996 3.6 - smoke from both exhausts. A head-scratcher!
Discussion
Hi all
I have a 2003 3.6 C2 - recently started smoking from both exhausts on start-up. After a few minutes the oil burns off and all is fine.
I had the AOS swapped a couple of weeks, but the problem only briefly improved.
I've just had leak down/pressure tests done plus a scope into every bore.
The cylinder integrity is excellent and there's no sign of any wear to the bores.
Everything points to it being a faulty AOS but the one fitted a couple of weeks ago was a genuine new Porsche part. There's also not quite as much oil build-up in the inlet manifold as might be expected.
We are scratching our heads as to whether it could be some other element of the crankcase 'rebreathing' system.
Given that:
- oil is definitely reaching the combustion chambers on both sides
- there is zero sign of integrity issues in the cylinders or head
Is there anything else it could be other than the new AOS?
Thanks in advance
Ian
I have a 2003 3.6 C2 - recently started smoking from both exhausts on start-up. After a few minutes the oil burns off and all is fine.
I had the AOS swapped a couple of weeks, but the problem only briefly improved.
I've just had leak down/pressure tests done plus a scope into every bore.
The cylinder integrity is excellent and there's no sign of any wear to the bores.
Everything points to it being a faulty AOS but the one fitted a couple of weeks ago was a genuine new Porsche part. There's also not quite as much oil build-up in the inlet manifold as might be expected.
We are scratching our heads as to whether it could be some other element of the crankcase 'rebreathing' system.
Given that:
- oil is definitely reaching the combustion chambers on both sides
- there is zero sign of integrity issues in the cylinders or head
Is there anything else it could be other than the new AOS?
Thanks in advance
Ian
Thanks Cmoose - some oil in the induction/intake system but I honestly don't think it's residual from the prior failure.
I cross-posted my question to Rennsport - a faulty new AOS isn't completely unheard of. Might have to bite the bullet and have a new one fitted on that assumption.
I was hoping there may be another point of failure other than the AOS diaphragm where oil can be pulled into the intake flow but looks like there isn't.
I cross-posted my question to Rennsport - a faulty new AOS isn't completely unheard of. Might have to bite the bullet and have a new one fitted on that assumption.
I was hoping there may be another point of failure other than the AOS diaphragm where oil can be pulled into the intake flow but looks like there isn't.
Sorry chaps - a bit late in updating this one.
Turns out it must have been an oil overfill when they fitted the AOS - after a few days of some start-up smoke (but gradually reducing in volume) the car is now clean as a whistle, even after being parked up for 3 days.
Relieved and slightly cross at the same time.
Turns out it must have been an oil overfill when they fitted the AOS - after a few days of some start-up smoke (but gradually reducing in volume) the car is now clean as a whistle, even after being parked up for 3 days.
Relieved and slightly cross at the same time.
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