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AC not blowing as cold anymore, has full charge

camosilver on Tue May 05, 2009 11:57 AM User is offline

Year: 1996
Make: saturn
Model: sc2
Engine Size: 1.9L
Refrigerant Type: 134
Ambient Temp: 85
Pressure Low: 38
Pressure High: 125
Country of Origin: United States

My 96 saturn sc2 isn't blowing ice cold ac anymore, a few weeks ago it seemed ok but not anymore. it's kinda cold, but not enough to really do it's job (i live in florida). the compressor kicks on, it has a full charge and is NOT leaking (has held this charge for over 1 year and has not lost any pressure), low side is reading 38 psi and high side is at 125, ambient temp is about 85. shouldn't the high pressure be reading closer to 200 PSI?

what could be the problem here?

GM Tech on Tue May 05, 2009 12:13 PM User is offline

Quote
[ it has a full charge and is NOT leaking (has held this charge for over 1 year and has not lost any pressure),

You can't typically determine charge level by pressures-lots of variables- best to do it by weight of refrigerant- so reclaim, weigh, and recharge- see if system comes back to life. Or at least add some refrigerant and see what happens.

The static pressure does not change with the amount of refrigerant-- 4 ounces and 4 pounds will register the same static pressure in your car..

You say it is NOT leaking- yet that is the biggest failure mode of any mobile a/c system-- better to rethink your analysis...

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

camosilver on Tue May 05, 2009 12:37 PM User is offline

well, when i charged it last year after replacing a line, it had 38 psi on the low side. now, 1 year later, it still has 38 psi. i would think that indicates that the system is not leaking. i didn't add anymore refrigerant because i didn't want to overcharge the system.... every saturn i have ever recharged blew cold at 35-40 psi on the low side.

assume it has the proper amount of refrigerant... what would cause the high side to read that low?


Edited: Tue May 05, 2009 at 1:30 PM by camosilver

GM Tech on Tue May 05, 2009 1:28 PM User is offline

I just checked a 2006 Caddy today- it had 35 psi on low side-and 70 psi high side-- pulled refrigerant out- it had only 0.20 lb of 134a in it..I then recharged to 1.43 lb as specified and it cools like a champ- at 36 psi low and 250 psi high... now to find that dastardly leak...

So proof that pressures don't tell the whole story- your high side is too low-- most likely is low on refrigerant-

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Cussboy on Tue May 05, 2009 2:27 PM User is offline

Quote
Originally posted by: camosilver
My 96 saturn sc2 isn't blowing ice cold ac anymore, a few weeks ago it seemed ok but not anymore. it's kinda cold, but not enough to really do it's job (i live in florida). the compressor kicks on, it has a full charge and is NOT leaking (has held this charge for over 1 year and has not lost any pressure), low side is reading 38 psi and high side is at 125, ambient temp is about 85. shouldn't the high pressure be reading closer to 200 PSI?
what could be the problem here?


I think GM Tech already replied, but 125 psi on high side means low charge of refrigerant, like you have a leak. Static pressure or low side pressure won't typically indicate a leak unless it's really low. Listen to GM Tech.



Chick on Tue May 05, 2009 7:04 PM User is offlineView users profile

add some refrigerant, bring the high side up to around 190 to 195 at 85 degrees, and you'll see that GM tech is right on the money. Low charge is indicated

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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