Need help with heater hoses and control valve

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Jan 20, 2022
Messages
1,123
Reaction score
1,862
Location
Homer Glen, Il
My Car
1971 Mustang Mach 1 351c FMX trans and 9 inch rear end
Hi All,

I am starting the install on the heater hoses and I have a few questions (here is where my lack of Ford experience kicks in). I realized that I do not know the flow pattern between the heater core and the water pump and block ports. Also, I am trying to buy a heater control valve and NPD has one without a bracket and has arrows indicating the flow can go in either direction for this valve. Unfortunately, this valve has been out of stock for the last month and they told me on the phone they do not know when they will get more in stock. CJ Pony (not my first choice for suppliers) has one but there is only one arrow cast in the case of it which seems to indicate the flow can only go one way, and this valve has a mounting bracket. Can someone please tell me which style of valve is correct for my 71 Mach 1 351C with A/C? If it is the style that NPD offers, does anyone know where I can get that style without waiting for NPD to get it back in stock?

Hemi Killer posted a great diagram (see attached) of the routing in a different post I found on heater hose routing which was very helpful in the routing aspect, but the drawing overlaps the two hoses as they run along the intake manifold. I am unable to determine for sure which hose is which from the engine end to the heater core end. It appears to me that the water pump outlet hose is the one that has the control valve in it and it is attached to the inboard port of the heater core and the hose attached to the outboard port of the heater core runs directly to the nipple in the block, is this correct? If it is, am I correct in assuming the flow runs from the water pump through the control valve and on to the heater core and then returns to the block? If this is the correct flow pattern then it appears that the CJ Pony valve's one way flow is backward to the bracket orientation. Where the bracket could be mounted on the intake the flow arrow points the opposite direction. It does look like the valve and bracket could be swapped around to work though. I appreciate any help I can get regarding the flow and the correct valve style and if anyone has used either of these valves themselves. Thank you

Mach 1 468.jpgMach 1 470.jpgheater hose routing.jpg
CJ heater valve.jpgNPD water valve.jpg
 
Last edited:

Latest posts

Back
Top