[mdwilf]

Lots of good input here. I would look down in the radiator, see if the ends of the cores are clean or crudy. If crudy, fill the rad with vinegar & let it set a few days.

Before I did too much work, I'd verify the gauge, sender & wire are good & that the gauge & sender are compatible. Shroud will make a huge difference, but I've run several without it.

When it starts showing hot, turn on your heat & see if it feels unusually hot. If you get caught out in an overheating vehicle, turn the heat on full blast, this may save your motor. You'd be surprised at how much you can cool a motor down this way.

Be wary of the cheap aftermarket temp gauges, I've had several that were inaccurate.