The valve in the picture (car as noted) was apparently on the return line in my car. I began to think about that when I developed a leak and had to do an emergency hose replacement. The return line is 5/8 inside dia, output is 1/2 inside dia. The fitting on the valve on the left is 1/2". 5/8" hose was connected to it and routed to the pump (bottom connector). I figure that's where the leak was. Seems to make more sense that the output 1/2" hose would be connected to the valve. But then that means running 5/8" hose to the heat connection. Very confusing. Maybe the problem is the valve got replaced with the wrong replacement at some point in the history of the car. Anyone willing to comment?

Thanks, Gene[http://www.east13.org/valve/im/water_valve_00.jpg]
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The heater valve belongs in the supply line coming from the cylinder head, not in the return line going to the water pump. If there is a 1/2" hose it should go from cylinder head to heater (with valve inline); the return hose to the water pump should be 5/8". I am fairly sure both hoses on your F-body should be 5/8", but could be wrong. If your heater valve is faulty ( they get to where they don't close off the flow) I have a new one on the shelf; send me a PM if you'd like it.

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Too many people who were born on third base actually believe they've hit a triple.

Reed, thanks for getting the picture up there. I'm having a little trouble using the site. I thought I was attaching my picture to the post but I guess not.

Thanks for your post.

Both of the hoses in my '77 run between the water pump and the heater connection on the firewall. Neither connects to the cylinder head. Am I missing something?

Regarding the new valve you are offering, is it the same as the one in my picture? [http://www.east13.org/valve/im/water_valve_00.jpg] I think the valve I removed from the return hose is working correctly. It is totally air tight at least. I'll be putting it back on when I have a chance and I guess I'll see then if it was the source of the leak.

The 5/8" hose on the 1/2" nipple is kind of a common sense choice as to the leak. Considering the mismatch of hose diameter and nipple diameter I wouldn't be surpised if the valve is the wrong one for my car.

Look more carefully. There are two small hose connections on the water pump. One connects via a short (3") hose to the underside of the cylinder head. The other connects to the heater return hose. The heater supply hose connects to the cylinder head, not to the water pump.
No, it's the updated plastic variety -- does not corrode like the metal type.
Yes.

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Too many people who were born on third base actually believe they've hit a triple.

Dan,

I got to check out the hoses on my car on Saturday. The car is garaged about 75 miles from where I live. I see exactly what you mean about the output hose coming from the cylinder head. So I learned something. Thanks.

I also tried putting the valve back, on the chance it wasn't the source of the leak. No good. Does leak big time. I tried a NAPA location to see what they might have in stock. Nothing to match my metal valve with bracket for hanging on the fender brace. The NAPA guy brought up some pictures of valves that he said could be substituted for my unit, including some plastic units. I wonder if I saw the one you are offering. NAPA part no. 6601359. It fits 5/8 hose on both sides.

Can you email me a picture of the one you are offering?

A plastic valve is lighter than the metal one I'm replacing. I wonder if I need to worry about securing it anywhere.

6601359 is NAPA's number for the valve I have. Because it is not as heavy as the metal valve, it doesn't need to be mounted or affixed -- it's happy to sit inline with the heater hose.

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Too many people who were born on third base actually believe they've hit a triple.

I've been through my 1977 shop manual with a magnifying class and there is no doubt at least two diagrams represent the water control valve on the 1/2" output hose. There seems to be no mention in the text about this. The problem with the NAPA item, which is available from a lot of sources, is that the connectors are for 5/8", so no fitting the 1/2" hose on that valve. That leaves the return line for mounting the valve. Is that my fate? As I've written the leaky metal valve was on the 5/8" return line. Put there by a mechanic who never bothered to replace an original valve with OEM. I have no idea how the return-line mount has been effecting a/c output. A/C has never been that great since conversion to the new coolant. Presumably water flow stops and the core is not getting fresh hot water. Maybe water in the core cools down after time. Maybe not. And what about back pressure on the core? I don't think that is desireable. Now I think I understand the leaky valve being non-OEM equivalent -- with mixed 1/2" and 5/8" connectors. Want to comment, Dan? Thanks for your input.