87 Ram 50 4x4 "junkyard" rescue,

[MrPaco]

One word of caution on running cool. It's a 30 year old gauge, with a who knows how old temp sender, possibly corroded connections.

Interesting observation, makes sense.
Are there any temperature test that can be performed to somewhat get an accurate reading without replacing the sender/gauge? I don't mean continuous accurate readings, like if you had a new sender/gauge, but a specific test you can do. Like running the engine hot and measuring the temp of the coolant, or something like that, and then comparing that to the readings from the gauge.

[geezer101]

Interesting observation, makes sense.
Are there any temperature test that can be performed to somewhat get an accurate reading without replacing the sender/gauge? I don't mean continuous accurate readings, like if you had a new sender/gauge, but a specific test you can do. Like running the engine hot and measuring the temp of the coolant, or something like that, and then comparing that to the readings from the gauge.

Neanderthal tech - put a thermometer on the top tank when it's hot (peak normal operating temp) and see what the surface temperature is like. Not super accurate but it'll put you in the ball park. Even an infra red reader will be better than a guesstimation.

[MrPaco]

Sounds like something I can handle.
And what are some of the temp ranges to look out for? What temp is running too cold, proper or too hot?