the_vetman

The price I quoted above was for stock non-motorsport AOS. 987 motorsport AOS used to be around $1,300. Porsche has raised prices on all parts since then.

Macster

While I hate to revive an old thread, I missed this when the thread was current. Had I not missed this I would have responded.

So, just for the record, I drive the car roughly 1891 miles per month on average or 22.69K miles per year. (Bought the car new in Jan. '02 and the car currently has almost 279K miles.)

Two AOS's failed. The original one, the 1st one, at around 80K miles. Its replacement at IIRC (make that WAG) 100K miles later. The replacement for the 2nd one, that would be the 3rd AOS, is still working fine with around 100K miles on it.

Keeping the oil reasonably fresh and thus its acidity down helps the overall engine health.

What I do not know is I do not know if it makes any real difference in the life of an AOS. One AOS I cut apart suffered a crack/split in its rubber diaphragm. Whether this was somehow caused by the oil or delayed by the oil I really have no idea.

I note while the engine has not suffered any issues from the miles -- other than a VariCam solenoid/actuator at around 240K miles -- the car is on its 3rd AOS. However, the 2nd AOS lasted around 20K miles more than the original one (and the 3rd is likewise having a -- so far -- long and uneventful service life -- given all the variables remain essentially the same.

The oil still gets changed every 5K miles and mostly I run Mobil 1 0w-40, though I ventured to run Mobil 1 5w-50 (not a typo for 15w-50!) for a while but came back to 0w-40. (The 5w-50 oil became harder to come by and I just didn't want to bother.)

My usage still has me driving the car about the same number of miles per time period and I drive the car the same way, etc.

I must stress that I still advise an owner to follow a more frequent oil/filter service even though it does not appear to have any obvious benefit to AOS life.

While I would prefer the AOS last a long time I do not have a problem replacing the AOS every 80K to 100K miles. I do have a problem, or would have a problem if I had to replace the engine that often...

Bartmack

Thank you.. and I must say I am delighted to hear about the overall longevity and durability of your 986! 280k is kind of awesome.

blue44

+1 !

Donn

TomiK

Just thought I would add my 2c...

I replaced the AOS on my 2008 Boxster S at 40000 miles - the diaphragm split and the engine emitted a high pitched wail/screech (from excess pressure I am told) after a hard drive home. New AOS (original part) cost $100 (in South Africa) and it took me two hours to replace using a DIY from a forum (quite easy, but a bit fiddly with small spaces to get into, no special tools required but clamping pliers help to get the clips off the pipes).

needmoregarage

I track my Cayman R and recently had clouds of white smoke appearing twice on start up over the period of one week. The smoke appeared the first time when the car was warm and had already been started twice and driven that day. Smoke lasted more than two minutes. I started the car a third and fourth time that day and it ran normally (no smoke). The second time was five days later (the car sat undriven) the smoke appeared on cold start up and lasted more than 3 minutes.

The dealer diagnosed a failing AOS. They were not able to duplicate the smoke (they started several times over the week they had it) and did leak down test. All was good - but when they looked inside they saw oil (small amounts) in places where they shouldn't see it - and diagnosed AOS beginning to fail.

They replaced under warranty (car has 23,000 miles). I asked about a more robust AOS option after researching and learning this is a weak link in Porsche 987's and 911's. I was told it was a documented problem in the 987.1 and there is a more robust AOS for first gen Caymans - but for the 987.2 there is only the OEM option.

After reading the previous posts in this thread I am unclear if the after market AOS is only for the first gen Caymans or if it would have been an option in my car.

I spoke to the dealer's tech who worked on the car - and he said AOS can last tens of thousands of miles (maybe the life of the engine) or they can "go" at any time. Somewhat luck of the draw, and obviously more likely to fail when the car is tracked.

I have great faith in the dealer and their tech team. I'm a bit underwhelmed that Porsche would continue to have a weak link such as this in an otherwise spectacular car. I'm hoping my new AOS lasts a long time.

Schmidts Cat

Interesting.... I have been getting some unexplained smoke too at stat up... Even when warm, but not always. I'll get this checked. I'm at about 22,000 mi, but track more than a bit.

Macster

There is a motorsport AOS. It costs almost $900 (vs. the $120 the regular one costs). The motorsport AOS doesn't fit all model years. I think primarily it is a nearly bolt in replacement for 1999 to 2003 or 2004 cars but others require some extra effort and it might not even work at all on newer model years.

Pelican Parts web site has some info the motorsports AOS.

And it is time for an update. My Boxster now has over 285K miles.

Everything was fine, the engine has never run better, no more CEL after replacing the rattly converter (and its quiet mate on the other side) with a pair of converters sourced from a salvage yard.

Then just a few weeks ago, just about time for me to take the car in for its 5K mile oil/filter service, the 3rd AOS failed.

No warning. Like I said engine has never run better. Drove 10 miles from my house to where my Mom and Dad are living and a few blocks away I caught a red light. Light changed and I accelerated -- normally -- away and made the left hand turn.

I glanced in the rear view mirror and saw the densest cloud of smoke I've ever seen. Checked the dash and no warning lights. Engine was running just fine.

Long story short I aborted my visit to my Mom and Dad and decided to drive right over to the dealer and get the car in, ASAP. Made it just a few blocks until the smoking got even worse and then the engine started running a bit rough.

Pulled into a parking lot and parked the car so the tow truck would have no problems getting the car out.

Called AAA and a few minutes later the tow truck was there and picked up the car and 15 minutes later rolling the car off at the dealer service department drive.

AOS of course. Roughly I estimate this one when it failed had around 100K miles on it. So I had the 4th AOS installed along with new plugs -- the old plugs had been in the engine for 100K miles. (I lost track of the miles.)

Oil/filter service done.

No smoke when I picked up the car but engine had a tiny bit of stumble. I attributed this to probably a dirty (oily from the AOS failure) throttle body. (I have seen this before with an earlier AOS failure. The first time I removed the TB and cleaned it. The 4th time? Meh. It will clean itself.)

Drove the car home and at home did an e-Gas recalibration.

Drove the car around until the engine got nice and hot and no more stumble. Engine has been running as good as ever again.

Oh, when the tech did the plugs he found 2 of the 3 tubes on the driver's side leaking. When he pulled the tubes out -- they were wobbly -- the o-rings came out in pieces. He got the 3rd one out -- it was tight -- and replaced all the o-rings on that side. (The other side tubes were not leaking and the tubes were not loose.) So the engine is once again oil tight.

needmoregarage

Macster - thanks for the info and update. Congrats on an amazing run with your car, and I hope it provides joy for another 285K miles!!!

I checked into the alternate AOS and was told it's not for the 987.2 generation. It is for prior generation cars, and for mine there was no option other than OEM.

After picking it up from the dealer I went promptly to Watkins Glen for two glorious days and the car ran beautifully. I drove it there and back (over 600 miles round trip not counting miles on the track). At least next time - if the AOS fails again (and sounds like eventually it will) - I'll know what the smoke is about!

roofrack

In late 2011 I received a replacement engine "AT" from Porsche due to IMS failure. Was wondering if that means I also received a new AOS? Where is it located? Does it come on a replacement motor? Car has 77K miles total and almost 14K on the new engine. Oil changes at 5K miles give or take... 2006 Boxster base.

Macster

The replacement engine comes with a new AOS.

The AOS is located on top of the engine towards the rear of the engine and a bit offset to the right side. If you expose the engine (from above) and locate the throttle body there is a hose connected to the intake downstream of the TB. Follow this hose over to the right and it will lead you to the AOS.

Here is a link to a thread on the Pelican Parts web site that has a few pics of the AOS. (I'd post one of my pics, but they are all on DVDs right now and I haven't transferred them to my laptop.)

http://forums.pelicanparts.com/boxst...separator.html

Relax. The odds are very high that AOS will give you 80K miles (or more) of good life before it acts up, so you have 66K miles ahead of you.

roofrack

Thank you for the reply and link. Cushion of 66K miles makes me feel more comfortable! Gonna keep on driving her...

Noah Fect

Are these AOSes still used on the 981?