C15 Cat Burning 2 gallons of oil every 700 miles

Its not going into thin air driver......how new is the Cat? Did you look in the primary air tank? Did you look at your fuel ? Is it black? Me thinks someone did a raunchy job on the head and the oil is leaving with the excess hot fuel heading back for the fuel tank.

The bummer here is if I'm right the head has to come back off and since it sat for 2 years....no warranty.

Good luck
JMO

 

I say check the fuel tanks as well, if it was that bad going out compressor you would notice it around where drier blows off. The blueish smoke is a good sign its burning it. If the oil is new I have seen it give a blueish tint to the fuel. As previously posted if oil is black there won't be any doubt.

 

Change the oil and pull a heavy load up Saluda or somewhere to reseat everything and see what happens. Is the water temp up where it should be?

Did you check both hot and cold side of the turbo to make sure all seals are good?

 

I just don't think its bad oil. When they sit the oil doesn't really breakdown, its recommended to change due to condensation inside the engine. Even if it needed changed when parked 2 gallon in 700 miles is quite a bit. You might pull the exhaust manifold to see each port individually although usually you find signs in the turbo. That's way too much consumption for guides, if the oil rings stuck in one hole but compression rings are ok that might slow the blowby down and fool you. I never seen it just a thought. Another thought is some cats have a two sided dipstick one side cold eng off other eng running warmed up, could it be an over fill issue and just getting rid of what it doesn't want. Possibly the wrong stick cause it was lost. But even this would show signs of it spitting it out the tube. If blowby was clogged by dirt dobbers or anything else it would spit oil out the turbo on the pressure side or air to air have you checked that side? Bad seal in turbo would do that as well but usually shows oil on the clean air inlet side. I reread your first post try looking in the Air to Air boot out of turbo for oil and the inlet thats bout only place left it can go. By running through the air to air into the intake it would burn it making a little smoke. Be sure to check that blowby tube is open

 

That's way too cold. Could be the rings not sealing good. Change the thermostats and get the engine good and warm and it may seat back up. Plus you won't get good performance or fuel mileage, not to mention heat for the cab with it running that cold.