Is it time for rebuild?

I would verify that the blowby you see is not actually water vapor. Stick your finger up the bottom of the blowby hose or tube and you'll see for sure.

If not, definitely prepare for an overhaul, but oil consumption is a better gauge than blowby IMO.

An oil sample would help, but without a baseline to compare to, the info wouldn't do you much good now.

 

Op, that’s not blowby, put the truck on a dyno to check the blowby and see what the actual blowby is. It is measured under a full load, not looking at the draft tube for vapor.

Do an OA, it will tell you what’s in the oil … you should have been doing that since you bought the truck.

 

If it’s not using g coolant or oil, I would run it. My former Cat had some blow by when I used the newer oils, so I went to using a different brand, Conoco Phillips GUARDAL was the brand if I remember correctly.

 

Pretty common to see a CAT chuffing out the tube when hot due to open Crankcase. Get worried if it starts dripping or leaving a puddle.

Run it….

 

Sounds pretty normal to me even if the tube is oil soaked.

 

If that mileage is accurate and the engine hasn't been touched yet I'd start putting money away for an overhaul.