Cadillac Seville / Cadillac Eldorado Forum Discussion, '93 Seville A/C problem in Past Cadillac Vehicle Discussion; About two years ago I had the A/C converted over to 134-a. Following the conversion it never got as cold ...
About two years ago I had the A/C converted over to 134-a. Following the conversion it never got as cold as it did with the R-12. As the interior would approach the set temperature I would get a 'Low Refrigerant' message followed by a 'Service A/C soon' message. Checking the refrigerant levels indicated that they were full.
Yesterday I got a new message ' Very Low Refrigerant' followed by 'A/C compressor off' Once again I checked the levels and it appears full. Maybe too full as the gauge I attached to the low side of the system was well into the red.
The compressor won't come on at all. The vehicle has 206,000 miles on it and AFAIK the entire system is original except for the 134-a conversion.
Couldn't really find anything about this in the archives. Suggestions?
Automobile(s): White Diamond '03 DHS (with floor shift)
Re: '93 Seville A/C problem
Just so you understand, the "Very Low Refrigerant" message triggers a Low refrigerant DTC which in turn disables the compressor. The compressor will not run again until the DTC is cleared and then it will only run long enough to recharge the system, otherwise the process will start all over again.
Cleared all the codes and the A/C came back on. Took it to a pro A/C shop and had them check the levels - they were normal. Still getting the "Low Refrigerant' and 'Service A/C soon' messages.
While I was clearing the codes I noticed it listed different settings and parameters in the code section. This got me to wondering: One of those settings has to be the one that triggers the 'Low Refrigerant' message. Since it was originally set up to use R-12 and not 134-A, is there anyway to adjust the sensor setting for the new refrigerant? I asked my mechanic about it and he said 'maybe'.
Since I'm still getting the 'low refrigerant' message it's only a matter of time before the thing cuts out again. There is nothing wrong the the refrigerant levels, the car just thinks that there is. How can I make it understand that everything is okay?
Automobile(s): 1996 El Dorado and 1991 Cheyenne Pickup
Puerto Escondido, Mexico
Re: '93 Seville A/C problem
the low refrigerant message is triggered by the low pressure switch getting activated. nobody can tell for sure if there's the correct amount of refrigerant in the system, since it depends on weight, not pressures. these can indicate if there's too little in the system, but will be fine for quite some range, although there's already refrigerant missing (up to like 50%). when the conversion was done a couple of things should have been changed, too. o-rings, oil, low side pressure switch, at least. r134a behaves different than r12, that includes seeping through the hoses used in r12 systems. that's why you'll loose some of the charge over time, even if everything is sealed up correctly. long story short, have your system recharged and change the low pressure switch. you'll have to live with the system being less powerful (r134a cools less than r12) and having to change refrigerant from time to time because of the seeping issue, unless you change hoses. on the other hand you could use mp39 instead of r12 and not need to convert anything, but that's something i didn't say...
It took a while, but I found the problem. The system had a leak in the evaporator- which of course was behind the dashboard and required massive dis-assembly to repair. Since I was this far into it I also changed out O-rings and the low pressure switch. It's a good thing I REALLY like this car!
That said, it's all done and now blows cold enough to hang meat inside the cabin. Bring on the AZ summer!