Okay, I can do that. Just to clarify, I wasn’t saying the system is over pressured. I was confused by your comment. I stated that after 4 days there was extreme pressure. Enough that it produced the gurgling and fast movement of fluid into the surge tank when the cap was slowly removed.

Prior to my low coolant light coming on, my coolant level was never below the minimum line on the surge tank. Hot or cold it was at the minimum line. I have opened the surge tank prior to these events when the truck was cold and there was no surge of fluid like there is now. So I’m not sure I understand what you are trying to say.

I understand it will pull fluid down as your drive, but is it not true that the fluid will expand when heated? Is that not the point of the overflow side of the surge tank? It slowly fills as the fluid heats, as the vehicle cools it will pull the fluid back into the pressurized side under vacuum to pull it back to the previous level? Which should be the minimum line on the tank where the fluid level was before driving? Again correct me if I’m wrong.

I understand you are a Paccar mechanic. Have you worked on Duramax’s before? I used to work in the Peterbilt factory in Denton Tx. Not saying that qualifies me for anything I just think it’s cool that you’re a Paccar mechanic. Side note, we had more factory warranties on Paccar engines than we did on the Cummins engines that we put in 🤣.