ISX engine 800k miles burning oil

[SBTA]

Hey one of my isx engine burns around (1-1,5)gallons of oil after 8000 miles from oil change on light loads...and can up to 3 gallons with heavy loads in mounts...have been to a couple mechanics to find out oats going on...i have done an oil analyze a the Speedco they find light amount of coolant in oil, cooler charge have beed replaced, they have done a pressure test in coolant system they say its normal...i have few leeks from deep stick, from the compressor tail but i don't believe can dump from that point in so big amounts...so i explain how is it with my words...for any ideas beside for an overhaul, my mechanic say if it burns more than 2 gallons that internal parts...i got this truck with 540k and it they have done some repairs inside of engine... (previously owners )
THX

[Waterloo]

Fix the leaks and go from there... The 1 - 1.5 gallons sounds normal for an older high mileage ISX between oil changes. The 3 gallons if pushed hard, I could see it. They do not run forever. And then throw in your oil leaks... I am guessing one at the compressor? You can lose a bit of oil between oil changes there if left to leak. Have you changed out the crankcase breather filter? You said you had coolant in the oil? I wonder what your pressures are like internally? That is just off of the top of my head from what you wrote, smarter individuals will hopefully chime in.

[SBTA]

Thx for replaying about 3 months ago my coolant tank start to leak so i checked the pressure in the system to be honest it was some pressure, but mechanics saying its normal, if i'm not wrong from (10 si 15 psi) but about crank case filter i need to replace to becouse its more than enough miles already on that filter... from what i heard usually if its bad worn inside is could have a strong dirty blow by and crank case filter its clogging out quick...but small amount of coolant i can be from the head gasket?
Yeah i'm agree they a not forever but any way its good to know for what you paying when you looking for a service.

[Waterloo]

Well... My head blew at roughy your mileage... I have the CM-871, 2008 ProStar... The head was toast, but had the entire in frame done along with a bunch of other stuff... If it is a bad head, which more than likely it is, especially if you still have the mandate on, at least buy a NEW head, do not go reman or rebuilt. Spend the few extra hundred dollars and do it right. The rest of the motor is up to you. I probably could have gotten by with just a head and a lower end bearing swap... But, knowing enough about this stuff, i went the full monty and bit the bullet. It was an easy decision to make. They don't build these things like they used to.