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Old 04-07-2002, 08:06 PM   #1
RipMeyer
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Post How Long Does A Recharge Last On A/C

How Long Does A Recharge Last On A/C With Moderate Use?

Does it matter what kind of coolent is used?
R12 - R134?
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Old 04-07-2002, 08:19 PM   #2
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Air Conditioning is a "sealed" system. If everything is in good working order it should not need to be charged. However over time some components will begin to deteriorate internally which will affect how the system works.
R12 and R134a are not compatable, they can not be used with one another efficiently
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Old 04-07-2002, 08:26 PM   #3
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Thanks

I am aware of the R12 and R134 not being compatable, I was wondering if one lasted longer than the other.


I have R12 now, Mine seems to work just fine and blows fairly cold However, Would 1 small can be enough to top it up so to speak? And how much is a small can nowadays?
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Old 04-07-2002, 08:39 PM   #4
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I put in a new receiver/dryer and new o-rings in my '72 Malibu in the summer of 1989. I topped off the system on my '71 Malibu that same year.
In other words if you have a system without any leaks you shouldn't have to put so much in every so often.
I have read that when the thermometer dips below -20 or -22 F or so you get "winter kill" in your R12 system. When the temp dips below that number your system depressurizes and some R12 escapes. Like I said I've read it and I think I've even heard it on a radio call in car talk show before but I know my cars have been in temps below that in the 10+ years since I've topped them off and they are still working fine.
If your truck never sees those temps you got a leak.
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Old 04-07-2002, 08:45 PM   #5
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Rip, you got any AC techs that can help you?

The reason I ask is you really need to put gauges on that system to check proper charge, system condition, etc.

Without the gauge readings its just a "shot in the dark" as to how much refrigerant is in the system.
I know this doesn't help much but even though many people charge AC systems, there are chemical reactions that take place which produce products that slowly "eat away" at the system if not handled properly
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Old 04-07-2002, 08:58 PM   #6
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All a/c systems leak always.(on a molecular level). Just like the air pressure in your tires.
The amount of pressure in the system is directly related to the ambiant temp.The hotter it is out side the higher the pressure in the system. There is a formula for calculating what the high and low pressures should read on your system based on ambient temp.(have in a book somewhere).
The worst enemy of your system moisture.
The reaction of chlorofluorocarbons to moisture is hydrocloric asid.that is why if an a/c system has been exposed to outside atmosperes(no freon),you can get what looks like battery acid on the fitting and in side the system.

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Old 04-07-2002, 09:19 PM   #7
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The oil absorbs the moisture and turns to acid! Poly ester oil which is used on 134a has a very high absorbtion rate and will turn to an acid that will affect your skin in a minor burn! This is a sealed system and as long as its a good sealed system you should not have to add any refrigerant. R12 and 134a are very much alike pressure respect. If your system does have a leak a good hot day your refrigerant will find it. You can add refrigerant til pressures are correct but to make sure you have a correct charge you should Recover what is in the system weigh it and if its low pump up with nitrogen and search for leaks. Repair leak and charge to factory specs. When systems sit not being in operation, the suction side of the system contains a higher pressure and can find small leaks and escape. Most likely in residential Air conditioning when system are not being used in the winter time!

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Old 04-07-2002, 09:31 PM   #8
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If you dont have the gauges etc i wouldnt do it,my stepdad has a bunch of r12 cans thought hed add some well he did and it was too much-ruined the compressor.
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Old 04-07-2002, 09:34 PM   #9
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I heard r12 cools better,but ive never had both to compare-just what ive heard-but it is alot more spendy-and it shouldnt take much to cool off the inside of a cab,its a small area to cool.long as you have good weatherstrip and no big rustholes in the firewall-make sure that cab is sealed up good.
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Old 04-07-2002, 10:39 PM   #10
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The A/C works great. I was just wondering if it needed any attention or preventive maintenance in the very near future.

Thanks For the Replys
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Old 04-08-2002, 12:50 AM   #11
Andy4639
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Cool

Run your system every once in a while during the winter to keep the system going and o-rings lubed, and it will last a lot longer. If you don't have the gauges wouldn't try and top off the system.

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Old 04-08-2002, 02:56 AM   #12
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As long as it's cold, you shouldn't need any.

I know mine needs some (I've got gauges and a stash of R12 my dad snagged while it was cheap, woo!) since it's historically needed about a can a year...but now I think it needs more, it's never been this warm at the start of a summer...

Eh, either way, I'll run R12 until I run out of it, then rebuild the system and go R134a.

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