heater hose routing

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Sep 30, 2010
Messages
6,146
Reaction score
1,109
Location
Mustang, OK.
My Car
1972 Mach 1 Q code
2007 GT
1969 Cougar Eliminator B302
CSX 7000 Shelby Cobra FIA
2020 Edge ST
2002 F250 V10
Anyone have pictures or diagrams of heater hose routing, with control valve (AC car) for 351C? all help appreciated.

Chuck

 
i can show you how i ran mine, the ford shop manual isn't a great help.

If you have a different intake and air cleaner base things will get in the way also.

an ac car.

ok the heater core has 2 connections, looking from the front of the car to the firewall i will call it left and right. left is towards the shock tower, and right is towards the engine.

off the right connection you will need a small piece of S shaped hose.

HH12.jpg


http://mustangsunlimited.com/itemdy00.asp?T1=HH12+01

connect one end into the heater core, bring the other up behind the motor, and connect the control valve to it.

the heater hose:

HH7AC.jpg


http://mustangsunlimited.com/itemdy00.asp?T1=HH7AC+01

now one heater hose is molded with a L the other is straight. depending on how your intake and air cleaner base and alternator all sit, you may have to juggle things around, basically the L shape goes into the water pump, and the other hose which is straight can go either way.

which port you use doesn't matter it will depend on how everything sits so mock things up first then cut until your happy with how everything fits.

the manual wants you to run both hoses over the motor on the left side underneath the air cleaner base. between the heat riser. this isn't practical because of all the changes to the car over the years. I ran my heater control valve hose (one hose) over the engine between the air base and the heat riser. The other hose i let go around the side of the engine by the shock tower following the A/C hoses to make things easier to service because i was taking the air cleaner base on and off the car all the time. it looks fairly neat.

once you change the intake and the carb from OEM, the spacing gets REALLY tight running both hoses there causes issues. i also have my fuel line coming up in that area to get to my Holley DP and having both hoses there would of caused a problem with that also.

here is a diagram

acdiagram.jpg


tonight i'll see if i have some pictures of my car.

one word of caution with the molded hoses from any vendor, I've noticed they can be defective. i had a set of heater hoses with the yellow stripe and on the side of the hose is a ribbed area to make them look concourse correct, i found them to have Pin hole leaks from that area. I had to change heater hoses 2 times before i received a set that was not defective. I've learned that that type of hose from 'Marti' are made in a mold to match OEM and they can be defective.

so if you change hoses and see coolant under the car, run your hand to the lowest part of the heater hose and if its wet change the entire hose its defective.

 
i can show you how i ran mine, the ford shop manual isn't a great help.

If you have a different intake and air cleaner base things will get in the way also.

an ac car.

ok the heater core has 2 connections, looking from the front of the car to the firewall i will call it left and right. left is towards the shock tower, and right is towards the engine.

off the right connection you will need a small piece of S shaped hose.

HH12.jpg


http://mustangsunlimited.com/itemdy00.asp?T1=HH12+01

connect one end into the heater core, bring the other up behind the motor, and connect the control valve to it.

the heater hose:

HH7AC.jpg


http://mustangsunlimited.com/itemdy00.asp?T1=HH7AC+01

now one heater hose is molded with a L the other is straight. depending on how your intake and air cleaner base and alternator all sit, you may have to juggle things around, basically the L shape goes into the water pump, and the other hose which is straight can go either way.

which port you use doesn't matter it will depend on how everything sits so mock things up first then cut until your happy with how everything fits.

the manual wants you to run both hoses over the motor on the left side underneath the air cleaner base. between the heat riser. this isn't practical because of all the changes to the car over the years. I ran my heater control valve hose (one hose) over the engine between the air base and the heat riser. The other hose i let go around the side of the engine by the shock tower following the A/C hoses to make things easier to service because i was taking the air cleaner base on and off the car all the time. it looks fairly neat.

once you change the intake and the carb from OEM, the spacing gets REALLY tight running both hoses there causes issues. i also have my fuel line coming up in that area to get to my Holley DP and having both hoses there would of caused a problem with that also.

here is a diagram

acdiagram.jpg


tonight i'll see if i have some pictures of my car.

one word of caution with the molded hoses from any vendor, I've noticed they can be defective. i had a set of heater hoses with the yellow stripe and on the side of the hose is a ribbed area to make them look concourse correct, i found them to have Pin hole leaks from that area. I had to change heater hoses 2 times before i received a set that was not defective. I've learned that that type of hose from 'Marti' are made in a mold to match OEM and they can be defective.

so if you change hoses and see coolant under the car, run your hand to the lowest part of the heater hose and if its wet change the entire hose its defective.
Thank you for the information. The pictures will be great. The assembly manual wasn't of much help. It doesn't show the vacuum actuated heater control valve at all and it shows the "inlet" to be on the outboard side and the "outlet" to be on the inboard side.

Thanks Again, Chuck

 
Its been shown not to matter how the heater box is hooked up to the water pump so long as the valve closes off one side of the feed to the water pump it basically turns the heater core off.

on earlier cars before 1970 there is suppose to be a difference because of a restrictor used before the heater core to prevent a pressure build up inside the core which can cause the heatercore to actually blow up.

so in that case with the hipo engines you needed to make sure the connection was correct. on 71-73 is does not seem to mater.

 
Its been shown not to matter how the heater box is hooked up to the water pump so long as the valve closes off one side of the feed to the water pump it basically turns the heater core off.

on earlier cars before 1970 there is suppose to be a difference because of a restrictor used before the heater core to prevent a pressure build up inside the core which can cause the heatercore to actually blow up.

so in that case with the hipo engines you needed to make sure the connection was correct. on 71-73 is does not seem to mater.

Thanks for your help. Chuck

 
went through the pics on my harddrive and never really took a picture of the area completed, it will be difficult to get a shot because the shock tower braces, and aircleaner and my carb are all blocking the views. i'll make a drawing of where my L hose is so you can get an idea when you mock yours up.

 
went through the pics on my harddrive and never really took a picture of the area completed, it will be difficult to get a shot because the shock tower braces, and aircleaner and my carb are all blocking the views. i'll make a drawing of where my L hose is so you can get an idea when you mock yours up.
Thanks. I appreciate it. Chuck

 
Last edited by a moderator:
Didn't know if this would help or not. The inboard hose between the heater control valve and firewall should be about 8 inches to clear the valve cover. The one in the pic is 6 inches. What do you need to know exactly. Mark

http://i841.photobucket.com/albums/zz340/machman_73/IMG_0703-1.jpg
Mark, Thanks for helping. The issue is lots of information that is contradictory. The assembly manual (I've found errors before) shows coolant entering the outboard heater core fitting and returning to the engine from the inboard fitting. But the drawing I have doesn't show a heater control valve (I know there was one on AC cars). It seems to me that the heater control valve should block the flow of coolant entering the heater core. However, I'm almost certain the control valve attaches to the inboard fitting (as in your pic) via short S shaped formed hose. This contradicts the Ford drawing. The other end of that hose goes to the fitting in the block next to the thermostat outlet (supply, I think). The outboard heater core hose connects to the fitting on the water pump (return, I think). I have spent hours trying to sort out what is actually correct. All help appreciated.

Thanks, Chuck

 
just remember the direction of coolant doesn't matter as long as the heater control valve stops one side of flow into the core.

the easiest is hooking the right side of the heater core straight to the top fitting on the water pump(putting the heater control valve in between)

then the left side of the heater core to the left side of the water pump

this makes the most sense since the S hose helps clear the back of the motor to allow you to run the heater hose on the left side of the intake between the carb and the heat riser.

also the vacuum line from 71-72 coming out of the dash is short so it makes sense to put the control valve on the right side.

the picture posted is a 73, 73 has that vacuum tree on the cowl area because it needed to feed the EGR valve. and to clean up the look of the manifold a little.

 
just remember the direction of coolant doesn't matter as long as the heater control valve stops one side of flow into the core.

the easiest is hooking the right side of the heater core straight to the top fitting on the water pump(putting the heater control valve in between)

then the left side of the heater core to the left side of the water pump

this makes the most sense since the S hose helps clear the back of the motor to allow you to run the heater hose on the left side of the intake between the carb and the heat riser.

also the vacuum line from 71-72 coming out of the dash is short so it makes sense to put the control valve on the right side.

the picture posted is a 73, 73 has that vacuum tree on the cowl area because it needed to feed the EGR valve. and to clean up the look of the manifold a little.
That is how I decided to route the hoses for the reasons you stated. I appreciate your help.

Thanks, Chuck

 
Here are a pics of my 73 351C factory air car. You can see the route and the heater valve on the hose with the "S" tube. What you can't see in the pic is that the hoses are strapped to the shock tower to ensure the clear the engine.



Also, my 73 came with an "H" tube which I did not reinstall. It was used to provide a port for a PVS vacuum valve. The "H" tube was inserted/installed just after the heater hoses passed the oil dip stick.



 
Last edited by a moderator:
Here are a pics of my 73 351C factory air car. You can see the route and the heater valve on the hose with the "S" tube. What you can't see in the pic is that the hoses are strapped to the shock tower to ensure the clear the engine.



Also, my 73 came with an "H" tube which I did not reinstall. It was used to provide a port for a PVS vacuum valve. The "H" tube was inserted/installed just after the heater hoses passed the oil dip stick.

Racherm what was the  purpose of the H tube. My 73 Q code had the same fitting and it starting leaking right after I bought the car 6 years ago so I removed it.

John J

 
Here are a pics of my 73 351C factory air car. You can see the route and the heater valve on the hose with the "S" tube. What you can't see in the pic is that the hoses are strapped to the shock tower to ensure the clear the engine.



Also, my 73 came with an "H" tube which I did not reinstall. It was used to provide a port for a PVS vacuum valve. The "H" tube was inserted/installed just after the heater hoses passed the oil dip stick.

Racherm what was the  purpose of the H tube. My 73 Q code had the same fitting and it starting leaking right after I bought the car 6 years ago so I removed it.

John J
I believe it was needed to add a heat sensite port. Three ports were needed for the temp sender, the two port pvs and three port pvs vacuum valves. The temp sender and one pvs valve were installed in the two ports at/in the water pump. The "H" tube provided the third. Altgough not factory correct, I eliminated the "H" tube as well and used a cast iron





thermostat housing with a port instead. The pics below show the location of the temp sender and the two PVS valves.

 
Back
Top