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1967 Fleetwood 75-- A/C Not Cold Enoguh

Started by Cadillac Nut, September 15, 2014, 12:28:55 PM

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Cadillac Nut

I have a ’67 Cadillac Fleetwood 75 with Automatic Climate control.  On the front system, everything functions fine except the air isn’t cold enough.  It’s cool but not ice cold like it used to be.  I had the system recharged about a year and half to two years ago, it  had been converted to R134 before I bought it.     Any ideas on this?  It seems strange that it would need a recharge after that short a time.   All other functions on the front system work as they should, the air just needs to be a bit colder. 

On the rear system, it blows only lukewarm air (has always done this since I’ve owned the car), no matter the temperature. (no heat when it's cold either)    Transducer?   Thanks guys for your help! 

Garrett

Scot Minesinger

The front system w/R134, is about a 20% capacity reduction over the r12 refrigerant, and that is how it is.  A larger condenser may improve things.  It should cool you down OK at 90'F and less outside.  Once it gets into the higher 90's not so much, but it is better than no a/c.  The system should not need to be recharged, you must suffer a leak which exacerbates the not cold enough air deal.  My 1970 Cadillac system was charged w/r134 back in 2005 and it is still blowing cold. 

The 71 thru 76 Cadillacs have higher evap air flow and larger condensers so they work real well with r134.

On the back system, yes need more info, could be anything.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Cadillac Nut

Hi,
Thanks.  Sounds like I need to check the system for leaks.  I didn't think it would need a recharge after that short a time.  It's cool but nice that icy cool it used to be.
On the rear system, heat doesn't work or A/C.  Just blows lukewarm air, no matter the outside temperature or where the set the dial.  That's why I thought transducer, it seems like it's not reading the outside temperature.  What other info do you need?

Garrett 

Scot Minesinger

You should buy Cadillac Tim's climate control book.  Google him "Cadillac Tim, Iva SC" it offer a step by step way to fix these systems, I relay on it heavily.  You index to your problem such as fan blows but no conditioned air comes out o vents - just ambient air and his booklists all the possibilities and how to fix them.
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

Garret,
If the system was working to your satisfaction after it was recharged I might suggest having the system checked for proper charge.  The major "source" for leaks is the compressor seal which due to the higher operating pressures with 134a tend to leak more than with R-12.  Also if the system is not "exercised" by running it at least every week, the seal will dry out and leak as well.  The ceramic seals were engineered to operate with Mineral Oil and R-12.  When changing lubricant and refrigerants their sealing characteristics change as well.
It does sound as if the rear system controls are not functioning correctly, but first be sure the refrigerant charge is correct, and you have enough refrigerant in the system for both front and rear.  Regarding the rear heat, be sure before you start any diagnosis to verify the hot water line to the rear system is connected, there are no shut-off valves that are shut off, and the vacuum signal to the rear heating valve is connected and active.
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-

Cadillac Nut

I plan to pick up a copy of Tim's book, it looks excellent.  Thanks.
Greg, thanks for all the info, very helpful.  Didn't occur to me to check the hot water line and vacuum signal.  Something could have been disconnected years ago.