Sadly joined the failed AOS crowd ...

My beloved 07 CS. (161K Miles) had an AOS failure at 80+ mph on the highway..(apologies to those 10-15 cars behind me who were plastered by my smoke and oily mist) Car gave me 2 "oil pressure low" warnings an hour before the failure.. I checked the oil and oil level was good.. Warnings went away.. but an intermittent loud screech returned.. Just before the full blow up, the screech returned Car lost 1 Qt of oil (from what I can tell) I have procured a new AOS from dealer but am waiting on a Breather hose to complete the job DO NOT put this off.. get it done before it becomes a problem Not a hard job even for an amateur like me, but all this paid could have been avoided.

Bummer. Hope you do not have too much trouble cleaning oil out of all the places its not supposed to be.

I am all done with the cleanup.. replaced air filter while I was at it.. MAY have to replace MAF but no codes while I was coasting.. oil was everywhere... any residue I can't get to will have to burn off on its own... Will replace spark plugs too but once I am sure the issue has been resolved Just waiting on the crankcase breather hose to put everything back together

Desmotesta- You have one of the highest mileage M97 engines without a rebuild on P9. Any tips on how not to destroy your engine. AOS , I had the same thing happen to me at a local autocross. I was a big attraction in the staging area as the fellow competitors thought I blew up my motor. There is a drag strip associated to the autocross track, so I made a few full gas runs to help clean out the oil from all the parts. Later that week, I had my shop install a Porsche MotorSports AOS . No issues after that with the AOS even running Hoosier A7's. When talking to the install shop, they told me that the reason I oiled down my AOS was I had overfilled the oil sump, believing that I should have a full sump. Not so, according to LN, who made the deep 10 qt sump, I should have been running less than 1/2 the gauge or 2/3 qt less than max. I now run 2/3 of a qt low as per LN/Cantrell motorsports recommendations while using this sump with windage tray, even with the Porsche Motorsports AOS .

Welcome to the 'club' Well I was driving my 06 CS MT & being pestered by a Jeep on a very twisty low speed road. Knowing that a sharp, near 270 degree, right uphill turn approached, I baited him a bit and let er rip! Hmmm he and the other 3 cars behind him disappeared! No, not from speed but from the mammoth cloud of smoke I produced. Coasted her into the quiky mart...could almost hear the sneering haha. Informed ahead of time thanks to P9, no panic. Put er all back together (inc plugs/coils/cats) and she ran ok but was giving me stumble about 5k and up. After having to buy a 5 point torx driver (tearing out some hair as I had 100's of bits/wrenchs/etc etc that wouldn't loose the damn MAF, using a mirror this I discovered) I then used the official MAF cleaning spray and voila! Never ran better. Just a heads up and good luck!

Can you elaborate on the official MAF cleaning spray?

I honestly dont know what to tell you.. I bought the car with 142K.. previous owner babied the car and never drove it hard (claimed), over rev reports 0 over revs in any zone I change oil every 5K like he did.. I use Castrol 0w40. (he used M1 all its life)... I have Soul Long tube headers, milted exhaust and a tune.. I drive it hard 90% of the time.. but I never rev past 6000-6200..never.. there is no point (on streets) I have a couple of motorcycles and straight-line "speed" is not what I have the car for... Apart from not redlining, I am flat out and Full throttle most of the time.. I HOPE it can make it too 200K.. and judging bye how things have been going (apart from AOS) I have no doubt that I can get there

Happy to share that my baby is back on the road After hours of cleanup, replacing AOS , Crank case vent hose and a vacuum hose... I was finally able to crank her up Cant tell you how much I was cringing, feared for metallic sounds from engine etc It seems to be a happy ending for now.. hope many more miles to go... Hard work DOES pay off... I feel like I was beaten with a baseball bat, but it was SO worth it

Sorry for the delay... "CRC 05110 Mass Air Flow Sensor Cleaner - 11 Wt Oz " for example. Auto store or A%azon. Mine has been perfect, perhaps even peppier, after the AOS fog and subsequent plugs/paks/cat refresh. Glad to hear you're running again!

thank you.. Mine is hesitating on Full throttle. I did not change the MAF, didn't clean it yet either. Have no codes.. just hesitation

I agree, this is an easy and fairly cheap (at least in the Porsche world) PM item. It takes an hour tops. This hose clamp plier is a must in my opinion. Hope the picture works. If not, it's the one with the cable operated clamp tool. https://images-na.ssl-images-amazon.com/images/I/61XYpkgWQ9L._SX679_.jpg

Update: MAF had oil residue on it.. Cleaned the MAF with CRC MAF cleaner and all is well now

OK, a simple question. I have a '14 CS with (just last weekend) 30k miles on it. Is there a recommendation for when to replace the AOS as part of some future maintenance to avoid a messy blow up (on-track or otherwise)?

I had the AOS fail in my 2006 Boxster Base while under CPO warranty. I had purchased at 54,000 miles and this was at around 60,000 miles. Even though "code free" when I picked it up, the Porsche Tech said go out and drive hard and if ANYTHING seems out of sorts, come right back. I went out and as I was passing 5000 RPM, power sagged and lost 2000 RPM. Drove back and new codes resulted in replacing downstream Oxygen sensors AND Catalytic converters (had to come from Germany). The oil poisons every sensor in the exhaust system to some degree. I drove mine 1.5 miles to the dealer from the point of failure and the oil measured at one bar when I stopped. Tech said I burned 2 Quarts during the drive. I drove the 2006 to 110,000 miles when I had a curb strike that took out right side wheels and did some undercarriage damage. Insurance company declared it "Not economically repairable" and valued it at $13,800 (due to high miles) I took the money and ran and now have a 2009 Boxster Base with 55,000 miles.

Anybody else replaced their AOS ? ... and at what mileage interval did you experience the failure?

08 CS - AOS failed just prior to 45k. Only warning sign was the dreaded screech as I was searching for a parking spot at a restaurant. I made the mistake of driving it home afterwards (about 10 miles). Just before my exit, as I let off the accelerator, she blew spectacularly. Towed it home and spent a few hours cleaning everything up and replacing the part. Pulled the plugs, cranked it a couple times to clear the oil out of the cylinder, put in new plugs, and got it all back together. Smoked like a chimney for a few miles. Ran like a top again after that. Great car!

Forgot to say... I agree with previous posts. Easy home job. Dirty but easy.

@desmotesta do you mind pointing us specifically to which hoses you replaced? Is that a recommended part of the job if it's being done prophylactically?

Hey losblancos. I did not replace any hoses, just the AOS itself. The biggest part of the job is the cleanup. You'll want to clean out the intake manifold for sure, but it really depends on how far the oil traveled once the membrane broke. I shut my engine off immediately upon failure, which may have saved me some work, but I'm not sure. The most important thing is that you clear the cylinders (passenger side) before you crank it. From what I read, you can bend a rod if not. Remove the plugs and crank it a few times. Oil will likely shoot out of one of the plug holes. It will smoke like crazy after you get it all back together... until the remaining oil is burned off.

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Replaced AOS at 152500 miles. Symptom was a check engine light. Luckily caught it early. Easy for me. Shop did the work. Base Cayman 2008.

There is another sub group of driver/owners that are at risk of destroying their AOS with oil slosh besides just the milage toll. Those drivers who are HPDE ing or Autocrossing using sticky tires . I oiled my AOS down a couple of times so I figured I was lucky enough to get through twice, I need a Porsche Motorsports 987 AOS . So, I had a few other items done to my car as well as replacing the AOS by Cantrell Motor Sports. One side note is the hoses do not match up to the Motorsports AOS , so be prepared to replace at least 1 hose a couple of years down the road. Oil impregnates the rubber water hose causing it to collapse due to the vacuum. Changing that hose is a $15.00 project. I have not found a Porsche part that will allow an GT3 /IDP Plenum to be attached to the Motorsports AOS . I wished I did, it would make my engine look better by removing the hose clamps. At any rate if you are pushing the g's with a 987.1 , then you should have at least an OEM AOS part in your tool box. I still have one along with the special hose clamp tool.