White Smoke... What's wrong?

[2000986s]

Hey guys,

About a month ago, I was having some fun driving my 2000 s hard. I was in 4th gear at ablut 5k rpms, shifted into 5th and started blowing white smoke out the exhaust. Pulled over, turned car off, let cool down, re started, more smoke, then smoke cleared and car ran fine after that. Blew a little smoke on a cold start the morning after, but then nothing. No CEL, no weird sounds, no bad start ups, no smells, totally fine. I did some research and everything seemed to point to my oil air separator. Well I was about to replace my IMS anyways so I went ahead with that and had my mechanic check everything out at the same time just in case. He said the separator looked totally fine and nothing else seemed to be wrong with the car and it wasnt coding anything. Fast forward three weeks to yesterday. Again, I was driving my car hard. I was at almost 6k rpms in third having some fun with a 350z, shifted fourth then quickly into fifth and again blew white smoke. However this time it went away right away until I turned the car off an hour later and started it up again, when it again blew white smoke just temporarily as if it was ridding itself of it. Now its running totally fine again, no weird sounds or codes or anything. Is something wrong with my car? Am i causing any damage by driving it daily still? I'm not going to drive hard very often but it's still nice to know that I could if I wanted to.

Thanks in advance!

[CrisZenithBlue]

they say its normal for these engines to smoke sometimes on a cold start up. it could be caused by an oil overfill or maybe an AOS not doing it's job properly, catching all the extra oil that would end up in the intake.

the only two times when my car blew white smoke was when it was overfilled in which case i pulled the oil filter housing removing some oil and it never did it again. and i drive it hard every single day unless its raining. if you have too much oil it will also ruin your AOS in time.

i'd start looking into that first, i dont know if you do the work on the car but too many mechanics overfill these cars setting you up for trouble down the road.

one way to check if the AOS is still good is remove the oil cap with the engine running. if the vacuum is really strong that it takes a bit of force to pull the cap up then you might have a bad AOS. if it's easy to lift then you're fine.


i'm sure you'll get more help on here.
good luck with it!

[2000986s]

I'll try that oil cap test today after work, thanks for the tip!

[Porsche9]

Like Cris said check the AOS. Until you determined the cause you should stop driving the car as by doing so you are risking damaging the engine.

[CrisZenithBlue]

check your oil level as well and see where it's at.

overfilling causes premature failure of AOS which can cause a lot of oil ending up in the intake and in a cylinder finishing in hydro lock and then you need a new engine.

whenever i have to leave my car with someone, no matter who they are i dont trust and always check all levels again.

TRUST NO ONE!!!

ok maybe i watched X Files too much (the old series)

[2000986s]

Damn! Yeah definitely don't need to fall down that slippery slope.... I'll check on both things after work today and post a reply with my findings.

Thanks again!

[mikebox]

Could be oil passing the piston rings. Oil separator is normally the issue tbh I have a fair few of these come through my garage (in the UK we tune and repair porsche)

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[Tcar]

Any oil in coolant?

Any coolant in oil? Mayonaise stuff?

[mikebox]

Chris the truth is out there lololol

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[CrisZenithBlue]

I want to believe! :d

[2000986s]

Alright update: oil levels are perfect, no suction when taking the oil cap off while engine is running so AOS doesn't seem to be bad either. No coolant in oil or vice versa. Car is still running fine, however when I am in neautral at a stoplight, the engine tends to do little fluctuations where it'll rev from about 500 rpms to 1,000 rpms. It literally sounds like I'm blipping the throttle and some douche in a civic actually thought I was trying to race him lol does this sound like an additional symptom to my white smoke issue? Pretty soon I'm probably just going to take it to my mechanic but I really don't wanna pay the labor if it's something small and stupid.

[BoxsterSteve]

Fluctuating idle could be due to a dirty throttle body (mine did this) or a vacuum leak.

[stelan]

I think AOS, does not necessarily will be evident or blowing smoke all the time but it is probably dying

[fatmike]

White smoke = New Pope?

/

[nieuwhzn]

AOS starting to fail, fouling up the throttle body and MAF which is causing the idle fluctuations. AOS is cheap, putting it in is a pita.

[2000986s]

Besides suction on the oil cap, are there any other ways to diagnose a bad AOS? Or should I just take it to my mechanic and tell him to check it out and let me know if I need a new one? I am not very mechanically inclined (though I'm trying to change that) so I am incapable of doing most of the work on my car:/

[CrisZenithBlue]

not sure of any other way to diagnose the AOS but the guys are right, when it starts to fail the diaphragm inside goes bad creating a vacuum leak and allowing oil to end up in the throttle body. both of those things can cause your idle issues.

think of it like this.. the AOS is a maintenance part, it normally goes bad after 60,000 miles. if you dont have a record of it being changed recently i suggest you do it as preventive maintenance which is never a bad thing on these cars, just like the water pump. an AOS is around 150$ get the part online (i recommend warehouse33auto.com, put rennlist in the cupon field for an additional 10% off, doesnt get cheaper than that), you get that to your mechanic and tell him to also clean your throttle body, check the MAF and give it a good spray down with MAF cleaner and you're doing a good thing for your car which will most likely solve your issue as well. it will run better and allow you to feel confident driving it hard.

[CrisZenithBlue]

my bad.. a genuine porsche AOS with the discount is literally 100$. dont go for the cheaper ones at 60$, it's not worth the hassle if it comes bad which does happen.

[2000986s]

Thanks for the amazing info and discount Chris, I will be moving forward with that and hopefully is solves my issue. I just invested a good chunk of money in doing my IMS. Another 100$ of preventative maintenance is nothing compared to that. Thanks again everyone I really appreciate it

[FauxDiablo]

Originally Posted by CrisZenithBlue

I want to believe! :d