Hey guys, havent posted in a long while. Im at my wits end with this coolant leak. Quick back story. Have owned truck since '06 about 10 years ago I developed a small coolant leak (adding water every few months). Started to get pressure in upper rad hose. All the mechanics said its a HG, so 8 yrs to date I ripped apart motor replaced HG with "C" gasket used ARP studs, replaced injectors and all supporting parts ie: lines, hardware etc. When I had a machine shop do the heads injector cups were all seated properly and they advised not to mess with them. For the past 8 years its been doing the same thing, having to add water every couple of months. Now its getting worse if I drive more than an hour or so "low coolant" shows. I still get a crazy amount of pressure in system after it has cooled down (next a.m.). I have done combustion gas test on the rad reservoir, shows negative. Reservoir is clean as a whistle, no black soot or anything to indicate combustion gases in system. I have tried all the common things, replacing cap with oem cap, pressure test leaks down 1 psi in the 5 min test, but holds that pressure if left longer. Okay so that might not have been a "quick" back story, but either way, Im at a loss of what to do next. Is it possible I need to pull apart and do injector cups? At this point Im 100% certain it isnt the HG. Any thoughts would be appreciated. Thanks for what you guys do!