My GTS has 7K on the clock and does this about once per week, so I am hoping it's nothing sinister!

White cloud rather than blue indicates not oil but water.

What was the weather like?

Hmm... yes mine is more blue than white, which I understand is fairly normal.

I get a little white under normal conditions, which I put down to condensation in the exhaust, but not huge amounts as you described.

I'm crossing my fingers and tieing a knot in a few things too...

996 turbo here. Bit of blue smoke on start up roughly one in ten starts. It's nothing to worry about.

If the journey is short and/or the car has been standing overnight on a humid night, then there may have been condensation in the silencers that materialized as a white cloud on the next start.

In spite of the white color I suspect the cloud of smoke was oil smoke.

If if was water vapor the cloud dissipates very quickly even if there is no wind/breeze.

Oil smoke hangs together as the cloud drifts downwind.

Given the circumstances of the car's usage before you parked it up, I'm guessing the smoke was oil smoke and this is normal.

Even new Porsches emit oil smoke upon startup and the techs tell me that all they do is observe that the smoking is short lived, observe if the engine is otherwise acting up, running abnormally rough, or if the CEL is flashing or even solid on, and absent any signs of distress pay the smoking no mind.

The hard running you engaged in I strongly suspect puts a lot of oil in the intake system, make that on the intake system's inner walls.

This oil comes from an AOS that is lousy at separating the oil vapor from the fumes it passes to the intake.

Upon engine shut off this oil on the intake manifold walls drains down and gathers in one or two cylinders and upon the next engine start clouds of oil smoke billow forth.

(Techs tell me that almost every engine that comes in that if they have an opportunity to inspect the intake manifold find the walls damp/even wet with oil.)

My usual advice to cut down on the smoking chances is to use a proper oil, make sure the oil is not too old, that is has too many miles on it from which is gets thinned out by water and unburned gasoline, and the engine is not overfilled with oil.

If you can before you shut off the engine give it a moment of idle time. However, if you have been running the engine particularly hard this may not be enough to see all the oil deposited on the intake walls drawn into the engine and burned.

A really hard run should see the car driven a few minutes at moderate speeds and engine loads to shed the heat load that hard running creates -- which is important enough to mention it first -- and to give any oil time to pass from the intake to the engine and be burned.

Even if you do the above -- based on my experience doing the above -- the engine will smoke upon occasion. The culprit? The AOS just sucks in removing oil vapor from the crankcase fumes.

Sincerely,

Rockster.

They all do it, can be a bit embarrassing, but it is normal. Made worse by, for example,starting car, moving it off drive, switching off and leaving,the next time you start it there will be so much smoke you would think that engine was a two stroke!.

Same here: http://www.pistonheads.com/gassing/topic.asp?h=0&a...