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1959 Cadillac Coupe deville heat issue below the dash

Started by ball182star, February 04, 2018, 12:48:44 AM

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ball182star

Hey Everyone,

I purchased a 1959 Cadillac Coupe Deville about a year ago and wanted to see if anyone else has had serious heat coming from below the dash? I can literally feel HEAT coming from below the dash. It feels like everything gets extremely hot (including the metal down there) and i was recommended to put a valve on the the heater line if that makes sense? Any help would be greatly appreciated.

I live in AZ and would like to drive it in the summer but the heat protruding from below the dash is killing me. I purchased the car with an extra A/C blower in the middle of the dash and it blows extremely cold but with the heat coming from behind and around the bottom of the dash it makes the car extremely hot (this coupe has factory A/C). Any ideas on how to cut this out, or what might be the issue? any help is greatly appreciated!

Thank you
Seth Robinson

quadfins

Is the hot air coming out of the normal heater outlets?

There is a valve that regulates (or blocks) the flow of hot coolant into the heater core. if that valve is stuck open, it could be the cause of the Heat-When-You-Don't-Want-It.

If it is just radiant heat from the heater box, it may be a defective valve.

Strange, too, if the heat comes in all the time through the outlets, as warm air should only enter when the actuators allow air in through the core.

Jim

Jim Eccleston
1961 Coupe de Ville
BATILAC
Senior Crown
DeCou Driving Award x 4

David Greenburg

If you haven’t already, I’d make sure the heat valve is in fact closing, the cable isn’t broken, etc.  The easy but ugly fix would be to bypass the heater. Also, get an infrared thermometer at Harbor Freight for $17 and use it to check for inappropriate hot spots.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

James Landi

What is being suggested to you is truly very simple.  Locate the input and return hoses that supply your heater core (that's the miniature aluminium radiator that is mounted inside of your dash and pumping out the heat at your feet)-- those two hoses go through the firewall between the engine space and the cabin.  Splice in a $17.00 ball valve with associated appropriately sized hose barbs that will cut the supply of hot engine coolant to that "miniature aluminium radiator," and shut the valve off.  (Voila--- problem solved)  On those rare  occasions when  you need heat, open the valve.  Or get the heater control fixed as designed by determining just what is wrong with the heat valve and control that is in that line---your choice--- and a decent, honest mechanic can do this for you for under $100 (his/her labor time-- this is simple stuff)--- what ever you decide, there's no reason to suffer with unwanted heat. Happy day, James

59-in-pieces

Seth,
All great ideas of where to look - and there are several.

There is a common thread between the internal air flow baffle doors, and the actual water flow valve on the heater core, and that is cables.
If sliding the control levers in the heater/defrost control assembly on the dash seem soooo easy, likely a cable is broken - normally takes effort to slide
In addition the internal doors/baffles are partly activated by vacuum actuators in the engine compartment attached to the heater box - check the vacuum hoses and suck on hose entering the actuator (aluminum space ship disks) and see if their steel line moves - no movement likely bad actuator - if moves could still be line is broken inside the heater box - unless you notice a change inside the car.

James - elegant work around - rather Rube Goldberg, but can't complain when it works.

Seth, as you do more research, let us know your findings so we may help in zeroing in on the fix.
Have fun,
Steve B.
S. Butcher