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Hyundai Sonata A/C Issues

2009 Sonata. Several months ago, AC started to not blow cold. First no cold on the drivers side vents while it still blew cold on the passenger side vents for maybe a month, then no cold air on both sides.

I read online that this means the refrigerant was going or gone. I see that I can buy a re-charge kit online for about $60. Should I just buy and try that first and hope that it also fixes whatever leak there is? How would I know that it is not the compressor or whatever belt or the mechanisms that drive the compressor? Do I need to take it to a shop for diagnosis? Or should I just go with trial and error by doing the recharge myself as the first step?

Take it to a shop AC is not DIY.


I also vote to take it to an A/C shop. If you don’t know what you’re doing with these recharge kits, you can damage the system or injure yourself.

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You really need to fix the leak. You need a set of manifold gauges, temp/pressure chart, vacuum pump, dye and/or leak detector, among other tools.
DO replace the receiver/drier if system is opened up.

If it blew cold on one side only, you could have a blend door problem, if that’s how your car works.

Does the entire pulley on the compressor spin with A/C on, or just the part with the belt around it.?

If you DO know what you’re doing, then A/C CAN be a diy job (I am 609 certified), and fixed my Celica’s A/C myself, after having the discharge hose end welded by an A/C shop, changing out the TXP valve, and replacing the pressure switch (switch was leaking at the electrical contacts)

My car is an R12 system, and I didn’t want to convert. IT took me a while to acquire tools, etc. But NO ONE wanted to look at the car (too old, etc). Two years later, the car’s A/C blows cold.

If I had an R134 system I would have had it done at a shop. Lots of money spent on tools, books, etc. So I understand how many people say it’s NOT a DIY job.

That sounds more like a HVAC control problem not a low refrigerant problem.

If the refrigerant were low there wouldn’t be cold air on either side.

Simple thing a DIY’er can do is see if the compressor clutch engages when the AC is turned on.

If the compressor clutch engages, the problem is in the HVAC control system.


Back in the day, and may still exist, there was a refrigerant sight glass.
IF your car has one (someone will know) check this google search for useful info.

Sight glass search

My '79 Celica had a sight glass in the original OEM. When I fixed my A/C, I had several problems (leaking discharge hose, stuck closed TXP valve, and leaking pressure switch), which necessitated changing the receiver/drier. I looked all over for a receiver with a sight glass, there was only one model available, but it didn’t have flare fittings, like my car has. I had to settle for a Four Seasons receiver. Factory Service manual says charge to the “specified amount” of R12 (1.5 lbs), and that’s what I did.