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2011 Kia Optima SX
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Discussion Starter #1
Hello,
I searched related issues and so far I have been unable to pinpoint the issue with my A/C system. I'll outline what I have done so far and would appreciate any tips or suggestions. This may not be related to the current issue, but I have always had intermittent issues with the A/C even when the car was new. Sometimes I would turn on the A/C and would get warm air for a few minutes and all of a sudden it would get really cold. I took it to the dealer a couple of times, but they were unable to replicate the issue and I just lived with it. Now I don't get any cold air. This is what I have done so far:
  1. I bought a can of A/C Pro recharge kit and connected it to my low side. I turned on the A/C full blast and the needle was right on the border of low and filled. I added some refrigerant, but it didn't work.
  2. The high side pipe gets hot, but the low side does not cool down.
  3. I checked the evaporator temp sensor and it seemed to be working fine. The resistance I read was around 35C which is close to the ambient temperature.
  4. I have 12 volts going to the compressor's control valve.
  5. I checked the pressure transducer and was reading 61 and 83 psi with the A/C off and on (1.044V and 1.245V)
The compressor seems to be working because the high side is getting hot. Is this a correct assumption? Can the condenser and/or evaporator become clogged?
Thanks,
Ali
 

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2011 KIA Optima SX
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68 Posts
65k on my 11 sx and my compressor went and had to get it replaced. Only had cold air on the highway
 

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09 kia spectra ex,'11 Dodge Journey AWD,04 Chry. T&C, 08 Pontiac G6 gt
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2,513 Posts
From your posting of adding "top up" R-134a....It is possible that the system is overcharged, even from first purchase of the vehicle. BEST way is to have A/C gauges hooked up and see where pressure readings are at and calculated to outside air temp. Most systems are designed to operate with low side pressure at a max of 35 psi at an outside air temp of around 80*. Above that and you will get symptoms as you describe.
This is not posted as the absolute "fix" to your concern, just the best starting point to tracking down the problem, as I've had similar experiences with a number of other vehicles of mine with the same posted concerns.
Good Luck! :)
 

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2011 Kia Optima SX
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Discussion Starter #4
Thank you for your responses. Something happened and now when I turn on the compressor, I hear a loud hissing/swooshing sound from the evaporator.

Does this point to a problem with the charge? I think I may need to bite the bullet and get the system evacuated and recharged.
 

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09 kia spectra ex,'11 Dodge Journey AWD,04 Chry. T&C, 08 Pontiac G6 gt
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2,513 Posts
Again, having proper A/C gages hooked up to the high and lo side ports and getting readings will be the most helpful in tracking down the problem. There are a number of diagnostic steps involved in finding the actual trouble spot of an A/C system. Yes, evacuating and testing timewise for holding system vacuum will determine if recharging will hold or if you have a leak. The evaporator located inside the HVAC box is a common fail point in many makes of vehicles.
 
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