How to TEST THE AOS on your Porsche before you replace it!

Stacked cars - low key (awesome) flex

This almost needs to be the type of tool you rent out to people for $25 shipped with the cap for your specific vehicle. While I want to do this, $70-$80 for a tool I'd use once, maybe twice, makes me shy away from it. Maybe I can take up some HVAC work or try to balance/sync carbs on a bike/car one day. Great video!

Every time you post a video whatever it’s on breaks, starter is going out on my 986 and you just posted a video, now I need new coils and plugs and boom you posted the video. Guess who now has alittle white smoke on startup

Good stuff. Does a 986.2 Boxster S use spark tubes?

I’m a little confused by the conclusion - according to the measuring tool the AOS is ok but the car is clearly smoking. Does this mean the issue is elsewhere? 😎

Replaced the AOS on the 986 a couple weeks ago, even though it had been done by the previous owner just a couple years ago. Once I got into it, I notice the lower bellows weren't seated. At that point I already had the topside disconnected so I put the new one in, but I suspect the old one was still ok. I wasn't getting a ton of smoke, but the motor was damp around the secondary oil pump and burning off on the new Fabspeed exhaust. Unfortunately I had already replaced the o-ring on that oil pump over the winter too, but oh well. And now that all this is done...I just found a 987.2! I'm going to fly down south on Friday to pick it up and drive back to Chicago. S model with PDK (had a slight preference for manual), Sport Chrono Plus, and a secret under the back--a Capristo exhaust. :)

During the IMS Solution certification my AOS was replaced because it measured -6.09.
I believe the range is -4 to -6 so I agree that it looks like yours is ok.
But…..I’d still replace it and eliminate it as the cause of the smoke 🤷‍♂️

Another good video dude. Keep up the good work!

Hi friend. The video is awesome. Would you like to try our Boslla 6500K led headlight bulb? We wanna send it for you to try. I have contacted you on Ins dm. Hope to hear from you, thanks.

I have the same unit. It comes with instructions. If you press the HOLD button for more than 2 seconds, it will ZERO the reading.

Cool video - thanks for going through this, by chance did you happen to remove a/the known good oil cap from the car while the car is running? I read/watched video that said that can be a tell tell sign. On my 987.2 CS when I do this it will "suck" the cap back down, making me think I have a failed AOS and am seeing excess crankcase vacuum. Also, see you are in NC, saying hi from SC!

Finally got around to doing this today. Pulling a 4.12 steady. Is that good? Thanks man for all the great videos!

Great video and very helpful! I tried this today as I have no record of my AOS ever being replaced on my 1998 2.5 Boxster. My reading seems to be bang on but when I rev the car hard, the reading on the manometer can momentarily fall to close to zero when I let the pedal off and the revs are falling. Is this normal? When revving hard the reading goes just above 6, its the return to idle where I have this momentary low reading...Thanks!

Can valve covers be resealed on a 2000 Porsche 911 cerrara without dropping engine ?

I’ve had three fail in seven years. Each time trashing my intake with oil.

So what caused the smoke

Nice video. I must get this bit of kit

How about the oil gauge indicator on the instrument cluster! Mine shows at startup but I don’t see the usual elevated indicator as to oil level! Yes, dipstick checks out full but I don’t see my reading. Can you check this Aaron. I could use some DIY feedback! By the way, this occurred only after I replaced a dead battery and installed a new battery, belt, and alternator.

Can't tell you how many weird issues cleared up after swapping the AOS, it's something I'd do again and recommend to anyone considering a Box or Cayman.

Just a note on this for people referring to this video for help.

You said on a more recent video that you should have the manometer running before you actually start the engine, and get someone to watch for a spike in pressure during engine startup, as sometimes the AOS problem only spikes the pressure on startup and then it falls back in spec once the engine is idling.
Thanks for all the videos.

Really cool test. Kind of confusing. My 911 did the same thing so I replaced it with a Porsche motorsports problem solved.

I'm piling up a list of things to do LOL and almost every single item you've already made a video, ha!

I don't see any white smoke on start but I just did noticed a rather high-pitch noise (not very loud but I'm super sensitive to noises...) only upon deceleration today which led me to look up things and it's possibly an AOS issue. I believe mine was replaced by previous owner at ~100k on 2018. Currently at ~122k, do they fail that often??


Which area of NC are you in? If close by maybe I can borrow that special cap in exchange for some beer or coffee :D

So why the smoke on start up?

So initially you weren't getting any readings, then you pressed the temp button and you started to get some readings. So is the process to press the temp button after start up to get a reading? I'm not clear on the process you did.

Getting 12 and up at warm idle, I guess it’s toast

Thanks for the video
I read 4.18 on a 997.1
I'm guessing is bad
Any thoughts?

Another great Porsche video. Thank you.