Need Heater Help

[lts70]

I have installed a Sure-fit system from Vintage Air in my 1970 Chevy C-10. I have everything finished and I am very impressed with the system and how cool the A/C gets. My only problem is that the heat is not working for me. I installed the custom coil unit so that I could shave my fire wall and run a 4-way bulkhead. I have the heater valve in the cab in-between the unit and the bulkhead at the firewall, on the line coming from the intake manifold. I took the hose off last night at the valve to see if for some reason the valve was not letting coolant through. When I had the hose off it drained enough coolant to fill a 44 oz. soda pop cup. I put it back together and ran my heater all the way to work this morning (20 miles, 30 minutes) it blew cold air the entire time. I put my hand on the valve itself and it was hot so I know fluid is getting past the valve and that it is hot enough. Is there something I am missing? Can my heater core not be letting the coolant through and no circulation is my problem? The only thing I can figure is that some how the heater core is blocked, I thought it might be some sort of vapor lock from air in the core maybe but after taking off the hose and having the coolant come out I ruled that one out. Any advice on how to solve this would be greatly appreciated as winter is coming and this is my daily driver right now.

[cdowns]

where are your supply and returns hooked up on the motor?

[Tynee]

I'm not familiar with the system, but as you are describing the problem, I suspect maybe you have a diverter somewhere that is not letting air flow across the core, just a thought.

If you suspect that the core is not letting water through, you can easily verify by checking the temp of the return line, the same way you did the supply from the intake manifold (unless the return line isn't accessible in this system).

Oh, and since it's sometimes the simple stuff that you don't think to check, how's you coolant level in the radiator/reservoir?

[lts70]

The supply comes from the intake manifold right by the radiator hose inlet. And the return goes right into the water pump. I double checked my control cables and they are in the right configuration and I have the control levers set to where the vintage air instructions give for heat mode. My coolant level is all the way at full. The only thing I can think to do is undo my return line from the water pump and get the truck up to temperature and see is the coolant flows through the core, maybe there is an air bubble in the core and by undoing the return line it will relieve the back pressure and push the air out. Is that even a possible problem, air lock in my heater core? I can not think of anything else.

[lts70]

Well I removed both heater hose lines and ran water through the core. So it seems that it is not the heater core. I have noticed that the truck is running a bit hot I don't know how much as my temp gauge kind of works when it wants to, I cant find where it is grounding out but a lot of times when I turn the truck on in the morning it is pegged out at hot. I had my hand on the upper radiator hose to see when the thermostat opened. It did and the hose got hot but the hose did not build any pressure it seems. The water pump was squeaking a little but other than that seems fine. Could the water pump not be pushing enough pressure to fill the heater core and more importantly to cool the truck properly?

[Tynee]

Originally Posted by lts70

Could the water pump not be pushing enough pressure to fill the heater core and more importantly to cool the truck properly?

Yeah, that definitely could be a problem. If you're certain that the squeak you hear is coming from the water pump, I' replace it anyway. Sure sign the bearings are past their prime

[lts70]

I installed a new water pump, squeak is gone.....but still no heat coming out of my vents. Could it be a thermostat that is only partial opening? Any Ideas or suggestions would be great.

[LockDoc]

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It sounds to me like you have an internal air control door inside the heater that is not opening so you are getting outside fresh air coming in instead of air through the heater core... Just a guess.

LockDoc

[Tynee]

Originally Posted by LockDoc

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It sounds to me like you have an internal air control door inside the heater that is not opening so you are getting outside fresh air coming in instead of air through the heater core... Just a guess.

LockDoc

Second that. It goes back to my original suspicion. Do all of the control levers move with equal ease? The one labeled "AC/Heat cable middle lever" on page 11 of this link:
http://www.vintageair.com/DownloadsS...ols)%20Ine.pdf
is the one that I suspect is either detached from the lever, detached from the little stud at the flapper, or has broken the flapper loose, and is really only rotating the "axle" of the flapper door. If you can put one hand on that little stud while you move the lever back and forth with the other hand, you should be able to tell where the problem is. good luck!!