Short recap for those who don't remember....
2004 Excursion, 6.0, did ARP studs (one at a time method), EGR
delete, full reverse flush on cooling system, ran the restore, flush, flush, flush, ELC coolant.
I was getting some light puking and figured head gaskets. Put in a pressure gauge and It would SLOWLY build to 16psi and then vent. Step on the throttle and the pressure would not jump at all. In fact, sometimes it would DROP! System wasn't over filled either. Had no heat unless it was at high idle or more. Then, out of nowhere, all of the symptoms stopped. No more puke, still a little high for my tastes on the pressure (about 10), got heat even at idle. My thought was maybe water pump.
Fast forward to today when I hooked up to my trailer. Suddenly I'm smelling coolant big time so I'm thinking it's puking again and must be head gaskets. Pull out the pressure gauge (which I have hooked still) and it's at 16. So, I bleed off pressure, run the gauge to my window and start driving. No change at all. I step on it, full throttle, pulling a 5000lb trailer. Not even a flicker on the gauge. After driving it home I check and I'm at about 4psi. A little more driving and it's up at 10 again.
Since there is no fluctuation at all when I stomp on it, can I rule out head gaskets? Does this sound like a water pump issue? I'm getting flow through the hoses, but I don't know if it's the proper amount...maybe my impeller is shot? I'm at wits end here. I need to be able to pull that trailer. I have to replace my belt so I'm probably going to replace the pump anyway since I'll have a bunch of stuff off anyway....it'll be right in front of me. If that solves the problem then I'll know it was the pump, but if you guys have any other ideas I'm all ears.