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Discussion Starter · #1 ·
Yesterday I got in my 2010 Chevy Cobalt after it sat for over a month. It was hot out, but my AC would only blow warm air. So first I checked the fuse and relay and both were fine. Then I checked to make sure the AC clutch was engaged and it was, so I figured it must need to be re-charged. I bought a can of AC Pro and hooked it up to the low charge port, but it showed in the green which the can said it didn't need recharging. The AC lines do not feel cold. Does this mean my compressor may be shot? How can I diagnose a bad compressor or what can I check next? Thanks.
 

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Yesterday I got in my 2010 Chevy Cobalt after it sat for over a month. It was hot out, but my AC would only blow warm air. So first I checked the fuse and relay and both were fine. Then I checked to make sure the AC clutch was engaged and it was, so I figured it must need to be re-charged. I bought a can of AC Pro and hooked it up to the low charge port, but it showed in the green which the can said it didn't need recharging. The AC lines do not feel cold. Does this mean my compressor may be shot? How can I diagnose a bad compressor or what can I check next? Thanks.
Did you turn on the A/C?
Did you try turning the temperature knob from hot to cold?
 

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AC Line clog maybe, take it somewhere cheap and get a diagnosis before you spend money. It is a big possibility that the compressor is bad as well
 

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Yesterday I got in my 2010 Chevy Cobalt after it sat for over a month. It was hot out, but my AC would only blow warm air. So first I checked the fuse and relay and both were fine. Then I checked to make sure the AC clutch was engaged and it was, so I figured it must need to be re-charged. I bought a can of AC Pro and hooked it up to the low charge port, but it showed in the green which the can said it didn't need recharging. The AC lines do not feel cold. Does this mean my compressor may be shot? How can I diagnose a bad compressor or what can I check next? Thanks.

Check the vacuum lines to the blend door, it is possible that the door is stuck or a vacuum line is off or cracked
 

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Yesterday I got in my 2010 Chevy Cobalt after it sat for over a month. It was hot out, but my AC would only blow warm air. So first I checked the fuse and relay and both were fine. Then I checked to make sure the AC clutch was engaged and it was, so I figured it must need to be re-charged. I bought a can of AC Pro and hooked it up to the low charge port, but it showed in the green which the can said it didn't need recharging. The AC lines do not feel cold. Does this mean my compressor may be shot? How can I diagnose a bad compressor or what can I check next? Thanks.
Exact same thing happened to me. Only difference was my car was parked for about 5 years. AC Pro showed it was in the green. Compressor was working.Blend door working but still blowing warm . I took it to shop. Found out it needed to be evacuated and refilled it was low on Freon . AC Pro are junk. Maybe your Freon is low. Costed $99 + tax.
 

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Discussion Starter · #8 ·
Exact same thing happened to me. Only difference was my car was parked for about 5 years. AC Pro showed it was in the green. Compressor was working.Blend door working but still blowing warm . I took it to shop. Found out it needed to be evacuated and refilled it was low on Freon . AC Pro are junk. Maybe your Freon is low. Costed $99 + tax.
Thanks. I think I will do that!
 

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I would think that if it is low enough on Freon to blow warm air that the low pressure switch wouldn’t allow the clutch to engage
 

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Its a little late, but in case none of that helped, the thermostat nornally causes that to happen to mine. Every time the thermostat failed, my ac blew hot, and thats how i knew it was bad. Its probably not that, but its happend to me a few times, so just something to consider if all else fails
 

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Please do yourself a favor and don’t use that crap! Any mechanic you take it to is going to give you shit for using AC Pro or any like products. That stuff is not the correct product to use in the ac system. You should never use any refrigerant with any type of additive or sealer unless you want future problems. In fact I will usually turn cars away when the customer has used these types of products. Many times we find the system will be contaminated by the other chemicals or additives in the products and will in turn need lots more work to get it to operate correctly again.

The correct way to test the ac system pressure is with a proper gauge set. It will connect to the suction and discharge ports, also referred to as low and high side ports. The high side is key to finding out if the system is low on refrigerant, clogged, or something else is happening. Many times if the system is otherwise in working order, the cooling fan may not be coming on. There’s a lot of things to check that you have probably not done. Although it could very well be low on refrigerant. You do not go by the low side reading to determine the charge status. Only ever use R134a in your Cobalt with no additives.

GM vehicles use a poor design on the high side port, and they often leak. This is a common place for the refrigerant to leak out. Dorman makes a valve to replace the original type with one that has a Schrader valve that is removable.
 

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One other thing a mechanic friend of mine explained to me R12 was a single gas R134 is a blended gas and the molecules are different sizes the smaller ones escape through the joints in the hoses and the system gets low stops cooling as well as it was if you just add more 134 you don’t get the same mix and it won’t cool properly got to evacuate and start from scratch dammed if I know he was trained I am not.
 
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