AOS. Old? New? Newer?
 

So I've read enough in the forums to understand the importance of the AOS, and how it can flop anytime and unannounced.

A while back, when I was cleaning the throttle body and such, I wiped off the AOS and recognized it as an "older" AOS because the top was round. I knew that the "newer" AOS arived with the top, if you will, the round top... now was on the side. OK.

So, I finished my gig... put the lid back on the engine... closed it up.

Frequently read the forum posts... follow leads... and stumbled upon a post illustrating and describing how to replace the rubber/silicone diaphragm... and that you could do this only upon an "older" AOS, because the "newer" ones were sealed. Sealed meaning the round top... cap... couldn't be removed. The post illustrated how to remove the top on the older style... with the four prong-looking things you would finagle, each slowly, until the lid popped off. It was an R&R from there.

So... I purchased a couple of those diaphragms thinking I would mitigate having to replace the AOS with an $8 fix.

Yesterday went to check the diaphragm on the AOS. No tabs. Those four tabs, an Noon, 3, 6, and 9? Not there. I examined the top with a light... and it appears that the lid... the top... the round... is sealed on. So... this leads to some inquiries for which I'm hoping someone can provide responses. Thank you, in advance.

1. Did the 1998 Boxster arrive with an AOS with the removable top, with the 4 prongs?

2. Did the 1998 Boxster arrive with an AOS with a sealed top, absent the 4 prongs?

3. In order of market arrival would it be: A. Round on top, with 4 prongs. Then maybe a "part improvement" with the next version arriving, B. Round on top, sealed. Then followed by the current version with the "top" on the side, and sealed. Just wondering if that wasn't the development progression.

4. Would the AOS, in my car now, as I described... round on top, sealed, be the second AOS in the car? That's assuming it arrived with the "first generation... round on top... 4 prongs.

Thank you for your consideration.

You are nuts trying to save a buck by replacing the diaphragm yourself. You are putting the car at risk in order to save a few bucks. Do yourself a favor and buy a new AOS from the hosts of this forum. A genuine Porsche AOS is only $102!

Especially considering that you are not an experienced mechanic or DYIer.

Suggestion. Post the model year of your car in the message. Helps the person trying to answer your questions.

Unusual that this forum doesn't provide a means to store in the profile or display with each postings the P-car ownings of the posting person.

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Sorry. 1998 Boxster.

I'm fairly handy (89' 535i ~170K. 86' 325es ~290K).

It wasn't the $102... it was what I believed a prudent way to go. IIRC there are no internal moving parts, and the only 'wear' item, aside from gaskets, is the diaphragm. The install doesn't frighten me, as I'll be taking off the rear wheel... removing shrouds... and tackling it from above and below.

Unless someone suggests otherwise.

Thank you for your continued consideration of my inquiries.

I'd just replace the whole AOS, clip(comes set up to drop in), upper pipe(996-107-145-06), and lower seal. You should not need to remove the wheel. That lower bolt is easy enough to access without going to that. You'll need to put the top in "service position" and get some access through the upper engine access panel.
Good luck with it.
Regards

1. Did the 1998 Boxster arrive with an AOS with the removable top, with the 4 prongs?

2. Did the 1998 Boxster arrive with an AOS with a sealed top, absent the 4 prongs?

3. In order of market arrival would it be: A. Round on top, with 4 prongs. Then maybe a "part improvement" with the next version arriving, B. Round on top, sealed. Then followed by the current version with the "top" on the side, and sealed. Just wondering if that wasn't the development progression.

4. Would the AOS, in my car now, as I described... round on top, sealed, be the second AOS in the car? That's assuming it arrived with the "first generation... round on top... 4 prongs.

Thank you for your consideration.[/QUOTE]

1. I have been on this forum & others since about 2005 daily & never heard or saw anything about a removable diaphram.

2. I was "positive" the 1st gen AOS with horizontal diaphram was discontinued sometime in 1997 when the new current version was fazed into production.

3. To the best of my knowledge "3" is correct if you eliminate "A".

4. Is your Box a USA car?

I have a 97 that still had the original 'flat' AOS in until I changed it a few months ago. It was sealed and not serviceable at all. I'm also pretty sure there was NO version of the 986 AOS that was serviceable.

What I think happened (pure speculation...) is that some cars (e.g the Cayenne) do have a replaceable AOS diaphragm, but Porsche stopped selling them individually (see Porsche Cayenne Repairing the Air-Oil Separator | 2003-2008 | Pelican Parts DIY Maintenance Article) ... some 3rd parties started making and selling them on eBay, and incorrectly labeled them as compatible with the 986, thus creating this confusion.

Yes. That would be the one. Arghhh. So, it'll be the complete AOS replacement... when that time comes.

If anyone has the "serviceable" AOS I've 2 new diaphragms. PM me.

I actually give the OP a thumbs up for taking DIY a step further than general parts replacement. Individuals like this are good people to have around as they can teach us a few things. If he had a bad alternator he would probably try to see why and replace a worn brush for a few bucks than several hundred for a new alternator. Most shops replace the whole component because Time is money and they also make money on the parts. This thread sure taught me something new.

Thank you.

I pursued that direction because the part was, literally, staring me right in the face. And, the diaphragm replacement seemed the obvious, first, easiest, and least costly, replacement measure. Especially since there was the step-by of the process. No biggy to replace the AOS, although I was disappointed to see the absence of those tabs.

I won't be needing the 2 diaphragms I have, if anyone's interested. Gratis.

Thank you for the compliment. If I had what I diagnosed as a bad alternator I might take it to the alternator shop in town.

Finally, anything I know about my car I've learned from this forum. Tricks. Techniques. Methods. Tools. Ancillaries. Virtually an answer to any question one might have.

Thank you.

I did my 98 not long ago. It had the original horizontal round top. You will find the original vent line from the throttle body to the AOS will be short for the new AOS. Even if you could service the original I'm not sure you could get a new vent line, if you were to break it. I found a number of the plastic parts in there were rather brittle and broke a few of them trying to get the AOS out.

Here's the thread on that. http://986forum.com/forums/boxster-general-discussions/69319-oil-air-separator-vent-line-short.html

When I cleaned my throttle body I removed that line.. and it was/is solid as a rock. Nothing brittle about it. Looks as good as new.

I did see the new AOS... it's in my project list along with 2 lines. On Peli it shows 2 lines. 1 for upper line and 1 for lower line? If I purchase the new AOS, do I need both of those lines or just the top one? Thank you.

I know I'll be discarding the existing upper line. Likely, after I install the new one, the old (solid) line will be up for grabs.

If I purchase the new AOS, do I need both of those lines or just the top one? Thank you.

This Forum operates on a platform that was originally used for internet bulletin boards. The original version (Ver 2) was launched in 2001 with Ver 3 launch in 2004. Ver 3.8 (the site runs 3.8.7) was released in 2011.

It still probably supports 1200 baud AOL dial up connections. :)

you can put them in your signature and they will be included automatically at the end of each of your posts.

The cars are 1997 - 2004. I think the forum will be fine as long as we remain compatible with Win 98 and AOL dial-up access.
:cheers: