I was wondering is there a way to test coolant temp? I switched my instrument cluster from lights to gauges and oil isnt working at all, still need to find the right sensor. Have tried 3 different ones. Anyways. The coolant sensor is.....kinda working. Im not sure though, hence why im asking. The gauge does move but stops at around 150. I thought the sensor must be bad. But im able to go one a 30 min drive and place my hand on the radiator cap with no problem. Its not even hot, just pretty warm. Kinda leading me to think maybe my engine is just running super cool somehow. Is there anyway to test coolant temp in a manner that doesnt require removing the sensor?

 

An IR temp gun will tell you a lot, recently used one to diagnose a bad sender

You dont say what year, but if '96 or later, use a Bluetooth OBD2 scanner, shows live data, including coolant temp

 

You have a thermostat issue if you can hold your hand on any part of the cooling system.