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Air Conditioner not cooling

 
Old 06-09-19, 04:00 PM
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chlenz62
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Default Air Conditioner not cooling

My AC suddenly stopped blowing cool air. It worked perfectly in the morning but then stopped blowing cool air when I started the car in the afternoon. I just replaced the compressor, pulled a vacuum and attempted to recharge the system. With a new 12 oz can of 134a the system charged to 65 psi on the suction side. On the liquid side the pressure is also 65 psi so I'm getting no difference in pressure across the compressor. The clutch on the brand new compressor is engaging and disengaging as was the clutch on the old compressor. It appears I have a blockage somewhere in the Freon circuit that has completely blocked flow or is the expansion valve fully open and preventing any pressure differential across the compressor? Before I start replacing all the components of the AC system, I'm hoping someone with more experience than me can point me in the right direction.
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Old 06-09-19, 05:23 PM
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So, you replaced the compressor because it stopped cooling or you just replaced the compressor because?

HVAC is common on almost all cars...
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Old 06-10-19, 05:13 AM
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If you only put in about 12 oz of R-134 your about 1/2 full then.
The one search I did came up with the SC from 2002-2004 uses 21- 23 ounces of refrigerant.
If you have the correct amount of refrigerant there are a bunch more questions.

Why did you replace the compressor?
These compressors are almost bulletproof.

Did you replace the receiver/dryer? That is not a 100% requirement (thought a good idea) unless the old compressor exploded.

How much oil is in the system?

If your refrigerant level is right and the oil level is about right then the only thing that I would consider is the TXV valve is stuck. Back in the 90's these were troublesome and I did have to replace the TXV valve on my 2006 Caravan.
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Old 06-10-19, 08:14 AM
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My AC suddenly stopped blowing cool air. It worked perfectly in the morning but then stopped blowing cool air when I started the car in the afternoon. I just replaced the compressor, pulled a vacuum and attempted to recharge the system. With a new 12 oz can of 134a the system charged to 65 psi on the suction side. The system did not empty the can of Freon. The system stabilized at 65 psi with most of the Freon still in the can. The system would not pull in the Freon and there is no differential pressure across the compressor.

I ordered a new TXV and a dryer element. My guess is that the TXV is stuck full open or has failed full open and the little bit of Freon in the system is simply being circulated around by the new compressor.

The system does maintain a vacuum and does maintain the 65 psi of pressure so there does not appear to be any leaks in the system. I saw a YouTube video of someone replacing the TXV in his GS430 so there apparently these do fail.

Hoping someone has seen these symptoms and can speak to the likely failure.
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Old 06-10-19, 10:58 AM
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Originally Posted by chlenz62 View Post
My AC suddenly stopped blowing cool air. It worked perfectly in the morning but then stopped blowing cool air when I started the car in the afternoon. I just replaced the compressor, pulled a vacuum and attempted to recharge the system. With a new 12 oz can of 134a the system charged to 65 psi on the suction side. The system did not empty the can of Freon. The system stabilized at 65 psi with most of the Freon still in the can. The system would not pull in the Freon and there is no differential pressure across the compressor.

I ordered a new TXV and a dryer element. My guess is that the TXV is stuck full open or has failed full open and the little bit of Freon in the system is simply being circulated around by the new compressor.

The system does maintain a vacuum and does maintain the 65 psi of pressure so there does not appear to be any leaks in the system. I saw a YouTube video of someone replacing the TXV in his GS430 so there apparently these do fail.

Hoping someone has seen these symptoms and can speak to the likely failure.
Do you see any bubbles in the sight glass when the compressor is running?
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Old 06-13-19, 07:06 PM
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It appears the most likely issue was the TXV. My AC is back up and running after replacing the TXV and charging the system with two 12 oz cans of 134a. The compressor was probably not the issue but I now have a new one.
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