White Smoke.

[yimmy149]

I think the color varies with the oil. My Shell Helix seems to be quite white, but the smell is unmistakably oil.

So far I've only had one really large cloud per about 50 starts, I had to walk out of the garage and wait for it to dissipate. That happened after moving the cold car from a flat surface to an incline without letting it warm up, and then back to the flat surface... an hour later I started it and got a huge cloud.