Oil Separator ?

[Captain]

Hey Guys,

The previous owner had mentioned he replaced the "OIL SEPARATOR" that had been causing a CEL. What is it and where is it located? What is it's function?

Thanks,

Harry 1999 996 C2 cab 6 speed

[ivangene]

the oil separator (also called the Air/Oil separator - or AOS) is located on the drivers side near where the motor and transmission mate. Its function is to remove oil from air inside the motor and return the oil to the case and the air to the intake

this is a part that is know to fail. Many many have been replaced. Part costs under $200 and labor is about 6 -8 hours depending on the car (tip/manual, C2, C4)

see pic

[Captain]

the oil separator (also called the Air/Oil separator - or AOS) is located on the drivers side near where the motor and transmission mate. Its function is to remove oil from air inside the motor and return the oil to the case and the air to the intake

this is a part that is know to fail. Many many have been replaced. Part costs under $200 and labor is about 6 -8 hours depending on the car (tip/manual, C2, C4)

see pic

Thanks Ivangene! Wow that's way back up in there. Would the code reader determine a AOS fault if there is a CEL?

Edited March 31, 2010 by Captain

[Loren]

An AOS failure would show as a major (or minor) air leak.

[Beninki]

An AOS failure would show as a major (or minor) air leak.

Maybe I am missing it, but I cannot find a DIY for the AOS replacement. I have the factory workshop manuals and cannot find anything there either. Any help would be appreciated. I am taking delivery of an '00 C4 Cab today, and I know that the AOS boot is leaking and needs to be replaced asap. Thanks!

[1schoir]

An AOS failure would show as a major (or minor) air leak.

Maybe I am missing it, but I cannot find a DIY for the AOS replacement. I have the factory workshop manuals and cannot find anything there either. Any help would be appreciated. I am taking delivery of an '00 C4 Cab today, and I know that the AOS boot is leaking and needs to be replaced asap. Thanks!

The following link is for replacing a Boxster AOS, but it's essentially the same job: http://sites.google.com/site/mikefocke2/airoilseparatorreplacement

Having those hose clamp pliers (or the little blue plastic tool that comes with a new OEM clamp from Porsche) makes the lower clamp on the bellows doable.

Do a search here for a recent (past 60 days) post by Boxtaboy that will give you the part number and a pic of that little tool.

Regards, Maurice.

[Beninki]

An AOS failure would show as a major (or minor) air leak.

Maybe I am missing it, but I cannot find a DIY for the AOS replacement. I have the factory workshop manuals and cannot find anything there either. Any help would be appreciated. I am taking delivery of an '00 C4 Cab today, and I know that the AOS boot is leaking and needs to be replaced asap. Thanks!

The following link is for replacing a Boxster AOS, but it's essentially the same job: http://sites.google.com/site/mikefocke2/airoilseparatorreplacement

Having those hose clamp pliers (or the little blue plastic tool that comes with a new OEM clamp from Porsche) makes the lower clamp on the bellows doable.

Do a search here for a recent (past 60 days) post by Boxtaboy that will give you the part number and a pic of that little tool.

Regards, Maurice.

Thanks Maurice! It does not appear that the AOS has failed- the boot is weeping oil at the bottom. I am hoping that I can replace it without removing everything and or dropping the engine. Any thoughts on this?

[JFP in PA]

Couple of issues: On a Boxster, you can get at (just) the AoS to change it out without removing anything else. This is not the case on most 911 variants where the a lot of the engine components either need to be removed to get at it, or the transmission, and in some case the engine, needs to be removed to gain access. A couple of individuals have done it by taking off components ( Disassemble engine method ), but it is easier with the transmission out of the way. In the case of Tiptronic’s, it becomes a toss up to either pull the gear box or the entire engine. Either way, not for the faint of heart............

[rb101]

You can replace the boot from underneath using standard worm clamps. It's a pain, but can be done, I did mine about 2 years ago and replaced the whole AOS last year. Here are a few links....

http://www.renntech.org/forums/index.php?showtopic=8834&hl=bellows

http://www.renntech.org/forums/index.php?showtopic=13011&hl=oil+separator

Edited November 9, 2010 by rb101

[Beninki]

You can replace the boot from underneath using standard worm clamps. It's a pain, but can be done, I did mine about 2 years ago and replaced the whole AOS last year. Here are a few links....

http://www.renntech.org/forums/index.php?showtopic=8834&hl=bellows

http://www.renntech.org/forums/index.php?showtopic=13011&hl=oil+separator

Rick, thanks very much for the info and the links. Since I am not experiencing the symptoms of a failed AOS, I figured that I would attempt simply replace the bellows and then replace the AOS in the spring when I am planning to drop the engine and transmission to do a IMS upgrade and various other tasks.

Incidentally, I was quoted 8 hours of labor to replace the bellows at the time of my PPI... OUCH!

Thanks again!

Cheers,

Tom

Edited November 9, 2010 by Beninki

[rb101]

You can replace the boot from underneath using standard worm clamps. It's a pain, but can be done, I did mine about 2 years ago and replaced the whole AOS last year. Here are a few links....

http://www.renntech....8834&hl=bellows

http://www.renntech....l=oil+separator

Rick, thanks very much for the info and the links. Since I am not experiencing the symptoms of a failed AOS, I figured that I would attempt simply replace the bellows and then replace the AOS in the spring when I am planning to drop the engine and transmission to do a IMS upgrade and various other tasks.

Incidentally, I was quoted 8 hours of labor to replace the bellows at the time of my PPI... OUCH!

Thanks again!

Cheers,

Tom

It's about a 30 minute job if you can get underneath the car.