Bad sensor or just use to bad readings?

Yesterday I replaced my water pump because it went out but in the process, broke the temp sensor at the thermostat. Got the sensor replaced and the new pump on, filled it up and such, ran it for a bit, cool it down, re check, etc... But the issue I'm having now is the temp gauge shows it lower than before, after the jeep has sat for 45 min warming up. It goes to the notch under the 210 notch. But when driving it 35 ish mph and up it drops down another notch like this

Is this a bad sensor or thermostat? Or am I just use to high temp reading from a dying water pump?

195-210* is the normal operating temperature. If your temps are low, double check the temp display with an IR temp gun, and consider replacing the thermostat which is probably stuck open.

would 220 plus degrees cause a thermostat to do that, reason for asking is i replaced the thermostat 6 months ago, to early for one to fail right.

The replacement sensor I got was off by 30 degrees out of the box. I'd check it against an IR thermometer or mechanical gauge.

If the engine got hot enough to make you replace the pump, it may have ruined the T-Stat, and left it stuck open. The sensor may be off too.

Ecomike said:

If the engine got hot enough to make you replace the pump, it may have ruined the T-Stat, and left it stuck open. The sensor may be off too.

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The pump went out because the belt had been to tight, I had tightened it using a krikit(dumbest thing in the world lol) and later learned of the failures of pumps and such because those things are off. Loosened the belt to save my pump but it was too late lol. But the sensor was replaced after the pump, just trying to figure which one it be before buy or wrenching first. Ill try the temp gun and see If the engine is coinciding with the temp gauge. If its not , coolant temp sensor, if they are both the same, its the thermostat right?

I don't know if this works for all jeeps but it does for my 97'
Didnt have a temp gun to find out if the engine is at the temp gauge says but I came to the conclusion that my thermostat is out because before this my heater produced excellent hot air at the hottest setting, but now it produces only mediocre heat and when I'm driving at 40 and plus mph and the gauge drops another notch, the air coming out the heater gets colder. I stopped and let my engine sit and the gauge went back up and the heat also went back up. So I just put two and two together and realized my thermostat is out. Don't know this little info helps, I guess you would need a good working heater in the first place to know but hopefully it helps

If you have an obd2 jeep, you can hook your scanner up and see what temp the sensor is sending to the pcm, which should be the same as what your dash gauge displays.

Demonoid369 said:

The pump went out because the belt had been to tight, I had tightened it using a krikit(dumbest thing in the world lol) and later learned of the failures of pumps and such because those things are off. Loosened the belt to save my pump but it was too late lol. But the sensor was replaced after the pump, just trying to figure which one it be before buy or wrenching first. Ill try the temp gun and see If the engine is coinciding with the temp gauge. If its not , coolant temp sensor, if they are both the same, its the thermostat right?

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Krikits are completely useless. We tried using one on my Jeep. My solution was to tighten it 1/8 turn until it stopped slipping every time I turned on the headlights and tried to make a turn.