Must be the fan. As a matter of fact, when I see my temp gauge start to creep up (not into the red, just a letter or two), I actually turn *on* my a/c, and the fan kicks right in and the needle heads back toward the "O*R" are. Go figure.
Old car: '98 SVT T-Red
K&N air filter; Ford Focus RS shift knob. Off to be auctioned off somewhere.
New car: 2003 Honda Accord DX Sedan, 5-speed.