A/C Mystery - 11 Burb

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rmaker

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In June, I noticed the a/c was cold-ish, but not really cold, and it seems it would kind of alternate between cold and ambient temp air.
I attempted to add some freon with an over-the-counter can. While filling, I may have added some while the compressor was not on. Overall I really didn't add too much (a few small bursts) and I quickly abandoned the procedure.

Took it to a mechanic, I let him know what I did and assumed it probably just needed a proper fill with gauges etc. He told me the accumulator was bad, the orifice was dirty and it was low - changed out both, vacuumed, and refilled.

The a/c blew colder than a sob after the fix, and was working fine till last weekend.

Last weekend while driving to Orlando, on the way up you could see the air coming out of the vents - misty/fog. It remained cold, but after a couple of hours, it was clearly not blowing very cold air anymore, and no more misty/fog. Parked it for a few hours to unload my daughter's stuff at her dorm. The ride home was borderline uncomfortable.

The a/c never got super cold, if you put your hand right up to the vent it felt cold, but not cold enough to really cool the vehicle down. I ran the rear a/c for a few minutes and it felt almost warm.

Took it back to the mechanic yesterday, he spent 3 hours on it - checked the orifice again and it was clean (he replaced it again), the compressor works fine, and the fans are blowing fine, it was a little low on the pressure. He used a sniffer tool to check for leaks and couldn't find any. He pulled out all the gas and refilled it again. Says it's blowing 47 out the vent now.

He said my pressure is 40 on the low side and 200 - 220 on the high side. I just saw a similar post where @Geotrash posted a table of R134A pressure per outside ambient temp. According to that table, it seems that my pressure should be higher - it's in the 90's here every day.

No charge for the service - and he will be handing me off to his a/c guy (a/c shop exclusively) if it should start acting up again.

Any thoughts?
 

Geotrash

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In June, I noticed the a/c was cold-ish, but not really cold, and it seems it would kind of alternate between cold and ambient temp air.
I attempted to add some freon with an over-the-counter can. While filling, I may have added some while the compressor was not on. Overall I really didn't add too much (a few small bursts) and I quickly abandoned the procedure.

Took it to a mechanic, I let him know what I did and assumed it probably just needed a proper fill with gauges etc. He told me the accumulator was bad, the orifice was dirty and it was low - changed out both, vacuumed, and refilled.

The a/c blew colder than a sob after the fix, and was working fine till last weekend.

Last weekend while driving to Orlando, on the way up you could see the air coming out of the vents - misty/fog. It remained cold, but after a couple of hours, it was clearly not blowing very cold air anymore, and no more misty/fog. Parked it for a few hours to unload my daughter's stuff at her dorm. The ride home was borderline uncomfortable.

The a/c never got super cold, if you put your hand right up to the vent it felt cold, but not cold enough to really cool the vehicle down. I ran the rear a/c for a few minutes and it felt almost warm.

Took it back to the mechanic yesterday, he spent 3 hours on it - checked the orifice again and it was clean (he replaced it again), the compressor works fine, and the fans are blowing fine, it was a little low on the pressure. He used a sniffer tool to check for leaks and couldn't find any. He pulled out all the gas and refilled it again. Says it's blowing 47 out the vent now.

He said my pressure is 40 on the low side and 200 - 220 on the high side. I just saw a similar post where @Geotrash posted a table of R134A pressure per outside ambient temp. According to that table, it seems that my pressure should be higher - it's in the 90's here every day.

No charge for the service - and he will be handing me off to his a/c guy (a/c shop exclusively) if it should start acting up again.

Any thoughts?
Sounds like the classic symptoms of a leaking Schrader valve at one of the two service ports: a long, slow decline of performance over a period of days to weeks. I would take a little soapy water to the service ports with the dust caps off and 10 bucks says you'll see bubbles.
 

j91z28d1

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that gm high side port for sure. I went thru 2 oem from rock auto before one sealed pretty well. still don't believe it's 100% as the sniffer doesn't hit the the cap on but crack it loose and it will for a sec

nice that he checked it without charge
 

BG1988

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In June, I noticed the a/c was cold-ish, but not really cold, and it seems it would kind of alternate between cold and ambient temp air.
I attempted to add some freon with an over-the-counter can. While filling, I may have added some while the compressor was not on. Overall I really didn't add too much (a few small bursts) and I quickly abandoned the procedure.

Took it to a mechanic, I let him know what I did and assumed it probably just needed a proper fill with gauges etc. He told me the accumulator was bad, the orifice was dirty and it was low - changed out both, vacuumed, and refilled.

The a/c blew colder than a sob after the fix, and was working fine till last weekend.

Last weekend while driving to Orlando, on the way up you could see the air coming out of the vents - misty/fog. It remained cold, but after a couple of hours, it was clearly not blowing very cold air anymore, and no more misty/fog. Parked it for a few hours to unload my daughter's stuff at her dorm. The ride home was borderline uncomfortable.

The a/c never got super cold, if you put your hand right up to the vent it felt cold, but not cold enough to really cool the vehicle down. I ran the rear a/c for a few minutes and it felt almost warm.

Took it back to the mechanic yesterday, he spent 3 hours on it - checked the orifice again and it was clean (he replaced it again), the compressor works fine, and the fans are blowing fine, it was a little low on the pressure. He used a sniffer tool to check for leaks and couldn't find any. He pulled out all the gas and refilled it again. Says it's blowing 47 out the vent now.

He said my pressure is 40 on the low side and 200 - 220 on the high side. I just saw a similar post where @Geotrash posted a table of R134A pressure per outside ambient temp. According to that table, it seems that my pressure should be higher - it's in the 90's here every day.

No charge for the service - and he will be handing me off to his a/c guy (a/c shop exclusively) if it should start acting up again.

Any thoughts?
did you clean the evaporator coil? and a/c filter mod?
 

ivin74

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In June, I noticed the a/c was cold-ish, but not really cold, and it seems it would kind of alternate between cold and ambient temp air.
I attempted to add some freon with an over-the-counter can. While filling, I may have added some while the compressor was not on. Overall I really didn't add too much (a few small bursts) and I quickly abandoned the procedure.

Took it to a mechanic, I let him know what I did and assumed it probably just needed a proper fill with gauges etc. He told me the accumulator was bad, the orifice was dirty and it was low - changed out both, vacuumed, and refilled.

The a/c blew colder than a sob after the fix, and was working fine till last weekend.

Last weekend while driving to Orlando, on the way up you could see the air coming out of the vents - misty/fog. It remained cold, but after a couple of hours, it was clearly not blowing very cold air anymore, and no more misty/fog. Parked it for a few hours to unload my daughter's stuff at her dorm. The ride home was borderline uncomfortable.

The a/c never got super cold, if you put your hand right up to the vent it felt cold, but not cold enough to really cool the vehicle down. I ran the rear a/c for a few minutes and it felt almost warm.

Took it back to the mechanic yesterday, he spent 3 hours on it - checked the orifice again and it was clean (he replaced it again), the compressor works fine, and the fans are blowing fine, it was a little low on the pressure. He used a sniffer tool to check for leaks and couldn't find any. He pulled out all the gas and refilled it again. Says it's blowing 47 out the vent now.

He said my pressure is 40 on the low side and 200 - 220 on the high side. I just saw a similar post where @Geotrash posted a table of R134A pressure per outside ambient temp. According to that table, it seems that my pressure should be higher - it's in the 90's here every day.

No charge for the service - and he will be handing me off to his a/c guy (a/c shop exclusively) if it should start acting up again.

Any thoughts?
Have you checked the high pressure and low pressure sensors? Once they go bad the AC does exactly what you are experiencing. Buy AC Delco parts, like $40 bucks on Amazon.

Replace them and report back

 

Geotrash

Dave
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Have you checked the high pressure and low pressure sensors? Once they go bad the AC does exactly what you are experiencing. Buy AC Delco parts, like $40 bucks on Amazon.

Replace them and report back

Yes, this is also an excellent possibility.
 
OP
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rmaker

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Have you checked the high pressure and low pressure sensors? Once they go bad the AC does exactly what you are experiencing. Buy AC Delco parts, like $40 bucks on Amazon.

Replace them and report back

I will look into this, thanks. Haven't driven the vehicle much since last week.
 

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