Can I delete my AOS from the intake? (09 Cayman base)

[matt1415]

Long story short I'm working on a friend's 2.9L with the usual smoke on startup issue and oil in the vacuum lines going to the intake. I changed the oil air separator but nothing has improved, still sucking in oil to the intake. There is obviously a bigger problem here like failing Nikasil coating on the block but he just doesn't want to see the smoke on startup. My question is can I just vent the AOS to the outside with a separate hose rather than doing it through the intake? Is there going to be any negative effects on the engine other than the reduced blow by?

Thanks

[JFP in PA]

Originally Posted by matt1415

Long story short I'm working on a friend's 2.9L with the usual smoke on startup issue and oil in the vacuum lines going to the intake. I changed the oil air separator but nothing has improved, still sucking in oil to the intake. There is obviously a bigger problem here like failing Nikasil coating on the block but he just doesn't want to see the smoke on startup. My question is can I just vent the AOS to the outside with a separate hose rather than doing it through the intake? Is there going to be any negative effects on the engine other than the reduced blow by?

Thanks

Only if you don't mind risking blowing out every other oil seal in the engine, and suffering power loss because the rings do not seal properly.

Most likely, what you are seeing is residual oil in the intake system being burned off. You can either live with it until it abates, or pull everything apart and clean the oil out.

[matt1415]

Originally Posted by JFP in PA

Only if you don't mind risking blowing out every other oil seal in the engine, and suffering power loss because the rings do not seal properly.



Most likely, what you are seeing is residual oil in the intake system being burned off. You can either live with it until it abates, or pull everything apart and clean the oil out.

I'm going to start by saying I respect your opinion on this topic or else I wouldn't be asking. With that said, what "oil seals" are we talking about here and what factor as a result of re directing the AOS vent causes them to fail?


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[JFP in PA]

Originally Posted by matt1415

I'm going to start by saying I respect your opinion on this topic or else I wouldn't be asking. With that said, what "oil seals" are we talking about here and what factor as a result of re directing the AOS vent causes them to fail?


Sent from my iPad using Tapatalk

Crank seals, cam cover seals, cam plugs, plug tube seals (depending upon year), etc. The AOS provides a slight (5 inches of water) vacuum on the crankcase to prevent these seals from blowing out, and to allow the extremely low tension piston rings to seal properly; remove that vacuum source and you are going to have pressure in the sump which will lead to problems beyond just oil leaks, such as getting oil all over the clutch when the RMS pops loose, poor ring seal, causing significant blow by and oil consumption, etc.

The AOS is there for a reason.......