Need A/C Recharge help
Thread Starter
Advanced
Joined: Jul 2004
Posts: 74
Likes: 0
From: Lincolnton North Carolina
Need A/C Recharge help
Has anyone recharged the A/C themselves with the cans of R134A you can buy at any auto parts store? I had one buddy tell me not to because I could overcharge it. Another buddy of mine said you can't overcharge as he says once the A/C is full its full and can't be overcharged. Thanks for the help.
Drifting
Joined: May 2004
Posts: 1,917
Likes: 18
From: Tulsa OK
You can easily recharge yourself, but you CAN overcharge. Buy an A/C pressure guage ($12 at Wal-Mart). Depress the button to let all the pressure out and then, with the car and A/C running, put in a can and check the pressure. Mine only took one can before the pressure was at the specified level on the guage.
Racer
Joined: Jun 2005
Posts: 349
Likes: 0
From: Kevil Ky
Originally Posted by RedRider98
You can easily recharge yourself, but you CAN overcharge. Buy an A/C pressure guage ($12 at Wal-Mart). Depress the button to let all the pressure out and then, with the car and A/C running, put in a can and check the pressure. Mine only took one can before the pressure was at the specified level on the guage.
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
If you charge and use only a suction gauge, charge it to 28 - 32 #'s. More is not always better because you can overcharge. Be sure to purge the air out of the hose prior to connecting to the 134a connector.
I always use dual gauges because if there is a compressor problem or restriction you can see it.
Best of luck.. 99 Nassau Blue
I always use dual gauges because if there is a compressor problem or restriction you can see it.
Best of luck.. 99 Nassau Blue
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Hope you guys have lots of money! 
Adding to much freon will seize the compresser and so will too little, and gage pressures will vary with ambient air temps and % of relative humidity and engine RPM.
Also just letting it all out will not empty the system! It must be evacuated with a vacuum pump down to a specified vacuuum.
And you need to know both the high and low side pressures so the silly f**k'n $12.00 gage sold at Walmart may cost you $$$$$$$$$$$$$$
If your not a Qualified Tech that knows what he's doing with automobile refrigerant systems and have the right tools, let a Pro do it!
JFYI a compresser is about $1200.00 by itself then add the labor of cleaning the system (if it can be done) and the other parts that may be required.
Adding to much freon will seize the compresser and so will too little, and gage pressures will vary with ambient air temps and % of relative humidity and engine RPM.
Also just letting it all out will not empty the system! It must be evacuated with a vacuum pump down to a specified vacuuum.
And you need to know both the high and low side pressures so the silly f**k'n $12.00 gage sold at Walmart may cost you $$$$$$$$$$$$$$
If your not a Qualified Tech that knows what he's doing with automobile refrigerant systems and have the right tools, let a Pro do it!
JFYI a compresser is about $1200.00 by itself then add the labor of cleaning the system (if it can be done) and the other parts that may be required.
Former Vendor
Joined: Apr 2001
Posts: 10,976
Likes: 21
From: FL
St. Jude Donor '13
Originally Posted by corvettebob1
Hope you guys have lots of money!
Adding to much freon will seize the compresser and so will too little, and gage pressures will vary with ambient air temps and % of relative humidity and engine RPM.
Also just letting it all out will not empty the system! It must be evacuated with a vacuum pump down to a specified vacuuum.
And you need to know both the high and low side pressures so the silly f**k'n $12.00 gage sold at Walmart may cost you $$$$$$$$$$$$$$
If your not a Qualified Tech that knows what he's doing with automobile refrigerant systems and have the right tools, let a Pro do it!
JFYI a compresser is about $1200.00 by itself then add the labor of cleaning the system (if it can be done) and the other parts that may be required.
Adding to much freon will seize the compresser and so will too little, and gage pressures will vary with ambient air temps and % of relative humidity and engine RPM.
Also just letting it all out will not empty the system! It must be evacuated with a vacuum pump down to a specified vacuuum.
And you need to know both the high and low side pressures so the silly f**k'n $12.00 gage sold at Walmart may cost you $$$$$$$$$$$$$$
If your not a Qualified Tech that knows what he's doing with automobile refrigerant systems and have the right tools, let a Pro do it!
JFYI a compresser is about $1200.00 by itself then add the labor of cleaning the system (if it can be done) and the other parts that may be required.
Unlike the R12 systems,the days of simply topping the system off are gone.R134 systems are sensitive to capacity for optimum performance.Have a pro evacuate and recharge to the proper capacity 
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
RedRider98's response is correct. This is not rocket science and it just doesn't get any more simple then this procedure. Two precautions: make sure you hook up to the Low Pressure port (that's the fatter line that is cold after running AC), and use a pressure gauge for proper amount of coolant. At the risk of offending some forum members, I just don't understand why some Vette owners are so reluctant to perform routine maintenance themselves and suggest that a "pro" should do this procedure. The dealerships and shops must love you guys.
Drifting
Joined: May 2004
Posts: 1,917
Likes: 18
From: Tulsa OK
Each to his own. All I know is I have charged my Denali, MX-6, and the Vette. I helped my neighbor charge his Tahoe and his F-150. NONE of them have had any problems and blow ice cold air. I charged them up LAST SUMMER.
Last edited by RedRider98; Jun 13, 2005 at 12:46 PM.
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Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
I don't think people are saying you can't do it yourseld but I don't see how it can be done properly without the chart specifying what the pressures should be at given ambient temps and humidities and without using a dual gauge setup. I think the warning is not to just add a can of 134 and hope for the best which is good advice IMO.
Edit: I have the gauges and chart and do my own. Without them though, I would not attempt it.
Edit: I have the gauges and chart and do my own. Without them though, I would not attempt it.
Last edited by 5 Liter Eater; Jun 13, 2005 at 05:19 PM.
Advanced
Joined: Feb 2005
Posts: 69
Likes: 0
From: lambertville mi
a c recharge
if you have broken into the system and lost the charge you have introduced air and moisture and you must evacuate the system. if it's just low and you have a positive pressure on the low side with the system operating you haven't introduced contaminates and can add to the charge. if you have access to a set of 134 gauges add refrigerant until you get about 130 degrees temp, or you can just adjust for comfort trying for 55 degree air temp out of you air ducts, just don't overcharge!!!. if you have opened the system don't try to charge without evac first good luck
tony
tony
Advanced
Joined: Feb 2005
Posts: 69
Likes: 0
From: lambertville mi
need a recharge
quick thought- where did the charge go o-ring? you could add a can of stop leak 134 sometimes it works can you locate the leak? look for oil you may be low on oil also if you find leak with big wet spot
tony
tony
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
Originally Posted by 5 Liter Eater
I don't think people are saying you can't do it yourself but I don't see how it can be done properly without the chart specifying what the pressures should be at given ambient temps and humidities and without using a dual gauge setup. I think the warning is not to just add a can of 134 and hope for the best which is good advice IMO.
I build my own motors fer C's sake! 
But, for example, I'm going to have a GM tech help me with installing a new door weather stripping, because a: it's half art and half science, and b: it's a $250.00 part that you only get "one shot" to do correctly.
My car has never seen the inside of a dealership; I've repaired / replaced / troubleshot BCM's, reverse light switch, edited the PCM w/ HPTuners, designed and manufactured my own CLB, R&R'd my rear subframe / differential for a gear swap, etc. and plan on doing a cam / springs and rocker swap in the near future.
"I just don't understand why some Vette owners are so reluctant to perform routine maintenance themselves and suggest that a "pro" should do this procedure. The dealerships and shops must love you guys."
Be careful about painting pictures of CF folks with such broad strokes.
Last edited by Dan_the_C5_Man; Jun 13, 2005 at 04:51 PM.
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
Originally Posted by Dan_the_C5_Man
:
"I just don't understand why some Vette owners are so reluctant to perform routine maintenance themselves and suggest that a "pro" should do this procedure. The dealerships and shops must love you guys."
Be careful about painting pictures of CF folks with such broad strokes.
"I just don't understand why some Vette owners are so reluctant to perform routine maintenance themselves and suggest that a "pro" should do this procedure. The dealerships and shops must love you guys."
Be careful about painting pictures of CF folks with such broad strokes.
Safety Car
Joined: Nov 2003
Posts: 4,979
Likes: 5
From: San Diego, CA "leaf" "tee" "e"
I have a dual gauge setup, but I only use it to confirm what the cheap gauge tells me. Even then, the cheap gauges seem to be good enough. I'm going to get a vacuum pump to evacuate the system. I've been trying to find out more about R134A systems for a while, and it seems like R134A gets old after a while, and "flushing" the system can help restore the system if it's an old system. It's not that air get's into the system, but the R134A just gets old and less effective.
Either way, the chart is in the manual. I can post up the information from it if anyone wants it. Checking the pressure from the high side port instead of the low side port offers better resolution, but I don't remember if the manual specifies the high side pressure, but 2.2 times the ambient temp is a good starting point.
Either way, the chart is in the manual. I can post up the information from it if anyone wants it. Checking the pressure from the high side port instead of the low side port offers better resolution, but I don't remember if the manual specifies the high side pressure, but 2.2 times the ambient temp is a good starting point.
Team Owner
Joined: Nov 1999
Posts: 26,679
Likes: 17
From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
Originally Posted by tony2003
if you have broken into the system and lost the charge you have introduced air and moisture and you must evacuate the system. if it's just low and you have a positive pressure on the low side with the system operating you haven't introduced contaminates and can add to the charge. if you have access to a set of 134 gauges add refrigerant until you get about 130 degrees temp, or you can just adjust for comfort trying for 55 degree air temp out of you air ducts, just don't overcharge!!!. if you have opened the system don't try to charge without evac first good luck
tony
tony
