Jeep LJ 4.0. So the water pump went out and now the temperature gauge is all over the place. Was consistent at 200-210 till the water pump was changed. Around town it's running around 160-165 now no matter how much driving if its just stop and go and will get around 190-200 after 20-30 minutes of highway driving.
It has the K&N filter which I know some say to go with a low temp thermostat of 160 so I was thinking someone may have changed it out before but then why would it have been consistent at the 200-210 range before. Unless the water pump wasn't working correctly before and now the new water pump with the possibility of a previously changed thermostat to 160 and now it's maintaining that temperature more consistently.
Other possible things I've considered we're the coolant temperature sensor, the fan clutch, or possibly a bad thermostat.
Any idea what I should start with???? Makes no sense to me. To many what if's.........