Smoking at startup

[8950LX]

Chevy was notorious for using o-ring type valve seals on most of its engines. On a higher mileage motor they almost always leak down when the vehicle has sat for awhile such as overnight. I would suspect that when you start your Astro your smoking problems are a combination of leaky valve stem seals and condensation in the exhaust system. Hence the whiteish smoke only at the initial startup. My wifes 92 Astro van has been doing this since about 80k. It now has 177k on the original motor and the heads have never been off and has never lost any coolant. My brothers 95 Astro has 244k on it, same smoking as you described. Pressure check your cooling system to be sure. Just my 2-cents, hope it helps. Good luck.

Bill