[deadtrend1]

If the temperature of your water is normal then its not the t-stat.

I would say, make sure you can hear the flappers moving when you slide the controls. The hot-cold slide moves a cable driven flap. If you pull off the lower dash panel on the passenger side, you can see it. Mine popped off once.

Check to make sure that control valve, (mushroom thingy on passenger side of motor above valve cover) has the vacuum line connected and thats working. Its easy to by pass it with running a line straight from the heater core connector on the firewall, to the water pump (with a barb fitting) or the radiator. Other one goes from the core to your manifold.

I would check those first before I say its clogged.