Where are all the running hot posts?

YY1 said

Mine normally runs about 170.
...unless the AC is on. Then it can go to 210 or more.
Still trying to figure that out.

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Very same condition in nephews 2002 4.3 ltr Blazer. Bad fan clutch was the main issue. My advise was, While at rockauto for the clutch, get a thermostat, upper rad' hose (looked to be OEM), and a serpentine belt (it was cracked up badly and going to come off to get at this thermostat anyway). Found rubber gasket around thermostat broken up so it was likely OEM too. The problem is cured and some maintenance done.
I didn't overheat while sitting in the shade coaching his labor. I can pretty much predict his radiator to be the next failure (OEM, put together with rubber gaskets also).
for what its worth, our 73 318 Valiant factory a/c had 26 inch radiator with fan clutch and shroud.