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Best way to bypass heaters on a 1956 Cadillac?

Started by carguyblack, July 05, 2019, 11:28:21 AM

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carguyblack

I am experiencing continual heat coming from my kick panels even when the system is supposedly off. No blowers going but pressure air still passes through significantly when the car is under way. I'd like to bypass it for the summer and re-connect (possibly?) when it gets cooler. The issue is that it competes mightily with the a/c system I just got up and running.
2 questions:
1. In the attached diagram, would the best way to do this be to connect line #1 and #2?
2. Would it be best if I blew out all the antifreeze left in the heating system if I'm not going to use it? Should those hoses and radiator cores be flushed so as not corrode?
Thanks for any input.
Chuck
Chuck Dykstra

1956 Sedan DeVille
1956 Coupe DeVille (2 sold)
1957 Oldsmobile 98 (sold)
1989 Bonneville SSE

cadman56

why not just disconnect at the heater cores?
If you are getting air through the kick panels while driving you will probably need to replace the foam panels on all the flappers.  Not hard, I've done it on 3 56's.
Great you got the a/c system working.
1956 Cadillac Coupe deVille (sold)
1956 Cadillac Convertible (sold)
1956 Cadillac Eldorado Seville (sold)
1967 Cadillac Eldorado (sold)
1968 Cadillac Convertible (Sold)
1991 Cadillac Fleetwood Brougham dElegance
Larry Blanchard CLC #5820

V63

Another option, install inline  ‘manual’ shut off valves?

carguyblack

If I were to install inline shut off's, do I need to be concerned about the flow of antifreeze through the engine and radiator or are those heater lines really dedicated just for the heater cores?
Would a shut off valve on each side on the feed lines to the heater cores be sufficient?
Thanks for the suggestion. Seems the way to go as I could turn the flow back on or off a lot easier than re-doing additional hoses.
Chuck Dykstra

1956 Sedan DeVille
1956 Coupe DeVille (2 sold)
1957 Oldsmobile 98 (sold)
1989 Bonneville SSE

carguyblack

Thanks Larry, I'm really happy the a/c works again and appears to have no leaks. For a hot second or longer I thought I really messed things up royally! Lesson learned: Be very careful not to add anything to the flare fitting contact surfaces. Maybe a little sealant on the threads only but even that seems unnecessary.
Chuck Dykstra

1956 Sedan DeVille
1956 Coupe DeVille (2 sold)
1957 Oldsmobile 98 (sold)
1989 Bonneville SSE

cadman56

Another thought, Chuck.  You already know the heater water loop is controller by the water control valve so all you need is a manual shut off valve in the location you have marked as #1.  It should be a 3/4" dia. hose.
the transmission cooler system is essentially what I would call a parrellel loop anhd would ot be affected.
I won't belabor the difficulty of correctly restoring the heater  system of the 56.  You probably already know it is a bear of a beast but I can attest you would never be sorry or afraid to drive it at zero degree outside..
Good luck, I enjoy reading your posts.
1956 Cadillac Coupe deVille (sold)
1956 Cadillac Convertible (sold)
1956 Cadillac Eldorado Seville (sold)
1967 Cadillac Eldorado (sold)
1968 Cadillac Convertible (Sold)
1991 Cadillac Fleetwood Brougham dElegance
Larry Blanchard CLC #5820

carguyblack

Larry,
I added the inline shut off valve this morning like you suggested. Thank you! It then proceeded to rain cats and dogs so i didn't get out with the car to test the lack of heat (I hope!). No reason it shouldn't work out fine so thanks for the suggestion.
It doesn't look very "stock" but who cares? I'll be glad to have non-competing air conditioning once again.

Chuck Dykstra

1956 Sedan DeVille
1956 Coupe DeVille (2 sold)
1957 Oldsmobile 98 (sold)
1989 Bonneville SSE

J. Gomez

Chuck,

Sorry was out of town so couldn’t chime in on your post.   :(

Since you already added the shut-off valves this is just as FYI.

Do you have the line from the water pump going over to the thermostatic valve at the firewall connected to the bottom pipe 90 bent or the top straight pipe?

This line should be at the bottom since the thermostatic valve has the rubber valve sealing the flow inside the straight side pipe. When the heater controls are moved they will press on the valve stem allowing the water to flow through both left and right side heater cores. So there should be no flow between the heater cores with the controls off, unless the rubber valve is bad or if there is corrosion around that could prevent it from sealing.

If the line is connected on the straight side the force of the water pump could force open the valve allowing the flow to go out to both heater cores.

Also, bypassing the thermostatic valve and heater cores is just simple by connecting a piece of heater hose between the inlet and outlet at the water pump.   ;)

Good luck..!
J. Gomez
CLC #23082