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AC fix

Old 05-24-2012, 04:59 PM
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SXGT
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Default AC fix

should I have my line professionally evacuated and refilled or should I try to do this myself? can i do this myself? can i just hit the hi side and let it all out and then refill it with a can of 134a?

also what a good price to pay for a shop to do it i dont want to get over charged.

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Old 05-24-2012, 10:07 PM
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Originally Posted by SXGT View Post
should I have my line professionally evacuated and refilled or should I try to do this myself? can i do this myself? can i just hit the hi side and let it all out and then refill it with a can of 134a?

also what a good price to pay for a shop to do it i dont want to get over charged.

"Evacuated" means applying a vacuum of at least 28 inHg (inches of mercury) to the system for 45 to 60 minutes. This causes any water/water vapour in the system to "boil" off and ensure that the AC lines. condenser, evaporator and all are dry--any water in the system is bad, very bad.

Doing this is not magic or rocket science, however you do need a vacuum pump and to do it right a set of R134A gauges. The good news is that you can buy this stuff from Harbor Freight for probably less than an AC shop would charge you to do the job--and you get to keep the tools!

Here is a great vacuum pump from HF (I have one)--$105:



And a gauge set for $55:



So, for $160 you can have all the "magical" tools you need to repair any AC system on any car, fix a few of your neighbor's cars and they will pay you well and elevate you to exalted status that could lead to who knows what...

Also, if the system is flat (as you described) it takes 34 ounces of R134a, a bit less than three 12 oz cans.

If you want to buy the pump and gauges let me know, I can guide you through the process and once again I assure you there is not one bit of magic or rocket science involved...
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Old 05-26-2012, 08:56 AM
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after running with my AC on last night I got out of my car and after it was turned off i could hear a PSSSSTTT sound every 7 or 8 seconds. it wasn't very loud but it sounded like it was coming from my hi side, didnt pop the hood to check, had other things I was doing.


when i hook up my 134a can with gauge it shows I am low then high and then low and then high. the system is clicking on and off every 10 seconds. The AC is cool but not COLD and it goes cool to warm to cool to warm. not so much on the interstate but more so at idle. Its only good for temps in the high 70s as soon as its high 80s and low 90s outside I will be miserable hot and my AC just wont be cold enough.

is this a compressor issue or a freon line issue, does it sound like i have water in my line?
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Old 05-26-2012, 11:24 AM
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96meangreengt
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Originally Posted by SXGT View Post
after running with my AC on last night I got out of my car and after it was turned off i could hear a PSSSSTTT sound every 7 or 8 seconds. it wasn't very loud but it sounded like it was coming from my hi side, didnt pop the hood to check, had other things I was doing.


when i hook up my 134a can with gauge it shows I am low then high and then low and then high. the system is clicking on and off every 10 seconds. The AC is cool but not COLD and it goes cool to warm to cool to warm. not so much on the interstate but more so at idle. Its only good for temps in the high 70s as soon as its high 80s and low 90s outside I will be miserable hot and my AC just wont be cold enough.

is this a compressor issue or a freon line issue, does it sound like i have water in my line?
Sounds like low refrigerant to me.
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Old 05-26-2012, 11:47 AM
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Originally Posted by SXGT View Post
after running with my AC on last night I got out of my car and after it was turned off i could hear a PSSSSTTT sound every 7 or 8 seconds. it wasn't very loud but it sounded like it was coming from my hi side, didnt pop the hood to check, had other things I was doing.


when i hook up my 134a can with gauge it shows I am low then high and then low and then high. the system is clicking on and off every 10 seconds. The AC is cool but not COLD and it goes cool to warm to cool to warm. not so much on the interstate but more so at idle. Its only good for temps in the high 70s as soon as its high 80s and low 90s outside I will be miserable hot and my AC just wont be cold enough.

is this a compressor issue or a freon line issue, does it sound like i have water in my line?
Unless the system was open for some period of time, or improperly serviced (I.e. if it was open and not evacuated prior to charging) there cannot be any water in there.

You need to get a real gauge set, and work the problem from there--speculating as to what the problem might be is just shooting in the dark and hoping you get lucky. One other thing about having the gauge set and some experience is how much you will find your neighbors are willing to pay to have you check their systems. I hardly ever have to buy beer this time of year...

Here is an ambient temperature vs. expected pressure chart:



And here is how to interpret the various "bad" high/low side pressures:



==================================================
BTW/FWIW: R-134a is not Freon. Freon was Dupont's trade name for its chlorofluorocarbon refrigerants (R-11, R-12). R-134a is tetrafluoroethane, Dupont's trade name for it's tetrafluoroethane refrigerants is Suva.

If you really want to baffle most auto air mechanics refer to it as Suva, it is amazing how many of them won't have a clue as to what you are talking about...
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Old 05-27-2012, 11:23 PM
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pfc_gomez
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I just paid $200 to get my ac fixed on the wifeys SUV. I had a crushed line from previous work I had done few months ago thanks to my dads friend "the mechanic". Lesson learned.
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Old 05-31-2012, 10:09 PM
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Old 06-01-2012, 07:22 AM
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Originally Posted by SXGT View Post
When that video was made were the windows down/doors open and the blower on high? You need to force the AC to not cycle.

If it was made with the doors open and blower on high, then you need a real R134a gauge set to properly diagnose the system--the twiddly little low side gauge that came with the FLAPS recharge kit is intended only for "topping off" an otherwise correctly operating system--it is not a diagnostic tool...
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Old 06-01-2012, 07:53 AM
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Originally Posted by cliffyk View Post
"Evacuated" means applying a vacuum of at least 28 inHg (inches of mercury) to the system for 45 to 60 minutes. This causes any water/water vapour in the system to "boil" off and ensure that the AC lines. condenser, evaporator and all are dry--any water in the system is bad, very bad.

Doing this is not magic or rocket science, however you do need a vacuum pump and to do it right a set of R134A gauges. The good news is that you can buy this stuff from Harbor Freight for probably less than an AC shop would charge you to do the job--and you get to keep the tools!

Here is a great vacuum pump from HF (I have one)--$105:



And a gauge set for $55:



So, for $160 you can have all the "magical" tools you need to repair any AC system on any car, fix a few of your neighbor's cars and they will pay you well and elevate you to exalted status that could lead to who knows what...

Also, if the system is flat (as you described) it takes 34 ounces of R134a, a bit less than three 12 oz cans.

If you want to buy the pump and gauges let me know, I can guide you through the process and once again I assure you there is not one bit of magic or rocket science involved...
This is something I'd love to know how to do. I can't believe Im the first person to bite on a very intriguing invitation to learn from an AC master. Especially one that can teach us how to fish for beer.
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Old 06-01-2012, 08:31 AM
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I am not generally a big fan of Haynes manuals, they're OK and better than no manual but that's about it--however their
Automotive HVAC manual Automotive HVAC manual
provides a good base knowledge for repairing most all mobile systems.

Here is the Climate Control System diagnosis and testing section from the shop manual--read them both and you should be all set, give me a yell if you get stuck...
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