Air/Oil Seperator write up?

[Brad Roberts]

I'm about to write one up with GOOD pictures, but decided I'd better check with the "locals" and see if a good one was already somewhere on the site. I used the search *feature*, but as with most forum software.. it is close to worthless.

Let me know if I should continue. I'll walk everyone through step by step with HIGH quality pics and a breakdown of the tools needed, and how I make one small change to the install procedure.






B

[steve00s]

There are a couple floating around out there somewhere but if you are preparing one I am sure it would be much appreciated.

[Brad Roberts]

I'm currently going through and cropping the pics + adding arrows and such


B

[FTD]

+1 encouragement to go forth

[Brad Roberts]

Working on the verbage

WHOA! Went to upload the first pics and the server took forever!! Let me post them on my server and I'll link to them from there!


B

[cas951]

Great. Please post the link.

I'm approaching my 1 year of ownership and to this day I have not opened up the eng compartment lid. I will be going in within the next week and AOS will be one of the things I'll be doing.

[kevinniven]

Just called the shop, they want $300 to replace.
Is this truly something the avg person can do at home?
thx guys

[mikes_box]

Originally Posted by kevinniven

Just called the shop, they want $300 to replace.
Is this truly something the avg person can do at home?
thx guys

$300 for parts and labor is not bad at all. It can be done at home for a few hours of work and cursing for about $100 in parts.. If you do it at home make sure you buy the hose clamp pliers and a new hose clamp that you can jus screw ith your fingers...

[Kevfra]

Quote: Most of the failures I do see involve cars with 60-70k miles on them, and it appears to be heat related (air temp 100+ and ground temp 115+) which would equal REALLY high engine compartment temps. This is the ONLY "common" denominator so far. End Quote.

Well mine failed at 60,000 miles on a 102 degree day in slow traffic, so compartment temps were extremely high, plus AC running full tilt. One wonders... why put a heat sensitive part up against an engine?

Two points to mention - I found that using a small vise grips on the bellows clamp during removal was the way to go, as simply using pliers wouldn't do the job.

And second, regarding removing the compartment cover, the ball/socket cable on mine has a small C clip that has to be removed before popping out the ball. Swing the C to the side, then raise it until it comes clear, then pop the ball out.

Fabulous write-up and extremely helpful - many thanks Brad!

[Tool Pants]

The temperature related theory is interesting. However Peter Smith thinks it is due to cold air that causes the rubber diagraphram to split.

Unlike the Boxster, the separator on a 996 is heated by coolant. This is a 996 separator and you can see the 2 provisions for the coolant hose into and out of the round thing which is the diagraphram.

[Kevfra]

Well I replaced mine - and still have white smoke, although perhaps not as much. I have to drive it to see if it clears, and if the sucking comes back to the oil cap.

Isn't this thing just a minor smog control device, to capture vapor from the crankcase and burn it? In the old days (and on other cars) that would be a very simple matter. This thing seems overly complicated and prone to failure.

[chrismanchr]

Originally Posted by Tool Pants

The temperature related theory is interesting. However Peter Smith thinks it is due to cold air that causes the rubber diagraphram to split.

Unlike the Boxster, the separator on a 996 is heated by coolant. This is a 996 separator and you can see the 2 provisions for the coolant hose into and out of the round thing which is the diagraphram.

I can maybe confirm this thoery about cold air ,as my AOS (2.7 987) failed on the coldest day of our winter so far ,it was -17c ,and the engine been running very rough since ,plus an oil drip down the back of the AOS ,the engine sounds like its either got an exhaust leak or induction leak or both ,plus slight oil smoke like one of those misting machines you use to get at 1980's discos

when calling a porsche center for the part they have had lots of orders for the same part ,the 987 AOS is a bit different from the 986 version and doesnt have the boot or the plastic tubes on the bottom but a hose (with one of those clips that are sometimes impossible to remove) and a spigot with an O ring ,also mounted / bolted differently

[bar10dah]

Bump! Just looking for the pics from Brad Roberts.

[Brad Roberts]

I know I pushed them to the server, just need to go and edit all the url's for the pics.


I'll see what I can do. We are abnormally busy at the shop for this time of the year



B

[bar10dah]

No worries. Understand about being busy.

[jaykay]

Last time I was in my engine bay my AOS had a film of oil on it so it may be on its way out. Do any feel the motorsports version is worth the additional cost?

I had an oil leak after a track day and thought (or hoped) it was the AOS.....but then the drip moved into the centre....gulp....track weekend over

I had partially dislodged a new 997 RMS. Could undue crankcase pressure via the AOS be part of the problem?

[AndyA6]

Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!

[Mark_T]

Thanks Brad - That is a really good tutorial. If you're not a tech writer, you should be!

[Brad Roberts]

26 years of Porsche wrenching and I ran my own Porsche web forum for 8 years This writeup was what I consider "half-ass" LOL I was at home and not at the shop when I decided to do this. I know what info a mechanic needs and I know what the "home user" needs


B

[RandallNeighbour]

Brad, thanks so much for this. I always wondered about the AOS and now I know what it looks like, where it's located, and how to swap it out when my car starts billowing smoke! One hour too. That's totally doable.

On an older boxster like mine with 110k on it, do you recommend swapping it out as a preventative measure?