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Old Aug 28, 2010 | 03:51 PM
  #1  
dk98classic's Avatar
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From: Smithton, IL
Year: 1998
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Default AC question

I have confirmed the operation of the compressor clutch. Tested the system for pressure. Needs freon. Had a code scan, nothing showed. I am questioning if it is just a low system pressure, low freon, or a possible bad relay or interior selector switch.

Thanks
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Old Aug 28, 2010 | 07:38 PM
  #2  
firstime00XJ's Avatar
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So what exactly is your question? Does your air not blow cold? You just stated what you did, and what you think..........
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Old Aug 28, 2010 | 07:52 PM
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You say the system is low on refrigerant. That is the first place you need to start. These systems only hold 1.25 lbs. of R-134A so it doesn't take much of a leak to make them low and non-functional. If you don't have access to the proper gauges, vac pump and leak tester you might be better off taking it to a shop for diagnosis.

If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.

Jim S
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Old Aug 28, 2010 | 08:14 PM
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CodeXJ's Avatar
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From: Port Orange, FL
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Originally Posted by Catmechanic
You say the system is low on refrigerant. That is the first place you need to start. These systems only hold 1.25 lbs. of R-134A so it doesn't take much of a leak to make them low and non-functional. If you don't have access to the proper gauges, vac pump and leak tester you might be better off taking it to a shop for diagnosis.

If the system is empty vac it down for 15 min, close the valves on the gauges and watch the vacuum on the low side gauge for about 15 min. If it stays steady after the first minute or two it might be normal seepage and just need recharged. If the vacuum drops then you have a leak. You might need to add a partial charge and check with a leak detector. If you don't find any leaks underhood, turn the blower fan on low and use the tester to check the vents. These are known for evaporator coil leaks.

Jim S

Dead on. Even a little loss of coolant will disable the AC, since the AC will detect the pressure as invalid and cut out the compressor in an attempt to save itself, since the coolant is also the lubricant for the compressor.
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Old Aug 28, 2010 | 08:22 PM
  #5  
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Originally Posted by CodeXJ
Dead on. Even a little loss of coolant will disable the AC, since the AC will detect the pressure as invalid and cut out the compressor in an attempt to save itself, since the coolant is also the lubricant for the compressor.
Coolant is what's in the engine and radiator, not the a/c. The a/c has freon/refrigerant in it along with oil. The freon/refrigerant does not lubricate the compressor.... oil does.
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Old Aug 28, 2010 | 09:12 PM
  #6  
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Originally Posted by djb383
Coolant is what's in the engine and radiator, not the a/c. The a/c has freon/refrigerant in it along with oil. The freon/refrigerant does not lubricate the compressor.... oil does.
Ok, refrigerant. My bad, I used the wrong word. And the oil is suspended in the refrigerant, so if you are out of refrigerant, there is no oil. Unless you have a real old school York or similar compressor, of course.
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Old Aug 28, 2010 | 09:17 PM
  #7  
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why is there always a arguement. the guy was close enough.. coolant.. freon refrigerant. close enough. big deal people use different words dude
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Old Aug 29, 2010 | 03:08 PM
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Originally Posted by CodeXJ
Ok, refrigerant. My bad, I used the wrong word. And the oil is suspended in the refrigerant, so if you are out of refrigerant, there is no oil. Unless you have a real old school York or similar compressor, of course.
If oil is suspended in the freon, and that's all u have to do is add freon, why would the FSM say to add X ozs. of PAG oil (for R134A systems) to the compressor, x ozs. of oil to the condenser, x ozs. to the accumulator for a total of x ozs for the entire a/c system? Why would the FSM say to remove the compressor, drain and measure the amount of oil contained in the compressor? Wouldn't it have something to do with adding back the correct amount of oil? How do u get the correct amount of oil? U pour it out of a container, measure it and pour it into the various components of the a/c system. After the correct amount of oil has been added, the system is closed/sealed, a vacuum is pulled to remove air/moisture and x lbs. of refrigerant is added and it all varies by year model.

Some of those a/c quick fix cans at Walmart have oil in them because it was added when the can was filled with refrigerant. Not all cans of refrigerant have oil added to them. R134a systems are very sensitive to the correct amount of oil and pressure as too much oil greatly reduces cooling efficiency and too little oil spells disaster for a compressor, including a old school York.

Wars have gotten started over using the wrong word(s).

Last edited by djb383; Aug 29, 2010 at 03:11 PM.
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Old Jul 5, 2017 | 03:33 PM
  #9  
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I'm kinda having the same issue. my jeep is blowing warm air when i turn on my a/c. I recently took it to a a/c "specialist" and said i had my low and high Freon pressure too high. After setting them correctly. i still have the same issue. checked my clutch, Radiator fan, condenser fan, and noting seems to be wrong. any suggestions?
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