White smoke after hard drive

So I was doing a track session at Fuji Speedway, and an odd thing happened. About two laps in, I was coming out of one of the last corners, and while hard in a corner, I looked up into the rearview mirror, and saw a cloud of white smoke behind me. I obviously immediately panicked and checked gauges: no overheating, no warning lights, nothing. Fine. I pitted and observed the following: 1) At idle, no smoke. 2) I revved the engine a few times while parked: puffs of smoke. Somewhat raspier sound than usual. Seemed a bit louder than usual, too. 3) I stuck my face into the right exhaust pipe for a minute or so: when idling, it was emitting whiffs of white smoke, which seemed like leftovers from the incident before. Not left exhaust, though. I figured the session is hopelessly wasted, so I set about figuring out what's wrong. 1) Nothing in the engine bay that looks suspicious - no leaks, no liquid, nothing on the ground. 2) Nothing in a Durametric scan: all modules are clean, no faults logged. 3) Car runs fine. No rough idle, nothing. I packed up my stuff and drove home; leaving the track, I revved it towards the limiter in first/second gear (Tiptronic) and sure enough, some smoke came out once again. But as I got on the highway and accelerated as hard as I could, it no longer happened. In fact, I was no longer able to reproduce it at all in the subsequent hours of driving. However, it seemed pretty repeatable on the track (it happened in fourth to last corner, and as I came into the pits, accelerating out of each corner caused the white smoke). I thought maybe it's the air/oil separator, because I feel like previously I heard a certain repetitive "sucking" sound when idle, which seems to be gone now (so the diaphragm ripped?), but I'm not sure if the symptoms are right - idle is fine, and I tried removing the oil cap when idle - there's a vacuum in there, but it's quite easily removed (and I don't have a "good" 911 to compare to, so I'm not sure whether there's supposed to be NO vacuum at all, or what). Oil level, btw, is around 3 bars under full when cold and oil has had time to settle. What should I try to diagnose? My mechanic here charges $150/hour, so I would really, really like for it to just go away. Did I overfill the oil and did it spill somewhere in a hard corner? Or is it more sinister?

the more you post, the more I am convinced you have a scored cyl. get the cylinders scoped. your posts sound eerily familiar to mine before I did my rebuild. white smoke after track runs was also a symptom my car displayed while I had scored cyl 4 & 6.

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Crap. Really? I guess I was somewhat hoping it wouldn't be that because that seems like an expensive as hell fix (not to mention just the check alone is going to be $300). I was hoping scored cylinders would be something more easily repeatable but you're saying you had smoke as well? Damn. Okay ... I guess I'm going to have to bite the bullet and get that done finally. For my own knowledge, should I have still tracked today or did I do the right thing abandoning the track day? It sounds like you kept tracking regardless?

here's mine on cold start up. this happened once in a while on startup. wasn't consistent at all. https://youtu.be/YSRTKH89MdM

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depends on who you ask. I kept tracking my car, even with scored cylinders. damage was already done. I just added oil. Jake was adamant I stop driving the car right away. quite a few here just add oil and keep driving.

Is there any reason that you couldn't borescope it yourself with one of these $10 borescopes? I have one and it works very well. Haven't ever tried to borescope an engine with it, but seems like it would work. http://www.ebay.com/itm/282172411847?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

you can use a scope once you remove the sump plate also. less labor than removing and checking through spark plug hole. more access/view removing the sump plate also....

This sounds like the common AOS behavior I've read about from tracking or really hard cornering repeatedly.

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yes, I hope I am wrong and it's just a bad AOS. but with the other threads he has....I'm not convinced

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I agree with this. It may just be the AOS got overwhelmed, particularly with sweeping right handers. The oil swings over to the left side of the engine and into the AOS, then overwhelms the intake producing smoke. Without a deep sump and proper baffles this is a typical track day outcome. I say monitor your oil level, listen to the engine for any strange noises, and probably plan on AOS replacement. If the diaphragm blows in the AOS, coolant will get pumped into the intake and engine cylinders.

I wouldn't immediately jump to the scored cylinder conclusion without first checking the AOS. Are you consuming oil during normal/non-track use? My car will smoke on startup after extreme (for me) track use unless I let the car properly cool down after each session. I set my watch and either drive around the track or let it idle for 10 minutes. The AOS is simple to test with a cheap digital manometer. I always recommend to eliminate normal wear items (AOS in this case) from consideration first before you go removing spark plugs or your sump. If the AOS is fine, then you can begin further analysis.

You guys need to keep in mind his other threads about ticking/knocking. Combine all these symptoms and well... I hope I am wrong. Its such a ****ty feeling finding that out. A quick boroscope will alleviate (or confirm) the fears.

Sounds like you overwhelmed the oiling system. Give it a couple of days of normal usage before you blow any money on it. The oil system in the stock 996 was not designed to handle track use--no matter what anyone on here says.

I didn't realize this was the ticking car. You are tracking a car that you may have other issues with, a scored cylinder, weak tensioners, a sticky lifter, who knows you don't have time to check it out. It isn't your oil level or your oil pressure. Something is marginal in your valve train or cylinders (or like Schnell mentioned it may even be an exhaust leak). I think the best response is that either your engine is going to blow or it isn't. You don't care so why should we? The immediate problem in this thread is fairly normal for tracking a street 996. DBJoe summed up the problem nicely. All previous Porsches were designed to be "race-track ready" street cars. Not the 996 or its progeny. That was why they built a different engine for the Turbo/GT2/GT3. Your car will probably keep running for a long time but sound, smell and pollute more and more like a cheap two-stroke weed wacker after each "hard run". Enjoy it while it lasts, or quit the nonsense and have a mechanic look it over.

sorry, I don't buy this the porsche 996 isn't to be tracked. I see 3.4/3.6 Porsches at the track, just as much as miatas and these are regulars...beaten to hell and they keep going. hell, Ive done about 6 hours of racing on severely scored cylinders. Oil consumption was great of compared to daily driving. car pulled really strong too.

Overfilled oil causes this symptom as well. Make sure you are one bar below full for track driving. -td

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You may not buy it but it is true. It is also true that these are good tough engines but if you track it without modifications it will smoke, and tick and burp and smell bad. Doesn't mean you can't do it but then why bother asking why it's doing these things? It is doing them because the stock 996 is a street car. Period. Don't want to take my word for it? Here is a quote from Fritz Bezner in the May 2016 issue of Panorama "The development of the 996 Turbo had one overriding objective: We had to find a way to make an engine that would be appropriate for GT racing and customer sport. The M96 was not suitable. ..." They also make a Motorsport AOS. Last time I checked, motorsport had something to do with racing... Don't get me wrong, the car has great bones and is great on a track but if you track it without the mods most street cars require, don't expect it to be a garage-queen-quality DD the rest of the week. Racing is an expensive sport no matter what you paid for admission. EDIT: The 3.4 and 3.6 should not be lumped together. The X51 and Motorsport AOS coupled with an X74 suspension is a suitable track car. In the US, this is possible on a 3.6 but the X51 is not compatible with US (SAI) 3.4 M96s.

I feel like I'm causing some emotions to run wild. Which is good for discussion, I suppose. First off, I don't "not care"; that said, I'm trying to avoid brain surgery if it's normal to have headaches due to sun exposure, so to say. The comment about overwhelming the oil sump does play to what I thought; as for the clicking, I keep saying that after I added oil, it basically stopped. Of course, AWDGuy's experience with it *not* being consistent makes me wonder if I'm being overly optimistic just simply because it stopped. The other thing is, and this might sound overly cheap on my part, at the hourly rates the mechanics charge here, I'd at least like to get a theory or two going before I write a blank cheque - and the conversations are going in three separate directions here now (AOS, scored cylinders and "****ty engine design so leave it"). With all of that said, though, I don't think I've ever seen a 996 smoke up like mine did yesterday - even if it only happened once. I can't imagine I'm the only one to EVER have a bit too much oil on the system so I guess I'd better go start the blank cheque writing (also, I'm cornering myself by saying my clicking issue was solved with more oil, but my smoking might be due to too much oil). Also: with all due respect, I don't buy the "996 sucks for the track" argument: while I feel like that might be valid for stripping the interior and going for lap times, I don't think it's valid for an idiot like me trying to push his DD to the limit. Okay, maybe I'm selling myself a little bit short here, but nevertheless, it's not like I'm a pro racer. My last track cars were turbo BMWs, which pulled like freight wagons when they weren't in limp mode with a cacophony of warning lights on the dash, and a Golf R that just simply ate up laps like a hungry hippo. I've never had issues like I'm having here, so do bear with me.

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Pseudo Nim, this is just part of normal RL banter. When the 996 was designed there were two things that really upset the 911 crowd. The first was water cooling and the second was the "integrated dry sump". I think they could eventually accept the water cooling but the transition to a wet sump was a huge, and I think tragic, change. Porsche had always bragged that their road cars could be driven to the track and raced. Not so with the M96, and they knew it. That is why they built the Mezger engines, which are still dry sump, for the Turbo/GT2/GT3 and Cup cars which was not a cheap development. If you look at the X51 kit it has different pistons, heads and some porting which give it more power but most of the changes are to the oil system. There is nothing cheap about wanting to be an informed consumer. If the ticking is really gone, I stand by my first comment. Leave it alone, it will go away. Most guys seem to feel that mid-indicator (or down about .8 quarts) on the dipstick is about right for saving the AOS on the track. Don't know why it works but it seems to. A deep sump with better baffles will help and lowering the oil level seems to help save the AOS. If you have a US spec 3.4 (or any M96/04) not much you can do for the oil passages but the 3.6 accepts all of the X51 parts and I believe many of the oil passage updates are part of the base engine.

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Gotcha. I have an EU spec 3.4, 2001 MY, so I'm pretty certain that in light of that, there's nothing I can do. That's very interesting. That'd be the first car I owned that "can't" go on the track. That would be quite disappointing. I think I should still boroscope the cylinders to make sure AWDGuy's doomsday talk is unjustified (I passionately want him to be wrong, heh). And then... .... then what? My current oil at cold is about 2 bars below max, which seems to prevent clicking. My mechanic actually suggested switching to 15W50 to prevent clicking, and then I'd infer of my own logic that I'd run a bit less (say, around 8 qts rather than the usual 8.4) to prevent overfill? That seems like a really hacked together solution, though. Seeing as switching to a Turbo is currently not an option, is there anything I can do, assuming nothing is wrong and it's just bad design? Or do I drive around puffing smoke? If I understand correctly: assuming it's ultimately a "leave it" solution, after a few hard corners and the oil spilling around for a bit, it should "level off" to a point where my cornering speed will exceed the spillage? At which point the puffing will stop? (so as long as the track marshals don't kick me out, I should be good?)

Pseudo, I would not go as far as to say don't track it. Just be aware of its inherent weaknesses. Run it down on oil like most of the guys that track regularly suggest (helps not blowing the AOS), maybe add a deep sump and X51 style baffles. As for oil, BIG topic here, I'll only say that the local PCA Tech Inspector suggested 5w 50 to me, track and street. I run it all the time. I used 15w 50 once, put in by an old air-cooled Porsche guy that did some work on my car and I changed it within a week. Just never felt "right". Maybe someone can chip in whether the upgraded oil pump like the X51 uses fits or not. Don't know what else guys are doing. These are great cars on the track. Have fun with it but beef up the oil system as much as you can. If you think you may still have the tick then you should have it checked but truthfully many guys run for years with scored cylinders but it will smoke and make noise so you may get the new guy at valet parking (if he can drive a stick).

If the smoke appears only during left hand corners then it's your AOS. There is a motorsports AOS that can be fitted (big $$$ tho).

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Nah I'm not planning to make this into a track car after everything I've read ... hehehe. But if that diagnosis is correct (and yes, it was a left corner) then replacing the AOS would get me a few more thousand miles out of the car? (and not smoke up during basic track days)

Keeping the oil level at about midway between the upper and lower marks on the DIPSTICK will help. Don't trust the electronic gauge. You may or may not need an AOS replacement, they are known to pass some oil into the engine under high lateral accelerations. The biggest cost of a new AOS is the labour cost (unless you are a DIY type of guy).

I have a standard AOS and R-Comp tires and have never had any white smoke on the track. I do make sure that my dipstick is exactly at mid level though. With an X51 baffle and a good race oil these cars are absolutely solid on the track. For racing, an acusump is a fairly inexpesnisve way to solve the oiling problem. These cars are actually much cheaper to race than Gt3's or Cup Cars. And much much cheaper than the Turbos which really aren't meant to be raced.