No heat

My Sidekick isn't heating up very well. The t-stat & cap are new, I let it idle for 1/2-hour tonight w/the cap off to get any air out, then took it for a drive - the gauge barely moves off the "C" mark & I barely get any heat out the vents. Driving speed/idle/etc. make no diference.

I did notice the fan is always turning whenever the engine is on. I checked & I can spin the fan by hand, but not very freely. It's been years since I've owned anything with a mechanical fan, does it sound like the fan clutch may be bad? I'm running out of ideas for what could be causing this. The truck runs/drives fine otherwise.

double check the T-stat in a pan of water on the stove. Put a thermometer in the water to verify when it opens. Look at the T-stat to make shure it is not stuck open. Do the hoses stay cool to the touch? If not you may have a bad guage/ sending unit.

Sounds as if your fan is normal. As porkboy said, test the thermostat. There are some really crappy stats available.