Okay, seems like a thermostat on its way out. I've never had one that didn't just flat out dail so I want some opinions.
Wife started vehicle, vents blowing cold air. Temp gauge went up to 3/4. Gauge finally went down to just under half and then vents started blowing hot air, while driving temp gauge will go up with no hot air, then gauge wil go below half and blow hot air. I was going to change thermostat. I checked water pump and there is no play in the pulley and there are no coolant leaks anywhere.
Thoughts?