Confused on Heater Control Valve for 1975 Duster 360

[shanker]

I'm in the process of swapping a Eddy RPM Air-Gap onto my wife's Duster (Factory 360 car with A/C and Cruise)

I spent a few hours searching online for proper heater hose routing last night which I finally figured out (I also have both 1975 Factory Service Manuals but they're a little generic and don't have specifics for a Duster 360).

I ended up ordering this one as a backup:
https://www.amazon.com/gp/product/B003R33QZS/?tag=fabo03-20
and one of these:
1975-1976 Chrysler Plymouth ,dodge heater control valve 3846381 | eBay

The one that was on the car is the one I attached a picture of which appears like the one shown in some images of 72-74 cars here.

If I could at least figure out which part number is correct, I'd buy a new/nos one, but I can't seem to identify which one it's supposed to have.

 

[el5dart]

cant really see yours but this looks like the bracket your picture has and has the 30505 number on it.

MOPAR NOS 1975 76 DART VALIANT 1976 CORDOBA FURY A/C & HEATER CONTROL VALVE | eBay

 

[myduster360]

When I got it, my 1974 Duster 360 was 99% original. It came with a valve that bolted to the fender.

It Looked like this. (The pic comes up when your part number 3503487) is searched.)

When it stopped working in the 2000s, I replaced it with the Amazon version you show. seen here hanging from a hose.

Both valves you show will work and be 100% functional.

 

[shanker]

When I got it, my 1974 Duster 360 was 99% original. It came with a valve that bolted to the fender.

It Looked like this. (The pic comes up when your part number 3503487) is searched.)
View attachment 1715616235
When it stopped working in the 2000s, I replaced it with the Amazon version you show. seen here hanging from a hose.

Both valves you show will work and be 100% functional.

(cool serpentine setup you've got there )
then that has me back to being confused about the heater hose routing. On the heater core coming out of the firewall, the pipe is for 1/2" heater cose (driver side) and the one on the passenger side is for 5/8 heater hose. I was going to run the 1/2" to the heater control valve then on to the water pump (closest to the radiator) and the 5/8 hose directly to the intake manifold nipple. am I wrong there?

 

[myduster360]

(cool serpentine setup you've got there )
then that has me back to being confused about the heater hose routing. On the heater core coming out of the firewall, the pipe is for 1/2" heater cose (driver side) and the one on the passenger side is for 5/8 heater hose. I was going to run the 1/2" to the heater control valve then on to the water pump (closest to the radiator) and the 5/8 hose directly to the intake manifold nipple. am I wrong there?

5/8" to the pump is correct. My 75 Service manual says the 5/8" core nipple is on the Drivers side. But it doesnt matter much really as long as the hose diameters all fit. The control valve just blocks the flow to the core.

The Control valve can block the inlet flow or it can block the outlet flow and its functionally identical.

 

[shanker]

so I mocked it up to try and help myself figure this out.

From the Intake Hose Nipple which is 1/2 to the Heater Control Valve inlet which is 1/2

Then from the Heater Hose Nipple Outlet which is 5/8 to the Heater Core 5/8

Then from the 1/2 Heater Core back to the Water Pump 5/8 Nipple (the silicone heater hose stretch's easy and I can make that happen)

 

[shanker]

I ended up buying this heater valve on eBay too (I bought three of them)

3846483 CHRYSLER 1975 Dodge Dart A C Heather Control Valve New ORIGINAL MOPAR | eBay


all I did was take a 4x4 piece of scrap lumber and the second bend on the bracket I flattened it out and drilled two holes to use the original mounting bolts. It's the EXACT same valve just with a different bracket.


I'm kinda excited about almost being done with the intake swap. I'm ready to go roast some tires (this is my wife's car, literally her first car she's had since she was 16)

 

[mopower440]

wondering why they used these valves anyway? you would think that when you have the heat turned to off on the temp switch that would be all you need to keep the heat from blowing in the car..there had to be some reason they used these valves..?

 

[RedFish]

wondering why they used these valves anyway? you would think that when you have the heat turned to off on the temp switch that would be all you need to keep the heat from blowing in the car..there had to be some reason they used these valves..?

Hot water would make the a/c less effective/efficient. Those without a/c dont have a water cutoff valve.

 

[mopower440]

Hot water would make the a/c less effective/efficient. Those without a/c dont have a water cutoff valve.

ah i see. I didnt have a cut off valve on mine and knew it had one originally and i was wondering if thats why my heater core didnt last.

 

[str12-340]

don't all these cars have a heater control valve??? The AC valve was vacuum controlled and the non-AC had a manual cable? Other wise the heat would be circulating full on hot water even in the middle of summer, You would roast!

 

[RedFish]

don't all these cars have a heater control valve??? The AC valve was vacuum controlled and the non-AC had a manual cable? Other wise the heat would be circulating full on hot water even in the middle of summer, You would roast!

No sir, heat only did not get a water cutoff valve. Hot water circulates through the heater core at all times. The blend door is manually closed at the controller. Some owners do install a hand operated water valve under the hood. Makes the cabin a little bit cooler.