My 2007 Cayman S Extreme Exhaust Smoke

I've had my 2007 Cayman S exactly one year and love it!!!! But, I was just driving home from the store and gently pulled out of the lot and noticed a HUGE trail of smoke from the exhaust. it was more grey than blue and would reduce sometimes as I went faster. I was very close to home so decided to drive it is water temp was ok and the check engine light had not come on yet. As I got close to the house I noticed a high pitch whining from the engine that was intermittent and the motor started running rough at lower RPMS. The whining did not change sound as the RPM levels changed but was pretty consistent I'm pretty sure I am in for some bad news. When I parked in garage, there is no oil anywhere, nor on the street or driveway I let it cool down then checked oil level - almost empty! Thoughts anyone? Thanks in advance and P.S. I track the car once a month.

AOS...alarming, but not fatal. Quite a few threads on here if you search for AOS or VOS...

Yep, sounds like the AOS has failed. Not expensive, and not too hard to replace if you're a DIYer.

Thanks gents, I will study the links. I was shocked at the amount of smoke and that my oil could be so low. In your opinions, is AOS failure more likely than the dreaded IMS failure mode? I'm a newbie and this is my first post to this site, but I can tell it will be very valuable network. Thanks again.

Classic AOS symptoms - massive smoke, unusual / excessive oil consumption, and rough running engine. Your CS is running rough at low RPMs because you've coated the combustion chamber with oil. The AOS is like a PCV valve - it redirects gassy air back into the crankcase. What keeps actual oil from getting into the crankcase is a thin membrane in the AOS. If it gets a tear or puncture in it, oil will leak into the combustion chamber. As the tear increases, more oil gets in and you get the James Bond smoke screen. The tear will increase with high, sustained RPMs (like at a DE). Worst case scenario is you get massive amounts of oil into the combustion chamber and you hydro lock a piston. Game over at that point - you have a boat anchor with a broken rod. So don't drive your CS until you get the AOS fixed. Tracking your CS puts more pressure on the AOS than just street use. There's a $1300 alternative that a lot of track rats use that replaces the AOS and eliminates the problem. I've taken a more practical approach - I can replace a lot of AOSs at $85 before I get to $1300, so I have a spare AOS on hand and take it to long distance DEs as a precaution. The other thing I've done is put an IPD plenum on (along with a GT3 throttle body). The IPD uses 1 less hose to the AOS, so there's less pressure on the AOS and it should last longer. Don't mention the 'I' word or you'll have all the vultures circling this thread. If you had that type of failure, your engine would sound like a bunch of loose marbles and would run very bad for a short period of time (until it destroys itself).

If your gauge showed any bars, you were a long way from "almost empty". In fact, you were still at a safe level. Your engine holds about 8 qts and you were probably only down a qt from the max level. I usually don't keep my car at max.

This is very good news to hear. I just added my IPD plenum a few weeks ago in my 10 year old CS. One hose blocked off. With my AOS being original and now likely getting brittle, I was wondering if at some point I should replace it proactively "while I'm in there." Likely to get the 997 GT AOS and keep it on hand pending failure evidence. Right now, with only 24,000 miles, the only thing concerning me about the current components is age and drying.

Thanks so much for the additional information. I really appreciate it. I feel much better this morning that it isn't as dire as I thought it may be. I'm still wondering what the intermittent squealing noise from the engine was that started about 2 minutes after I noticed the smoke. I listened closely and the frequency was consistent - not changing with RPM increase/decrease. Any last thoughts on that? Thanks again and I will refrain from the "I" word..

Eeek: $88 for the standard one at FCP. $1800 for the motorsports one, on sale, at a popular vendor whom I shan't point fingers at.

There are early warning signs if you keep an eye out for them - a bit more smoke than "normal" and a bit more oil consumption than usual. No need to panic at that point, but time to get one on hand if you don't have one ready and plan ahead for a change date.

The squealing is a common symptom of failed AOS too...

I have a 2005 Boxster S and the AOS went under the exact same circumstances. I drove into a parking lot just fine. Came out an hour later and started the car. Huge cloud of grey smoke. Drove it home about 4 to 6 miles and then to the dealer, another 3 miles, AOS replaced and has run like a charm for 18,000 miles and 2.5 years. You should be ok but it is very scary considering all the ims brew ha ha. Good luck.

My 986S squealed horribly when the AOS went- so bad I thought I had a seized pulley! No smoke, though, until I pulled the oil cap and ran the engine. THEN it started blowing smoke, lol. You can drive on it with the AOS blown, but there is a risk of hydro-locking the engine with oil, running the oil too low, and fouling the intake and O2 sensors with oil. After the AOS is changed, expect some lingering smoke and spurious CEL codes until the oil burns off. I suspect overfilling oil increases the chance of AOS failure, so be careful to not overfill.