I've had this happen twice now - never had a cooling issue even under extreme conditions except when I had a bad fan clutch. That's been replaced by OEM as was the thermostat a couple of years ago. These two instances are literally the only times I've seen the gauge past dead center in 50k miles.

I was going slowly up a rather steep hill then had to stop for a few minutes due to construction. When cars started moving again my van would not turn over and I noticed the temp gauge was close to being in the red. It had been dead center while the engine was running. No steam coming out of radiator or anything like that, but the engine was locked up and would not restart until after I let it cool down for an hour.

It runs fine now but an occasionally seized engine and not knowing when my van is running hot has me troubled. What should I look at?