Cat C15 blue smoke and blowby

I have an 05 NXS twin turbo c15 that has about 935k kms. Truck had blowby when I bought it, and slowly it’s been omitting more and more blue smoke. I can really notice it pouring out when under load in soft ground, goes through a bit of oil but not an insane amount.
Talked to a mechanic that is going to do the work for me and he figured it was an over fueling injector, or injector o rings. Is this a safe assessment or could it be piston rings.

 

Hey there, blowby is coming out of the breather tube (slight grey haze but pretty constant)

blue smoke is coming from the exhaust aswell as underneath the truck, but there’s a few exhaust leaks so I figured it was from there. The blue smoke is not constant, but is getting much more prevalent and thicker.

 

I’ll have the mechanic look into that once he opens the head up for sure, thanks! Yeah this one doesn’t even have a million kilometres yet and I’ve heard these should last 1 million miles, injectors would be a good replacement

 

Yeah the blowby is pretty much a constant, at startup and operating temp.
The main concern now is the blue smoke from exhaust. It doesn’t all the time but under load it gets pretty heavy between O rings and injectors. It seems blue smoke indicates an oil issue. I’ll definitely look into that 16:1 if I rebuild, thanks for the reply!