Radiator was flushed (not clogged).
AC fan works great.

Fan / fan clutch?

Also, just because you flushed your radiator doesnt meant its not clogged and or not working up to capacity. This was the radiator i took out of my rover that had overheating problems. A new one is $80 :dunno:

Attachment 55393

Yep 80.00 is a small price to pay vs a new engine IMHO. I’ve seen radiators look brand new on the outside, but full of white snot on the inside.

Perhaps a better question I should have asked in the beginning is, how hot is too hot for this thing to be running? What's the norm for 100F weather with the AC on? I'm turning the AC off at 224F, after which the temps drop about 15 degrees.

When my ac is on my engine stays cooler than with it off because the fan is always on
I was just off-roading with the local club and it was hot
lots of bugs and my dog with me
I was wheeling for 6 hours with the ac on
my temps were 197-206
you have other things going on
air in system
I would seal around your rad make sure all the air is passing into the rad area
I would buy a new water pump
I would put the trusted original fan back in
new coolant and new 180 tstat

So the going theory is a head gasket issue. The problem is so slight that we needed to do the test twice because it barely failed. In fact, once it heats up there’s no issue but when it’s cold there is. Two questions :

1. Does this explain the symptoms I’m having?
2. Does anybody know of a radiator with a thicker than 40 mm core?

The car is perfectly drivable now that the temperatures outside are starting to cool off but I will probably do the head gaskets over a long weekend in the near future. At the same time I’d like to upgrade the radiator and fan hence question #2.