Blue smoke when restarting truck

[89OBSeast]

My 89 C1500 will produce a small/mid size cloud of blue smoke when I restart the truck after letting it sit for 20+minutes after driving it. No smoke of any color on initial start up if its been sitting for a half day/day or so. I know this means its burning oil. What is recommended I check on first and then so on to get to the root of the problem? Truck has about 65k original miles on it and has been well maintained. Thanks in advance for any insight, I'm new to working on the truck/diagnosing problems.

 

[Drunkcanuk]

Seems like a case of valve seals needing replacement. Pretty common issue with these motors. Good luck. I'm sure someone with a LOT more experience will chime in, but from my reading on the issue, likely culprit.