the turbo and check for any end float in the shaft. There will be some lateral play, but if you can feel any end float, it's a fair sign that the turbo is on it's way out. Also excessive oil in the inlet pipework can show up a failing turbo seal.

 

   Failing stem seals tend to smoke the most when you first start up, or on overrun when there is a vacuum in the inlet, so you could try getting someone to follow you at highish revs then just close the throttle. 

 

   You can do the stem seals with the head on using the right kit. I would recommend if you are doing them though, to just buy a decent quality head gasket kit which should have all the gaskets and seals you need, and do it the old fashioned way. The kits are only around £100 or so. Take the head off, give everything a good clean up, re-lap the valve seats while you are at it. You should end up with a smother running engine and gain a few BHP back too.   

Edited by ayresyy, 13 June 2019 - 07:07 AM.

Had the same blue smoke while idling after a "drift session" 12 years ago.

Was also thinking something has to be wrong. I also had (and have till now) a less restrictiv exhaust system.

 

For the next 20000km without any drift sessions an no long idling periods, I had no issues with blue smoke any more and no oil consumption.

Turbo was than replaced by a bigger one, the original one had no play in the shaft and no visible oil leaks.

I would only worry if blue smoke under boost is visible.

Edited by dominik, 13 June 2019 - 10:17 AM.

is there a lot of crankcase venting ?

is there a lot of crankcase venting ?

🙈

is there a lot of crankcase venting ?

Sorry not sure what you mean?

Took off the lower hose from the turbo to the intercooler expecting oil in there but bone dry.
As a few people said don’t think it’s the valve stems now as when I lift off the vacuum would build up and when I get back on the throttle it’s clear.

Only smokes when left on idle and hot!
Compression test booked in tomorrow

as previously stated it all points to oil passing through the turbo spindle seal
idle and your exhaust = lower exhaust pressure
Hot = thinner oil

Just as as input I had the same issue on a Celica turbo with a reconditioned hybrid turbo. Basically it turned out there was too much end play in/out due to wear in the turbo housing I think, so the shaft seal could not seat properly and would leak. It didn't smoke on boost and it was most noticeable after pulling up at a set or lights or junction.

Also had a free flowing exhaust. From my experience valve stem seals will smoke on overrun. There is some test about going down a fairly steep hill on overrun in high revs I think to test for valve stem leakage. Coast down hill and then when you put your foot down again check for smoke. If you have any then it's a sign oil might be getting pulled past the cable stem seals

Edited by james4563, 15 June 2019 - 07:45 AM.

Thanks for your help guys

Compression test was good got 175, 176, 177 and 180.

So turbo has gone, guessing the hot side is leaking directly into the exhaust.

So new turbo required, Courtney Sport do a 360 bearing with uprated seals. Anyone actually know what uprated seals are and is it worth the extra £400+ ????? Based on the fact my last one lasted 3,000 miles I don’t want to changing this out again!

might be worth double checking the turbo before buying another, however valve stem oil seals will give a little smoke on cold start too