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New to me my 996.2 has a smoking issue. Here's the timeline
* June buy the car. PPI notes oil leak possible from RMS.
* drive it for a few 100km and note that on heavy acceleration there's smoke from the rear. Stop the car, let it sit, and most restarts the car was smoking for a few seconds and then stopped.
* 3rd July - Took it to known porsche indie. Leak identified (from the IMS Solution cover plate). They did all the usual tests (???) and said AOS doesn't fail any of the tests
* Approve gearbox out and fix the leak. New clutch/DMF at the same time. I also asked if it was easier to replace the AOS whilst the box was out and it would save me $300 in time. so replace AOS
* They open the AOS and there's a tiny hole that they think was probably the issue
* July 10 to Aug 10 - Not a wiff / sign / nothing of smoke. Including 250km of hard (2nd/3rd) in/around some twisties.
* zero oil consumption that I can see
* yesterday drove 70km on the freeway. A copy of wide open throttle in 3rd (love the noise) . all good
* last night drove to the shops for groceries. Car was warm, oil pressure at idle around 1.5. Turned onto a little 'strip' where I can give it a little beans. 2nd to 80kph - rear full of smoke.
* got home parked it for two hours. Started it... smoke... (i'll see if I can attach a video somehow.
I've called the indie and they're talking about pulling intakes out, spark plugs to scope the engine etc.... The car did have some sort of engine refesh from the previous owner. Threw lots of $$$ at it. and the engine is only 5000km old....
They're not even questioning the AOS. Said 'they've never seen a new one fail that quickly'
Last edited by justinbAUS; 08-11-2024 at 09:54 PM.
Not saying this is your problem, as I'm not there and internet diagnosis is problematic for sure,,, but....
Brand new AOS have and do fail as reported on this forum, and its not uncommon especially for cheap after market ones.
You can disconnect the aos line at the throttle body and plug throttle body port off with a vacuum cap from any auto parts store. Leave aos line open, wrap end of line with rag and insert in plastic baggy tied off lose with a tie or something so line can breath a little but not drip out oil on engine. Shouldn't be much oil coming out with no vacuum on it any more. Secure the line so it doesn't get caught up in belt or melted on exhaust. Run/idle/drive engine easy till it clears out. Probably some residual oil left in intake that will need to clear out to fully stop all smoke.
If smoke stops it most certainly is the aos again.
Below is a picture of what @De Jeeper is describing. You can find the parts on Amazon. Oil cap can be found at your local porsche dealer. The oem aos can last for a good long time and it can fail quickly as well.
The big problem with the oem AOS is that it struggles to process the oil regardless of whether the diaphram fails or not. So if you are running the oil level at or near full, it will most likely smoke. Especially under heavy acceleration and cornering. Same can be said for parking the car on a hill. You will most likely experience smoking problems.
As mentioned, if you want to eliminate the smoking, failure risk and hydralock risk, go with the UAOS track version. It can handle up to an extra quart or two of oil above full without a problem. What this means is you never have to worry about over filling it, parking on a hill or under heavy acceleration and high G turns. Plus the diaphram is 2x the thickness of the factory AOS. Just an all around better part than the factory aos.
It tokes about 10 seconds to test the crank case pressure with a manometer and an old oil cap with a barbed fitting. Anything over 6 inhg and its bad.
On this side if the pond there has been a UAOS developed and its worth installing if u can. Just do a search here for details.
While I agree DJ, and the UAOS is most certainly the way to go, many 996 owners don't have a manometer and cap with fitting. Or have the desire/time to get the stuff and do the test. Meanwhile....
Thing is many with bad aos continue to drive wondering whats wrong, not knowing what can happen. if they are going to continue to drive the car to the shop or where ever, best to have a faulty aos disconnected asap imo. And pulling that line will do it quick and easy. don't even have to pull the airbox. Might prevent a hydro-lock or partial hydrolock if it hasn't already happened...
Below is a picture of what @De Jeeper is describing. You can find the parts on Amazon. Oil cap can be found at your local porsche dealer. The oem aos can last for a good long time and it can fail quickly as well.
The big problem with the oem AOS is that it struggles to process the oil regardless of whether the diaphram fails or not. So if you are running the oil level at or near full, it will most likely smoke. Especially under heavy acceleration and cornering. Same can be said for parking the car on a hill. You will most likely experience smoking problems.
As mentioned, if you want to eliminate the smoking, failure risk and hydralock risk, go with the UAOS track version. It can handle up to an extra quart or two of oil above full without a problem. What this means is you never have to worry about over filling it, parking on a hill or under heavy acceleration and high G turns. Plus the diaphram is 2x the thickness of the factory AOS. Just an all around better part than the factory aos.
Thanks - Yea I don't have one of those but I could, as a test, pull the line off the throttle body and plug the hole with my finger and get wife to start the car. (or see if that pipe dripping with oil)
While I agree DJ, and the UAOS is most certainly the way to go, many 996 owners don't have a manometer and cap with fitting. Or have the desire/time to get the stuff and do the test. Meanwhile....
Thing is many with bad aos continue to drive wondering whats wrong, not knowing what can happen. if they are going to continue to drive the car to the shop or where ever, best to have a faulty aos disconnected asap imo. And pulling that line will do it quick and easy. don't even have to pull the airbox. Might prevent a hydro-lock or partial hydrolock if it hasn't already happened...
jmo
No one in Australia sells the UAOS from what I can tell. I can see it is a smart system.
I've called the indie and they're talking about pulling intakes out, spark plugs to scope the engine etc.... The car did have some sort of engine refesh from the previous owner. Threw lots of $$$ at it. and the engine is only 5000km old....
They're not even questioning the AOS. Said 'they've never seen a new one fail that quickly'
Originally Posted by allcool
While I agree DJ, and the UAOS is most certainly the way to go, many 996 owners don't have a manometer and cap with fitting. Or have the desire/time to get the stuff and do the test. Meanwhile....
jmo
Doing the simple test was mainly in responce to his comment about his indy not thinking it was the new aos. If the indy put the factory or oem aos in the part should be under warrentee and it should be repaired for free. If he used a cheaper aftermarket unit in then shame on him and it should still be done for free. Unless i misunderstood and the indy did not do the install?
Doing the simple test was mainly in responce to his comment about his indy not thinking it was the new aos. If the indy put the factory or oem aos in the part should be under warrentee and it should be repaired for free. If he used a cheaper aftermarket unit in then shame on him and it should still be done for free. Unless i misunderstood and the indy did not do the install?
The indie did do the AOS about a month ago.
On the phone they started talking about taking intakes off, camera in cylinders etc.. I'm trying not to think the engine's has something catestrophic.
Last edited by justinbAUS; 08-12-2024 at 08:01 AM.
Justin, I wouldn't loose any sleep over it. It's an extremely common occurance and an easy fix.
You have 3 choices to fix it (AOS) in order of worst to best from my 22 years of experience owning my 996.2 and experiencing AOS failures on the street and track many times.
1. Replace the factory AOS with another one.
2. Replace the factory AOS with the Porsche Motorsports AOS
3. Replace the factory AOS with the UAOS track version.
I don't know a thing about international shipping, tarrifs and emissions restrictions from the US to other countries, but at the very least, if you can't get the UAOS in your country, I would then replace the oem AOS with the second best option which is the Porsche Motorsports AOS because it can process the oil much better than the oem AOS.
However, if you want the best solution, put the UAOS with the track extension on your 996 if you can import it into your country. It's the Swiss Army Knife of AOS solutions with a laundry list of advantages over the oem AOS and Pprsche Motorsports AOS. Even if you don't track your car, go with the UAOS track version because of its functionality.
Factory AOS have been known to fail out of the box, as others have said. The genius behind the UAOS - @Porschetech3 - is a member of this forum, you can ask him nicely if he'll ship to Australia.
I'm guessing they want to look in the intake plenum to see if there is oil and any other debris in there - you could also drop the sump / cut open the oil filter to check for any debris in the oil, doing a fresh oil filter change as part of the operation. Install the LN Engineering magnetic drain plug at the same time. That should cost less than re-doing the AOS at the outset and will ease your mind as to what is going on, or give you very bad news but at least you know where you are.
08-11-2024, 09:52 PM
AOS - Failure after 500km? (300mi)
