09 prostar cm871 blue smoke from intake tube

[Sjplcjd1]

I realise a few people might hammer me for this post. I have watched so many Rawze videos my wife might be getting jealous hahah. Went through the forums. Im just needing a starting point.

2009 prostar cm871 615k. Here's the run down this truck had another driver in it about 12 weeks. Prior to maybe 1 gallon between 12to15k oil changes. About 6mpg. Upon returning it is at 4.5 mpg and 3 to 4 gallons between changes. Along with a laundry list of other ticks from just being beat down.

I drove the truck twice Dallas to Austin and back to verify it and see how it ran. 1k miles lost about 1/3 gallon and at 60k loaded with a van and empty back I stayed at 5.1mpg. On the pump not the dash. No smoke at idle but the trailer was covered after the 2 trips. In fairness this is a mid roof without the cap and I pulled a van.

I used a combustion block tester(fluid and bulb pulling air from the overflow) and it tested good. I did it thrice just in case.

So I see no smoke at idle, pull the air filter to check it and listen to the truck idle a little better. And out trickles blue smoke. Not a cloud but a constant and consistent stream. Personally, Ive never it before. 615k and it its the original turbo. No obvious failure oil leaks in piping, seal, power loss ect...

My first thoughts oh turd the dang valves are leaking. But that's a long way to leak back. And why wouldn't that smoke be getting sucked back in to the motor. So in theory I believe it is when im rolling hence the trailer getting covered. I don't think valves but maybe turbo. However im not a great mechanic. And this is theoretical. Has anyone seen or heard of this. Or have other theories. Im trying to figure out where the heck I should start.

Truck smooths out when the magic plug is pulled. Egr tune coming and due. But, I would really like to get to the bottom of the oil consumption first. Truck lived a pretty good life prior to the last 40k