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I've got a 2007 Hyundai Elantra that's got a mostly-functional AC, but consistently blows warm air when at lower speeds (or idle) on warm days.

So far, I've tested the following:

  1. I press the A/C button and I see under the hood that the clutch starts/stops spinning
  2. When I drive on the freeway, the A/C blows cold 100% of the time
  3. When I coast downhill at around 40 mph, the A/C begins to blow cold
  4. I got one of those all-in-one A/C refill canisters from O'Reilly and before I even tried to add refrigerant in there, the gauge told me the pressure is normal (so I ended up returning the refill canister)
  5. The condenser fan sounds louder than I would expect (compared to my other vehicles -- a minivan and a V8 truck)

Another thing I noticed just the other day is that when idling in my driveway, the A/C clutch stops/starts randomly -- I'm not sure if this is a sign of a bad clutch, or something thermostat-triggered.

I'm starting to think that the condenser fan needs to be replaced. Would you agree? Or should I swap out the entire compressor (since swapping out the clutch would basically require removing the compressor anyways)?

richyen
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2 Answers2

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A couple of things ... is there anything obstructing the air flow through the condenser? Like a plastic bag or something. Rapid clicking of the A/C clutch is usually an indication there is a low refrigerant charge. If you haven't looked at both high/low side readings, while compensating for ambient temperatures, then you don't really know if your charge is low or not. If you don't have a manifold gauge which will show you both pressures, you should take it to an A/C shop to have it tested.

Pᴀᴜʟsᴛᴇʀ2
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I was able to resolve the warm AC by replacing the condenser fan. After replacing it, I noticed the new one (which I pulled out of a 2010 Elantra) was much quieter. I also noticed that the old one had a thermocouple that looked cracked and crusty -- that was probably contributing to incorrect readings, and I assume probably caused the compressor clutch to disengage at wrong times.

I didn't get to fully test @X-tech2's suggestion, but that may have been a possibility. I noticed that after installing the new fan the air blows inward; not sure if my memory is playing tricks on me, but I do recall the old fan blowing outward, so yeah maybe @X-tech2 was right about that. The cracked thermocouple looks like it needs to be replaced anyways, and it runs loud, so I'm not going to bother fixing the orientation of that old fan.

richyen
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