winterset Posted September 7, 2008 Report Share Posted September 7, 2008 Decided today to take the car out. First time this summer. I performed my WOT, and I had the AC on since it was a little warm today, and I wanted to exercise the compressor, & slosh around the lubricants in the AC. On my way home, I noticed the AC was on econ. I press auto, & it went to econ. I checked & had an ac1347. before I added 134a, I put a pressure check on the low side, & it was in the red zone reading approx 80!!! I cleared the code, and it was now jumping between 25 and 50 with the compressor staying on for about 2 seconds off for 4 seconds. I added a 14oz can of EZChill (tune up,lubricate,clean & charge) now the system reads a steady 30. My questions for the AC experts: -Should I be concerned about the high reading - is that normal? -Is 30 enough? - and if not, should I only add R134a the next time (no oil)? My gauge has green,blue,yellow,red I am in the blue now. BTW, the AC stays on now, and it blows out cold air. I also want to add that I never had the AC serviced, and I never put my gauge on it. I think the last few years, the compressor has been coming on and off alot. Now that I hear it run & stay running, it's probably behaving the way it should. I suspect I was a little low the lasf few years. - my point is that I suspect it's been a slow leak? Link to comment Share on other sites More sharing options...
Dave in Texas Posted September 7, 2008 Report Share Posted September 7, 2008 Typical low-side pressure will be 31-36 psi (at sea-level with 80dg ambient temp). Blue is a good color, but reading both Low/High side pressures is a better diagnostic tool. 12yrs longevity is very good. Frequent cycling of the compressor is usually a sign of low refrigerant, but there are other possibilities. If the system continues to lose refrigerant: find//fix what is leaking. Do Not introduce any type of 'sealant' into the system. That stuff is, at best, a band-aid and will cause money problems in the end. GM Reman 4.1 engine Dec '08 Link to comment Share on other sites More sharing options...
Ranger Posted September 8, 2008 Report Share Posted September 8, 2008 Needing a refrigerant top off once in 12 years is not uncommon and in fact is pretty darn good. You do not need to add oil unless there is a catastrophic depressurization. Link to comment Share on other sites More sharing options...
WarrenJ Posted September 8, 2008 Report Share Posted September 8, 2008 -Is 30 enough? - and if not, should I only add R134a the next time (no oil)? My gauge has green,blue,yellow,red I am in the blue now. BTW, the AC stays on now, and it blows out cold air. At 30 I'd expect you're slightly on the low side unless you charged on a very cool day. That said, it's best to be a little on the low side as opposed to being on the high side. If you overcharge, the system will blow off any dangerous excess, but that will leave you slightly overcharged. I'd stick with what you've got and only add a little if you notice a decrease in A/C performance. Your system has a capacity of about 2 lbs. If you added 14 oz. were seriously low. Adding refrigerant while monitoring only the low side is a bit of an art. It's better to monitor both high and low side and consult temperature/humidity charts as you charge using both gauges. The only "proper" way to charge is to completely evacuate the system and add the correct measured amount of R134a. And no, please don't use refrigerants with additives. They are only required if you have serious problems, in which case you'd want a professional to do it anyway. Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
winterset Posted July 29, 2009 Author Report Share Posted July 29, 2009 My AC completely stopped working now. not sure when it happened. no codes, it lets me stay in auto mode (when the AC was low, it automatically went to econ). I don't hear the compressor engage at all. I checked the pressure on the low side, and it was in the RED. what should I check first? Link to comment Share on other sites More sharing options...
BodybyFisher Posted July 29, 2009 Report Share Posted July 29, 2009 My AC completely stopped working now. not sure when it happened. no codes, it lets me stay in auto mode (when the AC was low, it automatically went to econ). I don't hear the compressor engage at all. I checked the pressure on the low side, and it was in the RED. what should I check first? No codes means to me that its electrical, check the AC COMP fuse and check the connection at the compressor. If that is good check to see if you have power at the AC COMP fuse and at the compressor plug Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
KHE Posted July 29, 2009 Report Share Posted July 29, 2009 Those low side pressure gages are worse than worthless... The pressure needs to be taken while the compressor is running. When th ecompressor is off, the low side pressure will rise which is normal. If the compressor is off for a short period of time (if you turn it off or the system disables the compressor), the low and high side pressures will equalize to static pressure of 75-90 psi which is normal. If there are not any codes set, it could be something in the power circuit to the clutch coil as stated earlier. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
winterset Posted July 29, 2009 Author Report Share Posted July 29, 2009 thanks KHE. My concern was more with the high reading after I added that can a few months back. I suggested yesterday in another post that someone switch their AC relay with their fuel pump relay to see if their car starts up quicker. Well.... I did the opposite, and my car didn't start. I was never so happy to see my car not start. I switched them back, took my AC relay apart, cleaned the contacts, and as soon as I plugged it in, I heard my compressor engage. I will order a relay now. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.