C300Sport

I have had contractors working on the house for the last few weeks. With all the trucks and people coming and going, I have had lots for start ups where the car is only running 30 secs or so while I move in/out of the driveway, etc, etc. I have noticed puffs of smoke on start up, but only after I have had a couple of those short starts during the day.
Is this simply unburnt fuel in the cylinders or is it something more sinister?? I am assuming the cold starts have something to do with it but wanted to see what you guys think. Could it be an early sign of something worse to come...

joshg1001

completely normal and happens to all cars. should disapear after the engine warms up

451/443=EW

Yes to me it sounds like unburnt fuel due to a start up and quick turn off. I suspect it wont happen when you start to drive it normally again. Take it for a run and see what happens the next day.

JFOUR

It's happend to me a few times too. If I back it out of the garage and switch it off - It will sometime cough out a little cloud of smoke. I now let the car run at least until the idol kicks down and never see it.

Spec_Davis

it happens to me as well so just let it warm up and it will disappear.

RLE

Quite normal. Cold cats.

Distalero

Or, it's something more sinister, possibly worn valve guides. Kind of a new car for that, though.

It doesn't happen with my C300, and I have a 14 months on it, but it did happen exactly as you describe on a past car, although that had a roots type blower on it, which eventually burned an exhaust valve.

Thing to look for is blowing white smoke. (you didn't describe the color; white is most likely oil, dark grey or black is fuel). When you either get on it, or downshift hard (assuming a manual trans, which I think you said you have), and you see whiteish/blueish smoke: oil. If you see it when doing this, then..........sinister.

By the way, how anyone can diagnose it without knowing the color is beyond me. Another type of ESP?

C300Sport

The smoke was a whitish/grey. I have never noticed it while driving and only very briefly on startups where I have had the very short run times prior to starting up. I made a point to start up and run to the store one time, dry cleaners next time, etc, etc over the last couple days, and voila, no smoke.

Distalero

Well, most likely just the typical condensation (water vapor) in the exhaust system burning off, then, or so I would guess.

Just watch to see if it gets worse, as in it takes longer and longer to go away. If this happens then that would be the classic sign for something not so good.

Maybe one of the 204 engine gurus will chime in here. I've never taken one of these motors apart, and never will because those days are over for me, but there is always somebody out there who's familiar with the telltale signs of bad fuel distribution or an oil leak in this specific motor.