Last month I was waiting for my kids to get out of school (a/c on and hot outside) and noticed the engine temp gauge just a tad above where it allways stays. When my kids got in and we started out the drive the temp started moving toward the Hot mark. It got pretty close to the mark before I panicked and cut off the a/c and turned on the heater full hot and full fan.
(we we moving 20MPH or so) When I did this it stayed where it was for a few seconds then fell back to normal shortly therafter (quickly). The coolant level was and still is full. I do not drive this car much and am wondering if this is a normal quirk with the car?
this is not a normal quirk, make sure your fan is working, and your water pump still works
Your engine cooling fan is turned on by the engine computer before the engine gets too hot. Listen for the engine cooling fan when the engine gets warm (about half way on the temperature gage). If you don’t hear it, tell your mechanic. Also, a sticking engine thermostat could have caused the sudden temperature rise. If the engine cooling fan comes on, and the temperature keeps climbing, suspect the thermostat.
One more suspect: debris. There could be debris (rust scale, piece of something) in the coolant. It could have, momentarily blocked a coolant passage. It could help to have the coolant drained, the system flushed, and new coolant put in. (Regular maintenance-wise, it’s time for coolant change, anyway).