hi, 1993 f350 7.3 NA...blue smoke on start and idle...not much when loaded ....truck has 217,000 kilometers runs great any suggestions.tks

 

sounds like your burning oil, this could be a number of things how much oil are you losing.

 

Depending on the shade of blue, it could be air in fuel or even anti-freeze. Are you loosing water?

 

It sounds like anti freeze or oil you could have bad piston rings. Since that is very high in MILES the piston rings could be getting worn. If it just when you start the truck that it puffs blue smoke its probably ok the piston just needs to warm up. But check your oil and anti freeze.