sr20det oil smoke on decel

[Croustibat]

Originally Posted by joshfng

I've been doing some more testing. It appears as though it only smokes after decel only after I've been boosting which leads me to think turbo (but again no shaft play and no oil in the intake pipes). Also there's no smoke on decel when I've stayed out of boost.

I dont know. But you need to check the turbo on the exhaust side. No play in the shaft does not mean the seals are ok. You checked the intake is ok, but there is another at the exhaust.

Have you, or have you not changed your exhaust system or the intercooler for a less restrictive one less than 4000 miles ago ? If the answer is yes, then it is a turbo seal leaking.

I also have another theory that you will absolutely not like, but here it is: you may have leaking rings. Off boost it is ok, not a lot of pressure to hold (talking about gas pressure during combustion, not boost). Boost comes, rings cant cope and leak pressure to oil pan. Pressure in the oil pan is now superior to pressure in the exhaust => turbo oil goes through the turbo exhaust seal instead of going to the oil pan.

You need to make a dry then wet compression test.


But again, this means oil goes through the turbo exhaust seal. The reason this time is not that the seal is broken, but the way it works; oil will always go where there is less pressure ( that is supposed to be your oil pan ). I think some turbos use another kind of seal that does not care about that, but not entirely sure.

That is the reason why drag cars running with tons of boost have a vacuum pump in the oil pan, as the rings WILL leak during the run, but oil still needs to come down from the head and the turbo(s).

Originally Posted by joshfng

The car smokes a tad when it is started cold after sitting all night but after it's warm there is no smoke at idle.

This has nothing to do with your problem. It is called "nightly moisture going through the exhaust".