Very frustrating day today. I was supposed to go to hunting camp in the cold mountains tomorrow. Not happening with no heat or defrost. Started the day by replacing the heater control valve. Bled, burped, squeezed hoses. No heat. No circulation through the system with the heater control valve unplugged, and I could easily blow through the valve I removed. Not the heater control valve. No water flow, well the darn pump must not be working. Replaced the water pump. This car has the electric fan, so pretty easy. It was most likely the original water pump as the o-ring was pretty flattened and white residue all over the place. Remarkably solid design. Re-filled, burped, squeezed, drove 90 miles, up a super steep hill, down the other side, bled, burped. No heat. Back to the shop with my dander up, I installed a 12V transfer pump in line, sucking from the top heater valve port pushing into the hose normally attached there. I did get a tiny bit of heat in the cabin. Excited, I figured I had cleared an air lock of some sort. Restored the heat valve plumbing, drove 40 miles, sometimes at high RPM. No heat. Removed the heater valve from both lines. Started the car, revved, a tiny trickle of coolant is coming out of the line to the engine. No coolant pressure available to push through a completely open control valve? What the heck? Anyone seen this? Why is there no coolant flooding out the line from the back of the engine pressurized by the water pump?