I've got about 150K now on my truck, and I've noticed that it puts out some blue smoke when I start it up cold for the first few minutes. I usually only let it idle for about 3-5 minutes before I take off, so I don't know how long the smoke lasts, but once the truck is warm it doesn't happen.

I bought the truck with 130K miles, and it did it then too, so I wouldn't say it's getting worse. I don't have any oil consumption that I can tell on the dipstick.

Is this normal or am I looking at engine (possibly valve guide) wear?

 

I fought with this for a year. It's unburnt fuel causing the blue smoke. Look for retarded timing, bad injectors and boost leaks. Replacing the injectors helped my smoke problem the most. According to a couple mechanics I talked to, you're at the mileage where they probably need replacing.

 

normal read this https://www.dieseltruckresource.com/forums/showthread.php?s=&threadid=36948&highlight=blue+sm oke
ramguy

 

Read this and see which category your smoke falls into
http://www.freeautoadvice.com/diesel/smoke.html