A/C system leak

1999 CHEVROLET SUBURBAN
202,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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JNARON_NGC
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A/C suddenly stopped blowing cold. (Note: all A/C system installed new 3 years ago) Put 24 oz of 134A in using gauged apparatus. Showed 150 psi high side, 25 psi low side. Checked for leaks using black light flashlight, none seen.Began drive to town to replace used 134A. Noticed A/C blowing hot immediately. Upon return to shop checked pressures. No pressure shown, and low pressure switch had compressor clutch disengaged. Went back to town and bought 134a with leak stop. Put almost all of the 22 oz can in, when green zone was acquired, we noticed that every time we functioned the pull trigger the pressure was decreasing.
Rear A/C was not involved in replacement of A/C components 3 years ago.

So I am presuming that is where this very large leak is.
Jul 12, 2020 at 7:16 AM
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ASEMASTER6371
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Good morning,

Stop leak was a very bad idea. That stuff causes more issues than it tries to solve. The expansion vale is what fails almost immediately after installing this sealer.

As far as the leak, you can rent a UV kit to look for the leak or use a bright LED light. The light is bright enough to show the leak.

https://www.2carpros.com/articles/air-conditioner-leak-detection

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

The refrigerant amount is on the chart I attached,

I would flush the system and try to get all that sealer out.

Roy
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Jul 12, 2020 at 7:45 AM
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JNARON_NGC
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Well, hopefully the severity of the leak evacuated everything including the stop leak immediately.

We used a UV light as stated above, and saw no residue form leaking gas.

Looking at your chart 3 12 oz cans of 134a did not come close to filling the system. Although pressure on high side did show 120 psi.
Jul 12, 2020 at 8:46 AM
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ASEMASTER6371
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Okay, 120 is low considering it is summer time.

The Freon went somewhere. I would check or consider the front or rear Evaporator core as a possibility. I attached a YouTube video of the replacement for you.

https://www.youtube.com/watch?v=FBhnvJf_Dl0

The evacuation does not remove the sealer, flushing it removes the sealant.

Roy
Jul 12, 2020 at 2:00 PM
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JNARON_NGC
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What do you consider a reasonable pressure for summer?

I have ordered blank off plugs for rear A/C.
Jul 14, 2020 at 5:29 AM
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ASEMASTER6371
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A normal high side is 2 times ambient temperature plus 15%.

The low side should be 25-30 pounds rock solid.

Roy
Jul 14, 2020 at 5:35 AM