Sometimes, the bear gets you. My tester showed my system was still losing pressure.
Sigh. Because I want to get out of town and back up north, I had RTVed up the stock thermostat gasket and reused it. Sadly, the gasket didn't hold a seal. This time I took the time to make a new gasket out of gasket material I keep around.
But no good deed goes unrewarded and when I was loosening the rearward bolt of the T-stat housing, the bolt stuck in my swivel socket as I pulled it up, and as I thought, "Noooooooooo!!!" and the radio played Beck's, "I'm a loser, Baby, so why don't you kill me!", the bolt did a Peter Pan and vanished behind the water pump housing.
The first step of bolt recovery was to get a lot more space under the hood. I decided the best way to do with was to use a pair of tie-downs and hook the ends to the cab mirror mounts and hook the tie-downs together under the hood. When I pulled the pin to the gas rams, I then lifted the hood up and tightened the tie-downs to hold the hood straight up.
I then proceeded to tear apart the turbo induction plumbing to gain access to the water pump.
I don't know about you, but my mind tends to wander, and so while taking things apart trying to find the missing bolt, it occurred to me that all this sensor is doing is measuring pressure differential and that a test tube with the proper restriction could do the same thing.
And this sensor? An O2 sensor or an exhaust temp sensor? A test tube with fittings? I should consult the service manual to determine what these sensors are doing.
Anti-freeze leak number 2 turned out to be a dealer installed leak from the optional heater core.
The problem with the optional heater core is access. It is a 30mm hex with no room for a wrench swing or a socket and so the tech likely tightened the heater core as best as he could. My solution, 30mm is close enough to 1-1/8" and so I used my 1-1/8" wrench and an extra-long 1/2" wrench to snug this rascal up. I snugged the heater core up, but the pipe tape looks like I may need to pull the core out, re-pipetape it, and do a fresh install.
I suspect I may still have yet another anti-freeze leak, but I had to quit to go in and watch the Walking Dead. I'll hit the system again with my pressure tester on Monday, weather permitting.