Sudden smoke on startup & check engine light

My car suddenly got heavy smoke on startup. My check engine light came on and the message center said to go to the nearest auto shop. All gauges normal. Coolant looks good & clean. What may be going on? Video here https://photos.app.goo.gl/3QZJQKMUqPbHTXG48

To me it looks like AOS failure allowing engine oil to be sucked into intake. Try not to start it again. Call your indy and have it towed for repair.

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I thought the AOS was slow, not sudden! Ah crap...

Sounds like your AOS has failed.. Search for threads key words " AOS + Manometer tests" to find out how to get the tools and do the tests, or drive to the local Porsche Specialist ..

Eliminate this problem forever...get the UAOS. Do not run your engine...it could hydrolock and throw a rod. Your engine is sucking in oil causing the smoke.

I have a listing in my spreadsheet that the "oil separator" was replaced about 13k ago. I'll check for the receipt to see if it was the AOS, is there another oil separator?

Just the one AOS. They either last or don't. Some have been bad right out of the box. If you are not going for the UAOS make sure your indy orders an OE Porsche AOS because Chinese knock offs are total crap. Plus, they are a real PITA to replace.

Oem AOS can last a long time or fail suddenly. Even if its in good shape and has NOT failed, it has a difficult time processing the oil if you filled your oil level to full or worse yet, over filled it. Nor can the oem AOS handle parking on a hill. Forget about higher g turns canyon carving or tracking. Besides doing a manometer test, all you have to do is start the car and try to take off the oil cap. If it's difficult to get it off from alot of suction and if it the engine starts to sputter and runs rough, there is a pretty good chance you have a failing AOS. as some of the guys mentioned, consider the UAOS with the track drain option, even if you don't track the car. It can handle overfilling the oil by 1 qt, maybe even 2 qts if you have a good blow-by test, but you can park it on a hill and canyon carve until you have had enough.

Ultimateaos.com They also sell it at Pelican. Replace your AOS with this and you won't have this issue again. Lots of us have done it.

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I need to spend more time at the message center.

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I don't think I got the message center option. Is there a PCCM+ version or retrofit for us '99 guys?

OK, I gotta ask since the concensus is most likely the AOS is going out on OP........ and I agree from following numerous threads that if it were me, I would replace mine with the UAOS, but nobody ever says which one? There is the UAOS-AL and the UAOS-E I am not super high-techy but it seems like the E has a prettier mounting system and a different warning light system? Again, I am not mechanically inclined so please use simple English for me, lol. Other than that, I don't know which one I would purchase if in his shoes (which I am sure I will be at some point). Maybe someone could point out the big difference for us non-mechanical (wish I was) speaking guys

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Exactly, I have this question also! I don't need flashy, I need functional. I'm thinking I'll order the UAOS-AL but it says it has everything "except aluminum relocation bracket". Do I need this? And why would they sell everything but... ?

All you guys have to do is PM Skip @Porschetech3

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I would consider the one with the track drain even if you don't track your car for the above reasons. It's the Swiss army knife of M96 parts.

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Buy the AL and at the bottom of the description on the LN Engineering page select track drain. It's $175. This will allow any excess oil to drain back into a modified filler tube that comes with the kit. I didn't get a relocation bracket. The track drain will also allow you to run over the previous oil limit without worry.

The UAOS-AL models and the UAOS-E models have the exact same performance and functionality ;; The cost difference come from the E-models start with base components that are name branded Porsche and Audi , then are hand-modified to be 4x more efficient and more robust by adding 2 solid copper mesh filters and a Laborinth inside the Accumulator and disabling the factory rubber diaphragm and adding one that is twice a thick Viton Rubber in a more convenient location...and of course hoses and priority accessories .. The AL models go through the exact same process and modifications, and they use exact same materials in the components ( PA66 35% GF ) but they are aftermarket and don't carry the name brand Porsche /Audi Tax, but are the most popular ... Both the UAOS-AL and UAOS E models can be optioned with the high mileage/Extreme Track Duty Auto Drain kit that makes them drain back to the sump 2x as fast as the factory or Motorsport units, and also makes them "maintenance free" . Draining back twice as fast has a huge advantage in the maximum oil level than can be used for Track Events, and of course the maintenance free aspect is nice for any car.. The UAOS is a complete Sytem and there is no down side, even the cost pays for itself in time if you keep the car...most cars have already had one , two, or three new AOS's installed already...

Thanks all for the explanation. That helps

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Thank you so much! Are there any other options other than LN Engineering or Ultimateaos.com to purchase this? They are on back order right now! I just spent 3 weeks without my car while replacing the suspension. Got it back on the road for a week only to have the AOS go out and now they are on backorder! I want to drive my car!!!!

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Your welcome !! UAOS sales will be off back-order soon as the CNC'd Aluminum Accumulators come from being Black Hard Anodized ... The back-order was due to supply/demand differences... The factory AOS system deficiencies have plagued the performance/dependability of the M96/7 engines for 20+ years and a lot of energy has been spent to accept/circumvent/work around these deficiencies that can effect the engine as a whole..it has taken some time for the word to get out about the new products, and has been catching on "the hard way" but is gaining speed every day as the proof is in the performance... The back-order list has gotten long, but I will be working to "catch-up" in the next couple of weeks ... Please be patient , the wait is worth it ..

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Can anything be done in the meantime to allow for shorter type rides with the car. Like disconnecting aos from intake and using some type of catch can setup...?

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Yep, I had to do this about 5 years ago when my AOS failed at Little Talladega right after the lunch break that caused me to look hard into the ventallation system and to invent/design the UAOS ...but first I need to get back home about an hour away.. The " Temporary Emergency Dirty Hack " was to just to disconnect the vent pipe at the intake and plug the intake, then leave the vent pipe "open to atmosphere to dump " ., this in theory reverts back to the "Old Road Draft Systems" that were used up untill the early 1960's ... it just dumps everything to atmosphere ..( not legal or EPA friendly) , and doesn't fix the problem just keeps from having a chain reaction of even more severe problems ..and you can even clean the Dirty Hack up a bit with filtering the dumped stuff or catching it in a " Catching Can " so it not so messy/oily or a fire hazard...and also upsets the fuel trim/AFR balance , So I don't recommend doing it .. Legal Disclaimer :: The aforementioned " Temporary Emergency Dirty Hack " is intended for "information only" and is not Legal or advised, the correct procedure is to have the vehicle towed to the destination...

So I went out to double check this morning before I hit the order button for a new UAOS. The oil cap test. My oil cap removed perfectly fine, no noticeable added resistance. However, there was a noticeable change in the idle when I took the cap off. Short of having that fancy oil cap vacuum tester, is there another way to test if the AOS is shot?

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Well, thats good... While the cap being suked down test does show you when the aos has more or less totally failed, there are degrees of failure that are not as obvious with that test. . By the time its obvious the cap is being suked down hard on to the filler tube, the vacuum leaking past the faulty AOS is way over max specs. If the aos diaphragm is only slightly torn the vacuum will not be so obvious at the cap, but enough to suk oil into the intake in many situations.... The only way to be sure is a manometer test less than 6 This is the one I have.There are better ones for sure but its sufficient for our purposes.... Drill a small hole in plastic cap a little smaller than the thread size on the fitting that comes with the meter. Start with small hole just big enough till the fitting screws in snug. Slide an o-ring up on the threads to the fittings shoulder, or wipe some silicone sealer on the top of the threads,. screw fitting snugly into the hole you made in the cap. Now start car let it idle and take a reading. Should be under 6, 4is even better. Go to autozone, advanced auto, etc, store and by a vacuum cap assortment to put over(seal) the fitting barb after you're done taking the reading and have removed the vac line. jmo

Allcool is right. Here is mine. I bought the manometer on Amazon for $100 around 3 years ago. Got a oil cap from the local porsche dealer and the plastic tube and brass bit from Ace hardware.

The vacuum in the crankcase ventilation system ( AKA AOS System ) is very very light , but is Sooooo important due to the Integrated Dry Sump system/flat six design.. For reference the specs is 4-6 inH20 ( inches of water ) ...in a perfect vacuum ( full vacuum ) there are over 400 inches of water , and the 4-6 inh20 is equal to less than 3/10ths of a PSI.... So no way to "feel" this , you have to use a very sensitive instrument or a "water tube" ( Old school scientific tool )

Allright... more questions... So, the UAOS is on 2-4 week backorder. I just went off of 3 weeks not being able to drive my car due to other repairs. I plan to own this car for a long time, and I am competent enough to DIY nearly any job on this car. So... Help me understand replacing the AOS with a stock one. Which one of these three is the proper air oil separator as there is a drastic price difference & appearance? If there is a dramatic price difference AND availability difference, I would consider replacing my AOS currently with a regular AOS. So I can get on the road and enjoy the very short convertible season here in Minnesota. I would then do the UAOS next time, in the future... These are all just thoughts for now, but it's how my brain works.

Or is this what I need? I'd strongly consider spending the $180 for this & doing it again in the distant future...

The Pelican part is what you are after.

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which one? That was my question.

Don't buy URO, go with the Porsche part or UAOS. I had a URO AOS fail at high rpm within a few months. Heavy on the gas and a huge smokescreen. I thought I had blown my new 4.0 up. Replaced with the Porsche AOS and back to spirited driving...

Even the genuine Porsche ones can fail in very short time. Pretty much a crap shoot. That is why the UAOS is so much better. The AOS unit diaphragm (the failure part) is disabled, with the actual new diaphragm being located near the throttle body, with a much longer lasting part. But when it does fail - it is a very simple replacement. If you don't have to use the car for daily usage, put it aside and wait for the UAOS. -Tom 2003 C2 with UAOS and UIDS (thanks Skip!)

As much as this goes against the wisdom of "fix it once and be done" by buying the UAOS. They are currently on back order for 4 weeks. I've already been mostly without my car for 4 weeks & I think I'm going to pull the trigger on the Porsche part today, and the UAOS in the future.

I get it. I go stir crazy when I don�t drive my 996.

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Not sure how much/many miles this month you need to drive your 996.? If its just for pleasure cruises, not long distances, maybe go for a temporary catch can set up for a month till your UAOS comes in. A catch can will prevent any further oil ingestion damage, but not be EPA friendly. Although probably still would pass a state pollution test. That type of open venting is all many old cars ever had to ventilate the crankcase. You probably don't want to change out your aos twice in a short period of time as its a bear of a job with engine in car. And all those hoses can be brittle and some are almost impossible to change with engine in car. Do it once. jmo

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Are there good links on this temp mod? The car is a daily driver for me. I'd happily do the catch can mod & wait. I heard that it changes air/fuel mixtures though and wasn't sure if it would cause other issues down the road.

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Not sure its appropriate for a daily driver for someone not familiar with this type of device. PT3 is the best one to ask this question. Maybe PT3 will chime in. Not sure the AFR changes enough to be out of range to be a real concern for a temp fix, ecu might even adapt sufficiently. Reason I suggested a catch can, hate to see you have to buy 2 AOS systems, and do 2 AOS/UAOS installs if not absolutely needed. I've read on the forum about a few guys running catch cans for years and even tracking car with catch cans.