Good morning. My 99 K12 has just over 220,000 miles and I've not had to touch the engine. A clutch, exhaust system and a rear bearing, but nothing on the engine. I recently noticed that when I start it in the a.m. it blows a puff of blue smoke, then it clears up and runs great. Is there anyone else out there with this many miles that has the same problem? Thanks in advance.