For a little history, bought a TL8 from a cattle operation in SC via auction 4 months ago. Listing had 3 photos, said the hours were unreadable (screen not working), starts, runs and operates but smokes badly.
I got a good deal IMO, even if she needs a full rebuild.
Sure enough, she runs great for a time. Lots of white smoke (smells of diesel and maybe oil), under operation. Sometimes she overheats and shuts down. Wait a bit and she'll fire back up. I pulled the operator screen off, cleaned it carefully as well as the contacts on the board, plugged it all back together and the screen works great. 2200 hours on the clock. No codes, no demand to run a regeneration.
So, here we are. Spent the weekend pulling the air, oil separator, turbo and dpf off the machine. Cleaned it all. Major oily mess all around.
Oil Separator filter looked original so it got replaced.
Turbo got a good soak, then hot water and the pressure washer washer made it shiny again. It barely spun using my finger to push the inlet around. Exhaust turbo was caked with black tar like crud.
DPF, pulled it apart, soaked it overnight in hot water and dishwasher powder. Hot pressure washer clean. Clean as a whistle.
Put it all back together and it's the same issue. It sounds better overall but still getting some
Also, some pressure in the crankcase ( I hoped it was a breather hose or the filter clogged) when I open the Oil filler cap.
I should have run a compression check while I had the head exposed but I needed it back together and running for a few jobs around the farm.
I'm guessing it's rings.
QUESTIONS: What is the likely culprit? How critical is it to fix it asap VS. doing damage? Approximate cost for the rebuild?
What am I missing?
I'm thankful for the wealth of knowledge on this site. Thanks everyone.

I got a good deal IMO, even if she needs a full rebuild.
Sure enough, she runs great for a time. Lots of white smoke (smells of diesel and maybe oil), under operation. Sometimes she overheats and shuts down. Wait a bit and she'll fire back up. I pulled the operator screen off, cleaned it carefully as well as the contacts on the board, plugged it all back together and the screen works great. 2200 hours on the clock. No codes, no demand to run a regeneration.
So, here we are. Spent the weekend pulling the air, oil separator, turbo and dpf off the machine. Cleaned it all. Major oily mess all around.
Oil Separator filter looked original so it got replaced.
Turbo got a good soak, then hot water and the pressure washer washer made it shiny again. It barely spun using my finger to push the inlet around. Exhaust turbo was caked with black tar like crud.
DPF, pulled it apart, soaked it overnight in hot water and dishwasher powder. Hot pressure washer clean. Clean as a whistle.
Put it all back together and it's the same issue. It sounds better overall but still getting some
Also, some pressure in the crankcase ( I hoped it was a breather hose or the filter clogged) when I open the Oil filler cap.
I should have run a compression check while I had the head exposed but I needed it back together and running for a few jobs around the farm.
I'm guessing it's rings.
QUESTIONS: What is the likely culprit? How critical is it to fix it asap VS. doing damage? Approximate cost for the rebuild?
What am I missing?
I'm thankful for the wealth of knowledge on this site. Thanks everyone.

