Thanks. I bought (and verified) a new thermostat to install sometime soon. Can I just use (fluoro)silicone to re-seal the housing to the block, or do I need a special gasket (or can I re-use the old one)?
I have the mechanical/electrical setup; even in the summer, I only hear the electric come on in very extreme conditions, but the temperature is always reading lower than what it is now (always well below the little thermometer on the gauge, whereas, at 210°F, the needle is over top of the bulb of the little thermometer). The mechanical fan is working, and its clutch feels about right.
With a new rad, and nice, clean fluid drained from the old one, I'm not too concerned it could be a clog.
I felt the radiator today after letting it idle and getting right up to temperature, and it wasn't very warm (it was a bit, but not much). Not sure if that's normal, but I expected hotter.
1996 Caprice Classic: LT1, B4U, DCM/ruby cloth; stock except for side trim removed
2009 Pontiac G8 GT: maverick silver/onyx cloth; mods: Solo Mach catback + resonators + HFCs, AEM short ram, Livernois ECM/TCM tunes