suddenly heat guage goes to 1/2 way point after only one three miles

esoxslayer

What should I have mechanic look at? I doubt that the sudden change is the radiator or thermostat, one, because it is sudden, and two, because the needle moves up to the half way point too quickly. So, what probably is the cause?

esoxslayer

Also, heat blows out vents

Mr_Shiftright

Might be the sender or its wiring, or the gauge itself. I agree with you, that's not how a thermostat usually acts.