Last night while driving home, I found I had no heat. It was in the low 50’s and I drove about 45 minutes at 55 – 60 MPH. It was the frist cold night I had driven the car this season. Last spring I had changed the Water Valve in my car and after that I know I had heat as I bleed the cooling system with the heat turned up all the way with hot air blowing out of the vents. Now nothing, not even a breath of warm air after driving for an extended period at 50+ MPH. This morning I drove the car again and let it get up to operating temperature and found that the hoses around the water valve are as follows
The two hoses on the right / passenger side of the water valve are both hot. I think these are the “feed” hoses with hot water from the engine.
The lower left side hose, going to the pump is hot.
The hose from the pump to the heater core is warm.
The hose from the heater core to the valve is cold.
Since the bottom hoses on each side of the valve are warm, I am assuming that the valve is working. I believe that the water pump is just for lower RPM I should have gotten some warmth at higher RPM’s. Correct? Could I hook up 12V to the pump motor and hear the pump run to test it. I should say that I checked for voltage at the pump and valve connectors and did see voltage there. I think I am hoping that this means that my heater core may be plugged and I should flush it out. I am hoping that since it worked in the not to distance past, I might be able to clear it with out to many issues. Is it as “easy” as removing the two hoses going into the firewall and adding new hoses to extend them out of the engine compartment and hooking up a garden hose to run water through there. Any comments or suggestions would be helpful. Any more troubling shooting steps I should do.
Thanks

 

One other thing I noticed, when doing the electrical test, the pump voltage was 12+V but the valve voltage was only 6.75V. Could this be because it is from a control box and the pump is from battery voltage. Bad control box maybe?

 

Did you try setting the temp. control to max? This has been reported as being a way to get the water moving. Back flushing the heater core might be called for also. They can become plugged with sediment during the summer months.

 

Yes, I had the controls set to as high as they would go, over and over
Thanks