You brought up some things that I wasnt aware off.
the reason I didnt make a tread is I dont know where to make it. It's not really a build, it's not tuning either. I don't see a help wanted or general technical section
I'll explain the problem with my engine. Coolant level varies too much. Can go from full (cold) to too low (instrument popping low coolant level) .
-My upper radiator hose does not stay hard or get very hard. Even hot with the engine running I can compress it .
-The engine doesnt overheat, doesnt smoke, starts very easy.
-I have no bubbles coming out into the overflow bottle.
-I only add coolant when it puked, at least if the engine drinks any, it's not enough for me to notice it
The WEIRD WEIRD thing is the coolant could have gone up to normal range from running it. Then after engine has completely cooled down, stay up there for a day or two. Leave the truck alone for 2-3 days and the coolant has gone down to where it was before it was run.
What I have done:
-I have bypassed the heater core, with no difference. I blew into them to make sure there was no restriction. I did notice the heater core is in line with the egr cooler. Maybe the egr is blocked.
OH ! I forgot.
When I disconnected the heater core lines, there was air in one of them.
What I think is happening in short. The truck acts like the difference in coolant level is too big for the system. Air probably gets in the system and makes the level appear higher.
I have absolutely NO drivability issues. Drove 400km with a trailer and it didnt puke a single drop. Seems to have more variance of coolant level on shorter trips .
I'm puzzled. It could be headgaskets so I'd like to rule those out or confirm so I have time to change them while it's summer.
Meanwhile im gonna check:
-coolant lines going into the turbo (disconnect and blow in them to see restriction? )
-Block off plate behind engine
Let me know where to post the tread, I don't want to put it in the wrong place