• Welcome to For E Bodies Only !

    We are a community of Plymouth Cuda and Dodge Challenger owners. Join now! Its Free!

Heater Hose Verification

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Good Day, All

I am looking to verify that my heater hoses are properly connected. Any help would be appreciated
-Standing in front of the vehicle looking at the firewall....inlet to the heater core, is it the tube on the driver side or the passenger side?
-Standing in front of the vehicle looking at the water pump housing.....there are two nipples (one closer towards the radiator and one behind towards the distributor). Which is the inlet and which is the outlet?
-Also, I have an aftermarket valve like the one pictured. am I correct in assuming the upper passage is the one that controls the flow to the heater core inlet by opening and closing the valve, and the lower passage is just a flow thru return line from the heater core outlet back to the engine (water pump housing inlet nipple)?

Thanks much

Heater Valve.PNG
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Your absolutely correct......a thousand words indeed. Unfortunately, I forgot to mention that my enginine is a Big Block, so it's configured a bit differently.
Let's see if I can determine the flow from your picture:
1. The hose from the intake next to the thermostat must be the outlet from the engine, connected to the upper passage at the heater control valve, then goes to the passenger side nipple on the core.
This must be the inlet of the heater core.
2. The hose coming from the drive side nipple of the heater core...possibly the outlet, then passing through the lower passage of the heater control valve, to the nipple on the water pump, I would assume to be the inlet back to the engine.

Is that how you see it.....or no?

Thanks....always appreciated
 

Juan Veldez

Well-Known Member
Joined
Jan 1, 2011
Messages
729
Reaction score
286
Location
Nampa, Idaho
Your absolutely correct......a thousand words indeed. Unfortunately, I forgot to mention that my enginine is a Big Block, so it's configured a bit differently.
Let's see if I can determine the flow from your picture:
1. The hose from the intake next to the thermostat must be the outlet from the engine, connected to the upper passage at the heater control valve, then goes to the passenger side nipple on the core.
This must be the inlet of the heater core.
2. The hose coming from the drive side nipple of the heater core...possibly the outlet, then passing through the lower passage of the heater control valve, to the nipple on the water pump, I would assume to be the inlet back to the engine.

Is that how you see it.....or no?

Thanks....always appreciated
Air Box seal.jpg
For my small block setup, based on the manual, the smaller hose from the intake port (next to the thermo) goes to that one smaller port on the control valve. It then continues with the larger hose to the top port of the heater core - see attached photo for reference.
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Juan,

Thanks for the pics. They have been very helpful. I believe I can route my hoses similar to yours.
I am grateful for your time and assistance.🤜
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Sooooo,
I connected my hoses like yours, but the engine did not like that. It ran hot and a lot of coolant came through the overflow tube. I think I will switch it back to how I had it before. On the heater core, with both the nipples being the same size, does it really matter which is the inlet and which is the outlet? If anyone can tell me which is which, I think I will be OK.

Thx
 

Juan Veldez

Well-Known Member
Joined
Jan 1, 2011
Messages
729
Reaction score
286
Location
Nampa, Idaho
Sooooo,
I connected my hoses like yours, but the engine did not like that. It ran hot and a lot of coolant came through the overflow tube. I think I will switch it back to how I had it before. On the heater core, with both the nipples being the same size, does it really matter which is the inlet and which is the outlet? If anyone can tell me which is which, I think I will be OK.

Thx
Not sure it really matters, but since the radiator has the hot water directed to the top , drains through, and exits the bottom, I assume (hate that word) the heater core would be treated the same way. Did you maybe overfill the system causing it to hit the overflow? Do you have the control valve open so the water circulates and gets any air pockets out?
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
I don't recal if the valve was open or not. Yesterday I drained more than a gallon so I could switch the hose today. I had the engine running when I put the coolant back in. I left the cap off so that any air bubbles could escape. Will have to work with it and see what I can do.
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Not sure it really matters, but since the radiator has the hot water directed to the top , drains through, and exits the bottom, I assume (hate that word) the heater core would be treated the same way. Did you maybe overfill the system causing it to hit the overflow? Do you have the control valve open so the water circulates and gets any air pockets out?
From what I have read online, the heater core should flow from the bottom up. It helps to remove any air that may be trapped in the system. Now comes the fun part. I searching heater cores and have found two different configurations. One will have the left (inlet) tube that goes to the bottom of the core, and the other will have the right (inlet) tube that goes to the bottom of the core. They will each fit and function properly when installed correctly. The trick is that you have to be aware which one you have before you install it so you will know if it is the left or the right tube that is the inlet. Otherwise, you will do like me, second guess yourself and having coolant flow out of the radiator when and where is shouldn't......:D. Would like to ask you a question. The heater box that you have pictured, was it installed in the vehicle you have pictured?

Thx
 

Juan Veldez

Well-Known Member
Joined
Jan 1, 2011
Messages
729
Reaction score
286
Location
Nampa, Idaho
From what I have read online, the heater core should flow from the bottom up. It helps to remove any air that may be trapped in the system. Now comes the fun part. I searching heater cores and have found two different configurations. One will have the left (inlet) tube that goes to the bottom of the core, and the other will have the right (inlet) tube that goes to the bottom of the core. They will each fit and function properly when installed correctly. The trick is that you have to be aware which one you have before you install it so you will know if it is the left or the right tube that is the inlet. Otherwise, you will do like me, second guess yourself and having coolant flow out of the radiator when and where is shouldn't......:D. Would like to ask you a question. The heater box that you have pictured, was it installed in the vehicle you have pictured?

Thx
Yes, that is my air box with the heater core in it. I re-built it myself.

Per the 1973 Dodge manual, the water line hoses for the small blocks run as I have them installed. I double-triple checked. As far as different input and exiting of the water at the heater core, I have no idea, but since they are only a few inches apart, I don't think it would be highly critical either way, IMO. AND, I do not believe the airbox is any different based on engine size, so then it's just a matter of incoming and out-going direction from your specific motor.
 

sdcbowler

Well-Known Member
Joined
Jun 4, 2015
Messages
161
Reaction score
38
Yes, that is my air box with the heater core in it. I re-built it myself.

Per the 1973 Dodge manual, the water line hoses for the small blocks run as I have them installed. I double-triple checked. As far as different input and exiting of the water at the heater core, I have no idea, but since they are only a few inches apart, I don't think it would be highly critical either way, IMO. AND, I do not believe the airbox is any different based on engine size, so then it's just a matter of incoming and out-going direction from your specific motor.
Got it!
 
Back
Top