2007 Kia Amanti A/C blows Warm

Hello all, I have a 2007 Kia Amanti, 3.8L that I just purchased. It is super clean and only has 50K miles on it but the A/C does not work. I hooked up my manifold gauge and with car off and garage at 71F (22C) both my high and low sides read 71 PSI, so it is not over-charged. With car on and A/C button pressed, the compressor clutch engages and the low sides goes to 52 and high side goes to 90 PSI and they stay there with nearly no movement. Compressor does not cycle and the low side tube is warm and consequently the inside of the car blows even warmer air. I need to figure out if I am dealing with a stuck open expansion valve or a compressor that is gone. What would be the best way to attack this and determine the culprit?
Is it possible that the issue comes from some other part?
I would appreciate your input.

Sounds like a compressor problem it’s not pulling the low side down or causing the high side to go to 200 plus psi

Thanks for your reply Cheryl. It very well could be but I assume a stuck open expansion valve would behave the same way. It won't allow the low side to drop and basically leak the high side pressure into the low side by not having enough restriction. I just don't know how to distinguish one from the other.
If it would be the compressor, do you think it is one of those cases where it has contaminated the whole system with metal shavings or it would be just an internal leak?

Can you get your hands (or better yet, a thermometer) on both lines at the expansion valve? Are they equal temperatures?

Are the high side lines warm/hot all the way from the compressor to the expansion valve?

If you can, I'd be tempted to give the expansion valve a few light taps with the engine running and the compressor engaged. If you suddenly see a change in pressures, you're on the right track.

Hi Tyler,

Sorry for the late reply but I have been waiting for a warmer day to do the test. It has been quite cold in the past few days here in Canada (5C) and the A/C barely needs to kick in so it would not be a fare test. I really like your ideas and will test them out once it gets a bit warmer. I did a quick test as the lines and expansion block are quite accessible but the H and L lines did not get anywhere as warm as they did a few days ago (it was a crazy warm spring day 21C outside), so I decided to postpone your suggestion.
In the meantime any other suggestion would be greatly appreciated as my local shops have not been very helpful. All I hear is, we first need to remove all the Freon and re-fill the system with proper amount and then see what happens. No one seems to want to do a proper diagnosis on the system which to me is a waste of refrigerant and money. I have been to 5 shops and they don't even want to hear my symptoms., "it's probably low on refrigerant, 90% of times that's the problem", "it may have air or crap in it", ... Not a very confidence inspiring diagnosis considering the pressures I saw on the system.

Hi Tyler, sorry for the delay. The weather finally cooperated and I was able to get some readings. I used a laser and tried to get multiple repeatable readings on a warm day 24C (75F). I took the readings in the shade.

Inlet and outlet of expansion valve are both hot/warm (132F and 99F respectively).




The outlet of compressor is super hot (almost cannot touch) laser measures 196F. a little further up it goes down to 144F before the schrader valve.
Right after the schrader valve it drops further to nearly 124/128F.






My low P line around the same area after going through the condenser reads 107F.



Not sure if these are normal readings. Hope it helps diagnose it a bit further.

Hello all, any inputs? Can someone guide me in the right direction please?

Update: I finally caved in and brought the car to a shop. They hooked it up to their snap-on machine and determined that it was low on refrigerant. I was happy to see this and hoped that it was only low on refrigerant. After they evacuated the system, pulled vacuum and refilled to the proper amount it still did not cool at all. Conclusion of the garage was that the compressor is gone.

So the question becomes after I buy a new compressor:

1. Do I need to flush the system? If I remove the desiccant element and it is clean, am I safe to assume the rest of the system is clean and not perform a flush?

2. Do I need to change condenser? I am planning on changing the desiccant element and expansion valve.

3. How do I know how much oil to put in compressor/system with and without flush?
3.a) If I do not flush, I know when we change compressor we are supposed to do oil balance. whatever amount comes out of the old compressor should be put in the new one. but what about the amount lost when the system leaked? oil and refrigerant are mixed so some is lost as the system leaked.
3.b) If I do a flush (lines and evaporator) and change the condenser, do I add the total amount of system oil? half in compressor, half in evaporator?
3.c) If I do a flush and not change condenser, how do I know how much oil to put in.

Knowing the correct amount of oil is so confusing to me.

I would appreciate your input guys. I am trying my best to self-educate and not "F" up in the process. A/C work and components are quite expensive.

The only real way to do this job is to find the leak and flush the system so you can start new with the required oil amount because you have no idea how much is currently in the system. Most condensers these days cannot be flushed and would have to be replaced and same thing with any lines that have mufflers inline. If the refrigerant leak is at a connection somewhere, you will have to replace the o-rings with new ones. You also need a vacuum pump to vacuum down the system.

If the desiccant element is clean you might be good to say that the system is clean unless there is some type of metering device that goes in line before the desiccant that could catch any debris that are in the system.

You are going to have to get some service information on how much oil the system holds. Maybe get a few day subscription to Alldata so you can find the information you need unless you can find the info online somewhere.

A lot of systems hold around 8 ounces of oil but that is only a general idea.

Go to this forum www.autoacforum.com and do some reading and sign up to ask questions. This is where I learned how to do AC repairs as a DIY'er and there are some actual AC techs that frequent that board. Since 2006, I have fixed around 15 vehicles since learning how to do this stuff. I have most of the equipment needed to do these repairs except for a reclaiming machine. I take it somewhere to have it reclaimed if it's my own vehicles and have my friends bring me the vehicle empty or I won't work on it.

I replaced everything in the system on my 1998 Chevy K1500 truck back in 2007 and the system still blows ice cold today.

@ “70monte”, Thank you very much for your detailed and confidence inspiring response. Thank you for the link as well. I will search and see what I can find there.
I do have most equipment needed for the job including a vacuum pump, manifold gauge, PAG oil and refrigerant cans but nothing flush related. I became really hesitant and confused when 3 reputable shops told me that all they need to do is change compressor and that’s it. They did not recommend changing any other component including desiccant, expansion valve or condenser. They said no need to flush either. That’s when I doubted myself.
None of the shops would also answer my question about the amount of oil needed either. They either got offended or told me that their A/C machine knows how much to put it. Nothing about oil balancing,…
I do have the OE service manual for the car but in the section for A/C replacement, there is no mention of flush or changing other components. It mentions oil balancing and the procedure to change compressor. Here is the text:
Install in the reverse order of removal, and note these items.
 If you're installing a new compressor, drain all the refrigerant oil from the removed compressor,
and measure its volume, Subtract the volume of drained oil from 120cc (4.20 oz.) the result is the
amount of oil you should drain from the new compressor (through the suction fitting).

Note that system oil capacity is 150cc+-10. I guess the original Kia compressor comes with a certain amount of oil (Does not mention how much though).
So that’s when I thought, perhaps I am being OCD or have read too much on the net. But your answer confirms what I thought. No real way of knowing how much oil is in the system other than a full flush and new components which will be expensive and labor intensive. Perhaps the shops don’t do it since the customers don’t want to pay as much, “the other shop charges half what you quoted” not knowing what is involved.

I agree that the desiccant would be a good indicator. If it is clean, I will change the compressor only. Do an oil balance, pull vacuum and refill the system. If not, then I have a financial decision to make. In the meantime, any other input would be appreciated.

Sorry for the late reply. I have been out of town on vacation for the past week and just got home today.

Anytime you open up the system, the desiccant bag or whatever they call it for your vehicle should be replaced. Most compressor manufacturers will not warranty the compressor if you don't replace it.

You can buy flush kits at the parts stores. My fiancé's dad used a couple last year when he replaced the compressor and other AC components on his Ford Superduty. He flushed the lines and Evaporator and replaced condenser, compressor, and dryer.