What is this part on water pump elbow for 48 DeSoto?

[MarcDeSoto]

i'm putting my cooling system together getting the engine ready to start for the first time since 1980!  But I can't figure out what this elbow-shaped tube is for.  It's not shown in the shop manual or the Parts Book.  I thought it was probably meant to screw into the heater hole at the rear of the head, but it doesn't fit because the long skinny part just past the thread is too long.  any ideas?  

[MarcDeSoto]

I noticed that this water pump bypass is threaded.  The one on my DeSoto is not.  

[andyd]

The water pump bypass is threaded so that a threaded plug can be screwed into the bypass piece when the heater is not installed.......I have not ever seen that 90degree or elbow shaped piece but I would have a guess and say that it may screw into the bypass fitting to allow a heater hose to connect........andyd 

[MarcDeSoto]

Andy, I think you're right.  What else could it be but a heater hose connection.  Do you know where to buy the heater hose connection at the back of the head?  but it is odd because my old elbow is not threaded and my car does have a heater.  

[andyd]

Marc, sorry I can't be much help re where to get the connection that goes on the head, here in Oz heaters were not a common installation and if installed were usually some sort of aftermarket brand, English "Smiths" was a common brand........I don't know if the attached pic helps but when I installed the heater setup in my 1940 Dodge which has a 318 Poly I used an aftermarket heater water switch which you can just make out between the alternator and front edge of the aircleaner......it screws into the intake manifold in this case and has a cable operated lever which opens or closes the water cock........the thread on the water cock is a standard type which would screw into a cylinder head or an adaptor which itself would screw into the head......where to get this water cock?............I'd try various radiator shops or older spare parts shops or even old wrecking yards..........andyd

[Bryan]

Where pictures come in handy...

[andyd]

Jackpot!........Bryan confirms the elbows use.........andyd

[keithb7]

A cool little elbow for the cab heater circuit. Be sure to seal the threads. 

[desoto1939]

Go to Andy B site he has the threaded shut off value that screws into the head at the hole near the number 6 spark plug.  I use two shut off values one onthe head and the other at the bypass end where the curve pipe would be threaded.

 

reason.  I now can control the entire flow of water to the heater core. so if i have to remove the heater i can turn off the water flow at the rear of the head and at the pump. Now this prevents me from drainng the radiator so that there is no water flow to the heater core.

 

And if the heater core does start to leak I can turn the water off and or just reroute the heater hoses to each end of the shut off valve.

 

GO to ebay and there are several of these valves ranging from 18-35 dollars each.

refer to the below picture of the two shutoff values installed in my 39 Desoto and the routing of the heater hoses. I have had this installed this way for the past 35 years.

Rich Hartung

Desto1939@aol.com

Edited May 11, 2022 by desoto1939

[MarcDeSoto]

So I guess the flow of hot coolant goes first from the head connection to the heater core for hot coolant.  Then after the hot coolant goes through the core, it empties into the hose that takes it back to the bypass elbow.  right?