Have you ever wondered why your truck acts up right after someone else drives it? No issues for years and right after my GF drives the truck, the temp gauge stays just above C after driving for an hour. I know it's not her fault, just saying funny how that works. This was yesterday.

Anyway, while driving to work this morning it went up to normal temp (halfway) and next time I checked, it had swung to the left again. I then watched it rise from C to normal temp in just a matter of seconds. So this can't be the thermostat, which is a Stant that I put in about 5 years ago... no way it could change temps that fast. I'm thinking the coolant sensor is on the fritz. Have you guys used aftermarket sensors?

Looks to be real easy on a 4.7L

 

Screw it...just picked up the Mopar sensor on Amazon for about 45 bucks. It's double the aftermarket prices but I won't have to think about it again, probably for the life of this truck.