With a little prodding from Art, I began to try and troubleshoot why the thermostat (when installed) is not getting hot water to it. I began to look at where it should be coming from and try to determine if there were any blockages or impediments.

Reference Diagram:

IMG_0571.jpg

I started with the heater hoses because I thought that those would move the most water. I removed the hoses at points A and B in my diagram. This is the return from the heater core to the thermostat housing. I was able to use my air compressor to blow low pressure air (20psi) through the line from the back of the block (point A) to the T-Stat housing (point B), indicting that line was open. Next I unhooked the outlet of the water pump that feeds to the heater core (Point E). Then I started the motor up and made sure that the water pump was pushing water out of the feed to the heater core . It did indeed push a lot of water through that pipe (about 0.5 gpm). then I hooked my hose up on low into the feed to the heater core (point E) and let it push all the way through the core and back out the return line (Point A). This indicates that I have a free path from the water pump, through the heater core, and back to the thermostat. My only thought there is that perhaps with the T-stat installed there is not enough head on the water pump to allow it to push water out to the heater core (point E). With no thermostat it was pushing 0.5 gpm, but I'll have to test it again once I reinstall the thermostat.

I also checked the line from the degas tank (point D) to the Thermostat housing (Point C) with low pressure air, and that line is free as well.