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Discussion Starter · #1 ·
I was out today driving my new to me and much loved '06 Cayman - nothing overly aggressive, just bombing around town. On my way back, I suddenly dumped an impressive white smoke cloud out the backend of the car - Panicking, thinking I had blown the engine or done some drastic damage I immediately pulled over and shut her down. Once I was over my initial freakout, and didn't see any oil spilling from anywhere I fired it back up - a little bit of smoke that eventually cleared, and everything appeared normal.

Driving back to my place, the car ran fine, no odd engine sounds, no overheating, but anytime I gave it hard acceleration I was rewarded with a massive smoke cloud again. Is this symptomatic of a blown AOS or should I be worrying about something more severe (read: far more expensive to fix)?

Second question: if it is the AOS, is it reasonable to drive it gently to the shop - about a 15-20 min drive at city speeds away?

if it helps trouble-shoot: '06 Cayman, manual transmission. not raced or tracked. Also don't rev the living bejeepers out of it.
 

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Squish,
You can get an idea if the AOS is failing by checking the vacuum present at the oil filler with the engine idling. If there is a very strong vacuum present it is likely the AOS diaphragm has failed. Your shop should clean your intake of excess oil.

Good luck,

Rob
 

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Discussion Starter · #3 ·
Thanks for the quick reply - I also just realized I put this in the wrong forum...could one of the OPS kindly move this thread over to the 987 forum?

(still frazzled from thinking I had blown the engine)
 

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Discussion Starter · #4 ·
HELP! AOS or something more? 2006 Cayman S

I was out today driving my new to me and much loved '06 Cayman - nothing overly aggressive, just bombing around town. On my way back, I suddenly dumped an impressive white smoke cloud out the backend of the car - Panicking, thinking I had blown the engine or done some drastic damage I immediately pulled over and shut her down. Once I was over my initial freakout, and didn't see any oil spilling from anywhere I fired it back up - a little bit of smoke that eventually cleared, and everything appeared normal.

Driving back to my place, the car ran fine, no odd engine sounds, no overheating, but anytime I gave it hard acceleration I was rewarded with a massive smoke cloud again. Is this symptomatic of a blown AOS or should I be worrying about something more severe (read: far more expensive to fix)?

Second question: if it is the AOS, is it reasonable to drive it gently to the shop - about a 15-20 min drive at city speeds away?

if it helps trouble-shoot: '06 Cayman, manual transmission. not raced or tracked. Also don't rev the living bejeepers out of it.
 

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Re: HELP! AOS or something more? 2006 Cayman S

To check if its the AOS, with the car running, take off the oil filler cap and put your hand over the oil tube to seal it. You should feel just the slightest amount of vacuum. If its strong vacuum, the aos is likely bad.
 

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Re: HELP! AOS or something more? 2006 Cayman S

It sounds like an AOS issue. After doing San Rensho's test, you'll have a better idea.

As for driving it to the dealer, you'll need to consider this. If you're to the point of belching big clouds of smoke on a somewhat regular basis, you probably have a good tear in the AOS. That means you'll be oiling your intake manifold and plugs to some extent - a lot or maybe a little. Worst case scenario is the tear gets bigger and hydorlocks your engine and breaks a rod. Not trying to scare you, but those are possibilties. A flatbed ride may cost you a bit now but save you a lot later.
 
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Re: HELP! AOS or something more? 2006 Cayman S

When you describe the cloud as "white smoke," is it actually white (not bluish) and is it smoke (not steam)? If it's a white cloud which dissipates rapidly, I'd also consider a head gasket leak. Check your coolant level. There have been head gasket failures in the 2006 CS. Hope it's something simple and inexpensive.
 

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Re: HELP! AOS or something more? 2006 Cayman S

I just had this same issue a few days ago. Sounds very similar to my AOS failure. Be careful. If you drive it too much you can make matters worse. It seems like there are varying degrees of this failure, some are able to drive it with minimal effect and others, like myself, may have a more serious fault in the AOS and driving can cause more issues. When mine failed, it sucked enough oil up to foul the MAF beyond the point of cleaning it. So I had to replace both the AOS and MAF. However if you find that the AOS is at fault, you may be able to replace it yourself. After talking with a few other P9s, and doing some research it can be done over a weekend.
 

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Re: HELP! AOS or something more? 2006 Cayman S

if AOS issue, maybe it's an excuse to get the Motorsport one :D
 

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Discussion Starter · #10 ·
Re: HELP! AOS or something more? 2006 Cayman S

Just a quick update - turns out it is the AOS. I have it in the shop right now - waiting to hear if the MAF got all kinds of gummed up as well. It slays me to have to take it to the shop, but I have just recently moved and all my tools are still enroute with the rest of my household goods while I sit and slum it up in temporary accommodation. *sigh*, least it's a relatively inexpensive fix...especially when I initially thought I had blown the engine.

Thanks everyone for the troubleshooting help and recommendations. Much appreciated.
 

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Re: HELP! AOS or something more? 2006 Cayman S

This AOS thing is a real pain! Mine has gone out twice in the last 6 months, oddly both had different symptoms. The first time it sounded as though I had a squealing belt, but it turned out the AOS fail was pushing air through the engine seals. Porsche told me to pay attention for any leaks, but the seals all still seemed to be intact. This time, the car wouldn't crank/start. Out of the blue, no symptoms, no smoke, just wouldn't start. Now Porsche is trying to figure out what's causing the AOS failure. Parts warrantee means they have to find something to bill me for...ha-ha. Kidding. I really want to know what's causing the issue.

For those of you who have had repeat AOS failure, has Porsche ever nailed down a cause for the failure, or did they simply replace it and send you on your way?
Also, anyone who upgraded to the motorsport AOS, is it really that much better? Have you experienced failures since? THANKS!!
 

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I've only had once incident like this and it was after I took a big exit ramp going pretty fast on my way home. The next morning when I started the car I got a large cloud of smoke. that was probably 6 months or so ago and I haven't had any other troubles. I'll try the oil filler cap test but I just figured I wait to see if I got any repeats.
 

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All 3 of the AOS's that failed on my 2002 Boxster have been out of warranty. The first at around 80K miles, the second about 100K miles later and the 3rd about 100K miles later, or at 80K miles, 180K miles, and 280K miles.

I cut one apart and the membrane (rubber/canvas) was cracked/split from what I suspect is just material fatigue.

Really, the AOS is a wear item.

(BTW, on a recent road trip at a dealer getting my Turbo serviced I was talking with the SM and mentioned my 288K mile Boxster with its original engine and even clutch, but with 3 AOS's. He told me of a Boxster owner in the region with 300K miles on his Boxster -- I think it is a 2.5L engine too -- with the original AOS.)

About all I know you can do to possibly avoid a premature AOS failure is to change the oil at reasonable intervals. Oil used too long can build up acid and this can attack the AOS membrane just like other things in the engine that gets exposed to the acidic oil.
 
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