I have an 89 chevy k5 has a 350 5.7 gas engine, it's 4wd. Every time I start my engine after the engine is cold I have a blue/white smoke cloud come out of the exhaust. After I start it up it goes away so it doesn't smoke constantly. I checked the exhaust and it has black sut on the inside of. The idle on it isn't too bad. I've been told it could be a bad valve stem seal or a bad head gasket. I did notice that when I changed the plugs #2 spark plug had smoke coming out of it. I didn't see any coolant on the tips either. I'm leaning toward #2 has a bad valve stem seal hopefully not a head gasket, any help would be appreciated thanks

 

I vote for a bad valve stem seal. If the head gasket was blown and coolant was leaking into the cylinder you would look like a steam machine going down the road. What your seeing is very typical of a valve stem seal leaking by. Oil seeps in while the engine is off and when you start it up it burns all oil off.

 

Ok so if it was a head gasket it wud smoke while I was driving and not just on a cold start up? I've noticed my exhaust fumes are strong too, I don't know if that's why or if its just an old truck problem