What does white smoke mean? I watched a guy start up his 04 4S and a HUGE cloud of white smoke! lasted for about 10 seconds.

 

Persistent black smoke = rich fuel
Persistent white smoke = burning oil

 

In cold weather, water vapor.

 

Bad AOS.

 

Pretty normal for a 911. As long as it clears up quick, just means it's burning a little oil at startup. Perfectly normal.

 

I have never had or seen a 10 second cloud of white smoke coming from any Porsche that I would consider this normal. A little on start up yes I agree is normal.

 

Close...

Black Smoke - Rich Fuel
Blue Smoke - Burning Oil
While Smoke - Burning water - either water vapour (if just a few seconds) or problem with head gasket (very bad)

 

+1 Persistent white smoke is a problem (head gasket or worse - intermix, cylinder head, etc)

10 seconds is a *little* long. I would be i) checking the AOS as others have said, and ii) looking for signs of coolant in the engine oil.

If it isn't consistent, I wouldn't worry too much. I have heard from others that if you run your car really hard, you may see an abnormally large amount of white smoke upon the next cold startup.

 

Seen this on more than one 996, especially if vehicle is parked soon after some high speed, hard right turns.
I remember that first time I saw it, I swear my heart stopped, and I got a few more grey hairs. Some guy on renntech had some excellent explanation, but long story short: no big deal.

 

I just had this too, freaked me out, and also my GF even mentioned OMG..( it had to be alot for her to notice LOL).

Posted here and searched saw same responses, so I decided to run the HELL outa the car, what an excuse to do it! Drove it super hard, started next morning and seemed normal , no smoke for now at least so I'm ok..keep an eye out though!

 

Aos x2

 

Did you just change the oil? maybe just overfilled a tad! no big deal..got it twice after changing my oil then it went away

 

Had it on a couple of occasions that I ran the car hard and turned it off too soon and next day started it up. My dealer said it was normal.

Now if I do some hard driving, I let it idle for a minute before I shut off the engine. I haven't seen it happen again. I think Porsche sells a racing AOS that fixes it.

 

After a hard drive on tight turns i turned on my car and saw some white smoke on start up which disappeared after 15-20 sec. Is that normal?

 

Yes it could be perfectly normal, especially if it was just condensation (water vapor).

In addition, one thing you can do to reduce that is to let the car sit for a minute or two at idle after a hard drive before you shut it off, let the vacuum and AOS get a chance to leak down.