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Temperature Control Valve In Our Heater Hose?
Has anybody seen this before? So old it looks correct but no markings on the part that is inline with the heater hose, but part is a Ford part as far as the "switch". The upper connection has an "E" on it so thinking EGR?"?.
Looked at vac diagrams and it may be for the ERG on a 73? Thinking it is was be screwed into the water pump,but, is it inline when applier to a 351C with a 70 Apm ALT?
Not a lot of clearance in the water pump housing to install it there. Is this a "get-around thing??
" item??[Image: 20190803-122357.jpg]

[Image: 20190803-122443.jpg]
I have three 73 and have nothing like that inline. There is one inline on the heater hose that turns the flow on and off to prevent freezing up the AC. I have the big alternator and it has the one on front of engine that has 3 vacuum lines to hook up. 
[Image: DSC-0955.jpg]

When a man is in the woods and talks and no women are there is he still wrong??
It's an EGR vacuum control valve. The heater hose is the correct location, as the only other ports on the block are taken up by the PVS valve for the vacuum advance and the temp sensor.

It's a valve that closes when the AC is turned on to stop the hot water from the engine from flowing through the heater coil. If you follow the vacuum line back you will find it hooked up under the dash teed to another line that moves one of the heater flappers.

I didn't like the fact that when closed, it was a dead end for the water flow, and probably water leaked past it into the heater regardless. I bought one from a newer model ford truck that actually redirects that water back so it continues flowing. When there is no vacuum a spring lets the water flow as normal. When vacuum is applied, the valve toggles and the water is directed back as the return.

[Image: P1060007.jpg]


73 ragtop, 1999 Mustang Bright Atlantic Blue Paint, Phoenix Engine 302-335HP,  Edelbrock Carb & Performer manifold; c4 with 2000 stall and shiftkit; 3:55 auburn limited slip differential, Hedman shorties; Car Chemistry Exhaust

Classic Air; Tilt Steering Wheel; 1999 Chrysler Sebring bucket Seats ; power windows;
Thanks Hemikiller for the part ID and location info. Was searching so much I was getting myself confused and distracted.

Found a diagram for calibration 3-15A on this site which matches my engine tag, that showed the 2 port switch going to the EGR but not where it went. I do not have the 3 port PVS on my vehicle though. The port on the waterpump has a plug in it. Instead I have the Distributor Vacuum Advance Control shown on the diagram that switches between ported and manifold vacuum to the advance of the dizzy. It is mounted way in the back by the EGR. It looks mechanical and not temp actuated?? Screws and springs?? All my stuff has been disconnected for decades.
I did find a pic of a similar setup online today. (Posted Here) Shows the two valves I have and no 3 port PVS. Is this setup just for 1973? Q Codes? 4 Speed MT? Dual Vac Dizzy? Somewhere an Engineer made this up for a reason???
I will lay out my lines and post just to see if I am even close.
Thanks Again.
This is NOT mine.....
[Image: Inked-Markup-LI.jpg]
 So here is what I think I need to do. Will do a rough layout of vac lines in a bit and let you folks see if I am anywhere close to how lines should be run.
Still not sure which side of a 4300D is ported for the advance and which would be for the EGR. Anything helps.

 [Image: Current-Vac-Diagram.jpg]
So after screwing off all day at work thinking about this, here is what I believe should be the connections. By all means everyone should correct me if I have my head...you know where. Please keep in mind that hose sizes, lengths and routing is NOT the finished product.[Image: 20190803-124712.jpg]

[Image: 20190803-124728.jpg]

[Image: 20190803-124647.jpg]
On my 73 351C 2v there are two Ported Vacuum Switches (PVS). One with two vacuum hose connections (like yours) and another with three connections.  The three-port is in the water pump or a thread port on the thermostat housing (I used a 351M/400 thermostat housing for a port PVS to eliminate the inline heater hose pipe connector) and the two is in the inline heater hose connector that you have. Your 4v diagram only shows the two-port PVS. 

BTW there are two different types of these inline heater hose pipe connectors... the one you have is for Non-A/C cars and the other is a  "H" pipe connector type for factory A/C cars. If you add A/C with a Heater control valve, you may need to use an H-pipe instead of a non-A/C type single pipe connector like you have.

[Image: 351-C-VACCTRL.jpg]

[Image: Heater-Hose-H-Pipe-For-A-C-D3-OZ-18-B402-B-1.jpg]

[Image: Manifold-Vac-Hose-Fitting-Rear-Labeled-A.jpg]
So what I see down on the waterpump, between the heater hoses, is that where the 3 port PVS would be? I have a solid plug there.
(08-06-2019, 03:54 PM)kingb1973 Wrote: So what I see down on the waterpump, between the heater hoses, is that where the 3 port PVS would be? I have a solid plug there.

Yes, the threaded port below the hose nipple on the water pump is for the PVS unit. You should be able to unscrew the plug and swap in the PVS.

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