Hi! I'm new on the forum, and I'm very anxious 'bout my 3...

I changed my oil yesterday in a penzoil fast service thing...

today, my check engine lighted on and suddently my temperature sensor got to the max. I stop by the side of the road, closed my engine and waited, it went surprisingly fast down.....as soon as i started back the engine, it would go to the max in a minute or so.

In the same senquence of event, my A/C stopped working...as the heater too

is it a thermostat problem? a sensor problem? I'm pretty sure the engine is ok as i didn't heard the egine coolant boil, heard any "tick" in the engine, everthing seemed fine, except any temp related thing....