Heat Contd.

I pulled both of the heater hoses off of the firewall (after I clamped off the hoses). These go straight into the heater core. I shoved a hose in there and flushed it completely, from both directions. Water flowed freely. This meant that I did not have an issue with the valve or the vacuum switch or blockage in the core. I hooked it back up and "bled" the cooling system (to get out any air bubbles). It seems to work much better now, but heat is still somewhat dependent on engine RPM. Possibly I need to replace the thermostat. It may be stuck. We'll see how it runs this week.