AC questions
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Junior User
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From: Whitewater, CO
AC questions
I just popped an O-ring on my '84 Econoline w/dual AC, right at the dryer. I changed them all. On the rear AC lines, oil was pooling in the lines... A-LOT. If I lowered the line, oil would pour out. Is that an issue?
Also, the sticker says that it should take 4.25# of R12. What would be the correct amount of 134? I put in 3# and my gage shows full pressure. But, it is not cooling as well as it should.
Also, the sticker says that it should take 4.25# of R12. What would be the correct amount of 134? I put in 3# and my gage shows full pressure. But, it is not cooling as well as it should.
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Did you change all the O-rings to R134 compatible O-rings?
R12 vintage O-rings don't usually stand up to R134 refrigerant oil for very long.
Without knowing the service history of an AC system it's impossible to know just how much oil has been put in. Too much oil reduces effiency. It's also a sign previous work sought to help grumpy compressor. Running an R12 system on R134 also reduced efficiency.
For advice it would be better to state what actual PSI your "gage shows" instead of the nebulous "full pressure".
In order to be "cooling as well as it should" the high side should likely be ~300 PSI.
R12 vintage O-rings don't usually stand up to R134 refrigerant oil for very long.
Without knowing the service history of an AC system it's impossible to know just how much oil has been put in. Too much oil reduces effiency. It's also a sign previous work sought to help grumpy compressor. Running an R12 system on R134 also reduced efficiency.
For advice it would be better to state what actual PSI your "gage shows" instead of the nebulous "full pressure".
In order to be "cooling as well as it should" the high side should likely be ~300 PSI.
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Junior User
Joined: Dec 2012
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From: Whitewater, CO
When the O ring popped, I changed them all.
I'm not sure that my gage has the PSI on it. It has a Blue (for low), Green, and then Red. My pressure was at the middle of the Green, in the afternoon, when it was hot out. The next day, I tried it in the am and it was at the bottom of the green. I added 1/2 a can and it works pretty good now.
Thanks for the input.
I'm not sure that my gage has the PSI on it. It has a Blue (for low), Green, and then Red. My pressure was at the middle of the Green, in the afternoon, when it was hot out. The next day, I tried it in the am and it was at the bottom of the green. I added 1/2 a can and it works pretty good now.
Thanks for the input.
Posting Guru
Joined: Feb 2007
Posts: 2,351
Likes: 8
Those simple, low side, DIY charging gauges are OK on systems in good shape, but don't reveal a worn out compressor. You need high side pressure reading to see compressor function & guard against overcharging or blockages.
BII Plow Truck is right about vacuum deairing any system that's been opened up. It's not just air that "will throw everything off" but also the moisture in air.
IMO the best way to tell if "it works pretty good now" is to use an AC thermometer. A good AC system will pull down to ~40F.
BII Plow Truck is right about vacuum deairing any system that's been opened up. It's not just air that "will throw everything off" but also the moisture in air.
IMO the best way to tell if "it works pretty good now" is to use an AC thermometer. A good AC system will pull down to ~40F.
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