Temperature gauge reads center, then works towards hot, about three-fourths the way, then comes back down to center?

JDSTARNER

MEMBER
2016 FORD F-150
3.5L
6 CYL
4WD
AUTOMATIC
150,000 MILES

So, a new water pump installed in October of 2022, this past week a new thermostat and coolant temperature sensor installed as well as a new throttle body.
Now what's going on is, when driving to work in the morning, the temperature gauge reads in the center, then in the afternoon it goes to center, then works towards hot, about 3/4's the way, then comes back down to center. Goes back and forth. When I come to a stop, it will sit the center and seems normal. After stopping at the store for 15 minutes, upon starting the truck up, the temperature gauge went to hot, after 30 seconds it came back to normal.
Could this be an issue with the new sensor? The built in resistor is not working at 100%? Or something else?

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

When they replaced the engine coolant sensor, did they use an OEM unit? Or it could have been over tightened which can damage the sensor or there is a bad connection at the sensor. But I would check the coolant level. Here is the location of the sensor so you can check it out. Check out the images (below). Please let us know how it goes.

Images (Click to make bigger)