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1970 Eldorado AC/Heat Overhaul

Started by Anderson, January 23, 2020, 04:41:32 PM

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Anderson

So, I took the Eldorado in for a look-over on the heating/AC today.  Here's what I got back:~
-Control issue to blower
-Partial restriction to heater core
-No temperature control
-Mode only blows from defrost
-Manual shut off valve installed at heater line
-Wiring for blower and clutch has been tampered with

Now, I suspect that some of this was from when the blower was installed to at least get some A/C (which *does* blow cold quite nicely), but the rest is a soup sandwich.  So I think I'm in the market for someone who can un-frak the whole mess (and at this point I'm probably thinking it would be easier to pull and replace than to try and fix things).  Thoughts?  Advice?  Am willing to work with someone in VA or down in FL if you've got a good recommendation.

Bentley

Whoever you choose to work with, make sure you get the Climate Control Manual by Cadillac Tim. It has been a huge help to me and my mechanic.
Wes Bentley
CLC # 30183

"Cadillac Kid" Greg Surfas 15364

WC
You’ve got Scott Minesinger in VA who can straighten it out if anyone can. You say you “took it in”. Does that mean you looked at it or did someone else do that diagnosis? Not meaning to be anything but helpful but is this something (the repairs) that you might want to do yourself?
Although the miles of vacuum lines and the electrical side are complex they are not complicated and taking the issues one at a time is definitely not beyond the average mechanics skill level.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Anderson

I took it to a local shop that was recommended to me for a diagnosis (there was enough "off" that I couldn't even guess...I *did* get the borked heater core right but I hadn't sussed out all of the rest of it).  By the way, as a plot twist, now the blower isn't working.  Thank the gods it's January...I'd probably be going nuclear if they'd borked the blower in July.

I confess that I am disinclined to try and sort out the system...I've never actually worked on a car and I'm terrified of messing up what is otherwise a wonderful, beautiful car, especially since it's looking like the climate control system was probably...I think the term is "Mickey Moused", so it isn't like I'd just be finding one or two things that are out of place.

cadillacmike68

FUBAR'd is the proper term.

Scot M in VA knows a lot about these. If you are in west-central FL,  I know them too. I know the 67-68s better but the 70s are similar.
Regards,
"Cadillac" Mike

Anderson

I'll go with that.  Shot you a PM.

Scot Minesinger

Anderson,

I have fixed about 25 climate control systems on Cadillacs from 1965 thru 1976, and even a 1982.  I own three 1970 Cadillacs and I feel that there is not too much I do not know.  I'm working on 1969 DeVille climate control right now, almost done with it.

My zip code is 22039, and I'm in Fairfax Station, VA (about 20 miles from 14th Street bridge in DC.  Where are you?

I can fix it.

Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

"Cadillac Kid" Greg Surfas 15364

Mike/Scott
If you guys end up with this car I might suggest starting by breaking the ATC into its 5 component systems (heating, cooling ((full refrigeration system functional analysis)), air supply (fan and duct system)), air directional system ((dampers and actuators)) and THEN the control system that directs the action of the previous 4.
It sounds as if someone in the car’s past has modified (read adulterated) one or more of these sub systems.
Just my suggestion for what it is worth.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Anderson

Quote from: Scot Minesinger on January 24, 2020, 08:09:01 PM
Anderson,

I have fixed about 25 climate control systems on Cadillacs from 1965 thru 1976, and even a 1982.  I own three 1970 Cadillacs and I feel that there is not too much I do not know.  I'm working on 1969 DeVille climate control right now, almost done with it.

My zip code is 22039, and I'm in Fairfax Station, VA (about 20 miles from 14th Street bridge in DC.  Where are you?

I can fix it.
I am in Newport News, so it isn't too much of a hike.  I will be out of town for the next few days (going to FL) but as soon as I am back I would be happy to take the car up at your convenience.

Scot Minesinger

People have driven from NJ, about 250 miles from my house for climate control repairs, Newport News is closer.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

R Pope

Scot,
Could I bother you for some AC system advice? My 72 Eldo blows hot air no matter what setting the control unit is set. I can move it from dash vent to floor but in the summer it just adds to the heat! I would greatly appreciate any help in disabling the blower (not sure it is running) or closing of the air inlets if the heat is coming from the engine bay or heater core.

Richard

Scot Minesinger

If your ac worked before, then the controls being repaired will be the most comfortable and economic solution.  If you want to disable the heat then of course you can just by-pass with heater hose.  The programmer is what switches the heat to cool and so that may be at fault.  Or you could have a break in the sensor string, making your system think it is super cold outside.  Did you get any work done recently, such as on sound system? 

To fix your system, I would buy the book from Cadillac Tim and of course the FSM if you have not already.  Then read those.  It is not difficult to test the programmer, do that first.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

R Pope

Thank you. I will get those books and read up. My car was purchased from a person that just wired past, disconnected, or removed the hoses to anything that was not working. The AC has been doing this since I got the car many many years ago. I just stuff small rags in the lower heater vents but need to get serious about fixing it.

"Cadillac Kid" Greg Surfas 15364

Richard
Does your compressor run when the system is operating and if so is the refrigerant charge correct (full site glass)?
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

R Pope

The Freon leaked out pretty quickly the last time I had it charged. Since it is a driver and a convertible getting that fixed came behind lights, seat and window motors, and just undoing all the poor work done before me.
Admittedly I have too many projects and just bounce between them... 1919 Dodge, The Eldo, project Z3, my two kids cars, the wife's, trailers, and on and on...
Trying to refocus on the caddy as the mechanical on the Dodge is now sorted. Needs a new top but that is a major under taking and I will have to teach myself how to sew...that will be interesting.

Richard

"Cadillac Kid" Greg Surfas 15364

Richard
If the refrigerant has leaked out and with it much of the systems oil you will not only be unable to get any cooling but to continue running the system will soon result in compressor failure.
It does sound like your control system is functional since the temperature selector dial seems to have the air delivery sub system cycle. It appears that you need to have the refrigeration system leak checked and leaks repaired. Then proper charging with R12 and you should see some positive results.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

R Pope

Thank you. I will add oil and refrigerant and start there. I have done other AC systems so and have a collection of new seals somewhere.

"Cadillac Kid" Greg Surfas 15364

Be sure and leak check the compressor shaft seal.
Greg surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

R Pope

Richard did disconnect the compressor wiring connector years ago, so hopefully no damage. Now, I certainly can't say how long the PO ran the system ran dry before I tried charging it