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Right/Wrong way to recharge AC


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So I got the message that I was low on refrigerant and the compressor was shutting down to protect itself. (98 DeVille)

Thought I could handle the re-charge myself, but perhaps not! The kit I am using says that I should connect my line (no problem there), start the car, turn the AC on full blast and begin charging. Problem is, the compressor will only run a few seconds, then shut off. The indicated pressure in the system varies greatly as the compressor shuts off and on in very short cycles.

I had cleared all the codes before attempting, but to no avail.

Is there something wrong with the compressor, or am I just doing this the wrong way? It almost appears I should attempt the re-charge with the car and system turned off, but that's not the way the kit says to do it. Is the "shut off" that the computer went through blocking my attempt to re-charge?

Any clues appreciated...

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You are doing it correctly, but if you charged it with a can of freon and the compressor still doesnt stay on for more than a couple seconds its possible the sensor is bad, thus you are charging a system that could already be charged. Buy a sensor and take it to someone that can capture the freon in the system, you change the sensor (very easy) then have them recharge it.

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Some questions:

Were you able to get a can of refrigerant into the system or is it not drawing it from the can? If it is not drawing it out of the can, there is an issue with the can tap. I used an R-134a can tap for many years and the seals went bad. I bought another tap and it does not work. I have to use my 30 pound cylinder of R-134a.

If the system is pulling in the refrigerant from the can, the compressor operates for a few seconds and then shuts down, check to see if the low refrigerant code is set (current). If it is, you may have a large leak in the system that needs to be repaired. You will then need to use a vacuum pump to evacuate the system and then recharge 2.0 lbs. of refrigerant into the system that is under vacuum.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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  • 3 weeks later...

My only comment is that I have read on this forum that one can bypass the sensor that shuts off the compressor so that you can recharge it yourself.

Don't rely on my comment. Do some research.

Also be aware that sometimes ya need to add lubricant with the freon.

again I am no refrigerant savvy person but if ya have lost alot, you ought to try to make sense of the situation before committing R-12 or whatever you use...but I guess ya already knowd that...

good luck !

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My only comment is that I have read on this forum that one can bypass the sensor that shuts off the compressor so that you can recharge it yourself.

Don't rely on my comment. Do some research.

Also be aware that sometimes ya need to add lubricant with the freon.

again I am no refrigerant savvy person but if ya have lost alot, you ought to try to make sense of the situation before committing R-12 or whatever you use...but I guess ya already knowd that...

good luck !

As it turns out, I had a faulty low pressure sensor. Don't know the mechanics of the AC system. but apparently that was the issue. Took it into the mechanic and explained how I couldn't get the recharge done, and they came back and told me the problem was a faulty/leaky sensor. They replaced it and did the recharge and everything appears to be ok (knock on wood!)

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Good news then, and I hope it stays fixed and the Cadillac blows cold as it should. Thanks for letting us know how you resolved the issue.

Bruce

2023 Cadillac CT4-V Blackwing

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  • 4 weeks later...

Hay Caddy OLtimer, I bought a new small can recharge hose also an it does not fit either, Any Ideas as to why? An can I find a new one to fit?

Thanks, Be Safe

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Hay Caddy OLtimer, I bought a new small can recharge hose also an it does not fit either, Any Ideas as to why? An can I find a new one to fit?

Thanks, Be Safe

What do you mean it won't fit? The hose connector won't attach to the vehicle port? If that is the case, make sure you have the low side fitting - there are two ports on the car. Sometimes, the valve sticks and will not allow the hose to be attached. Briefly depress the valve with a small punch to free it up and the hose should attach.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Correct will not lock over the flange, have cleaned the valve also. it is a plastic coupler on a can of leak detector. I have looked at the brass ones an they seem bigger. Will get one next time I am in town.

Thanks

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  • 6 years later...
On 6/23/2012 at 6:35 PM, the gold2 said:

My only comment is that I have read on this forum that one can bypass the sensor that shuts off the compressor so that you can recharge it yourself.

Don't rely on my comment. Do some research.

Also be aware that sometimes ya need to add lubricant with the freon.

again I am no refrigerant savvy person but if ya have lost alot, you ought to try to make sense of the situation before committing R-12 or whatever you use...but I guess ya already knowd that...

good luck !

Yeah if the compressor is not running continuous during the charge then just disconnect the low side pressure switch connector and ground let's switch out using a paperclip and inserting it into the two holes on the low side pressure switch connector. That will cause the compressor to run continuously while you charge when you're done charging plug the switch plug back in.

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2 hours ago, Dazed0417 said:

Yeah if the compressor is not running continuous during the charge then just disconnect the low side pressure switch connector and ground let's switch out using a paperclip and inserting it into the two holes on the low side pressure switch connector. That will cause the compressor to run continuously while you charge when you're done charging plug the switch plug back in.

You are replying to a 2012 post. 

If the low refrigerant code is on the compressor wont run.  Delete the code and the AC compressor will run.  I would not advise jumping the low pressure switch.  

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

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3 hours ago, Dazed0417 said:

Unless you want to do it right 

Deleting the code is the right way.  Jumping the switch is the wrong way, review the factory service manual.  

In addition, oil is not needed unless a component is replaced, i.e. compressor, drier, etc, the oil is drained out of the component, measured and the same amount of oil added.  Adding too much oil or adding oil willy nilly is not advised.

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

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