340 Overheat / Radiator Geyser

This is the last of the troubleshooting that I’m gonna do on this thing before taking stuff apart. Not sure if I mentioned yesterday’s pressure test. As I said the gauge on the tool quit, but I manipulated it to get it to work. I can’t speak to the accuracy, but I cranked it up to 15 psi. After 30-minutes it dropped 2psi, but there was a visible small drip from a heater hose connection.

Today I ran the car at idle for 20 minutes then started taking temps. Temp gauge was at ¾ by this time and still climbing slowly. Heat is always hot. Gauge never goes up, then backs down as-if thermo was opening, so after all this maybe it’s just the thermostat.

Hose temps were taken at the clamps as someone suggested. These are original wire type clamps.

Upper hose at engine-212, at rad-202
Lower hose at engine-156, at rad-149
Upper tank at hose-206, center-206, R side-205
Thermo housing-210
Water pump housing-172

The 37 radiator “passages” ranged from 108 to 188 (suspicious?)

This time I left the radiator cap on. At 18 minutes I started to get some discharge from the cap overflow but not much. Upper hose did not feel firm until late into the experiment.

Phase II. I let the car cool for 2 hours.

Ran it for another 20 minutes, this time with the cap off. Did not take any temp readings because the thermometer quit altogether (overheated, ironically). Same results. Temp rose to ¾+. Coolant again dumped from the radiator after shutting down.

Remember guys, I have very limited resources at this time in my life. If I had even just a driveway to work in, I’d just pull everything and maybe send the radiator out, then go from there. I also can do grunt and detail work like nobody’s business, but I SUCK at diagnosing/tuning, stuff like that, that’s why I’m trying to get maybe some idea of how you think I should proceed with this thing. Sunday (Sunday…SUNDAY !!) I’m gonna try doing a good flush and replacing the thermostat, as well as testing the old one. Thanks again.