1990 / 305 smoking big time
 

I have a 1990 K1500 truck with original 42,000 miles on it. The problem seems to be that I noticed that just this winter when I would start it in the morning before work it would have a burning oil smell from the exhaust. This motor has never used oil before and it doesn't seem to as of yet but I had the oil changed at Jiffy Lube, Yes Jiffy Lube, I know bad move but after all it is winter and I didn't really want to get under it myself. When I leave in the morning I leave a trail of blue smoke where I was parked and when I sit at a stop light I leave the person behind me in a oily smelling cloud of blue smoke. For the amount of smoke it seems that I would be out of oil by now but it still registers good. It doesn't smell like gas either It doesn't apper to smoke while going down the road. Any Ideas ?

Possible bad valve guide seals.

It's not very likely, but if the problem arose all of a sudden, your PCV system may be introducing oil into the intake, causing the burn. (Blue smoke is oil smoke.)

It is more likely that you have a valve guide seal problem, a broken oil ring, or a crack in the head or block from the oil jacket to the intake port. Head gaskets could, but not very likely.

It sounds like it smokes all the time. That makes a valve guide seal issue less likely, unless it is really, really bad. If it is only when the motor is cold, and stops after warm up, then the valve guide seals become a more likely culprit.