fstrfvo

I got a 01 Sable, the a/c is not cold. I got a recharge kit and put the gauge on it and it is full of freon. While the engine is running the gauge goes to almost 0 when the clutch engages then the psi goes back to normal then back to almost 0 when the clutch engages again. I s this a problem with the pressure switch??

jwko

Sounds like its low on refrigerant. Keep in mind the "normal zone" is when the compressor is running. Normal readings on high and low side with AC OFF (static pressure) depends on outside temperature, but normally is between 80-105 PSI

I would hook up your gauge with the engine off and see of you get a considerably lower reading than mentioned above. If so, I would add some refrigerant and see if it improves. If you do see those numbers you could have a blocked orifice tube.

fstrfvo

Static psi is 43, anything over 45 is considered overcharged so i think the system is full. Just wondering why the pressure bounces up and down like that or is that normal when the clutch engages?

chipset

What do you mean " static pressure. " Is that the pressure when the engine is off ? If your getting 43 lbs when the engine is off your system is empty. Your getting confused.
The pressure when the engine is off usually is around 125 - 150 lbs. on the low side when the system has a proper charge. Sometime. No offense but you might want to have it looked at by a proper service tech before you do some real damage. You cannot
put in a recharge kit without completely emptying and evacuating the system. The two
gasses are not compatable. Read the fine print on the can. It's there. Good luck.
Again no offense.

jwko

No offense Chip, but a recharge kit consist of a can of 134a, a hose with a gauge and fitting. No problem adding refrigerant with a recharge kit.

If you are seeing 40-45 psi with the engine/a/c off, you are low on charge. Start the engine, air on Max, blower on high and add refrigerant until it maintains around 30 to 35 psi with compressor running. It will continue to cycle off and on frequently until there is sufficient pressure as there is a low pressure switch to kick out the compressor.

Anything over 45 is considered overcharged with the system running.

fstrfvo

What do you mean by "the two gasses are not compatible" The recharge kit is 134a and the system takes 134a so i am not sure what is not compatible. Please explain. A/C on full and engine running gauge reads 45 psi at around 72 degrees ambient air temp, i will be renting a gauge to read the high pressure soon, what should it be?

jwko

Here's a good 2 page article.

Adding Freon to Car AC - Gauge Readings Explained | Denlors Auto Blog

I bet Chipset was thinking of a R12 to 134a retro-fit kit

chipset

that is the difference in our laws. 134A cannot be bought buy the public. There is no such thing as a 134A recharge kit here. The only thing we have is REDTAC. It is a mixture of propane and benzine. It replaces R12. Can be used on the 134A system but
that system has to be completely evacuated. Usually takes 2 cans. Only a licensed AC
tech with a CFC number can buy any kind of freon. The poster doesn't say what he has.
I'm just guessing. I just assume he is using redtac. You cannot mix that with 134A. I can only buy 134A in a 30 lb. can. $350.00 my cost. $700.00 retail. If your caught with
that stuff without a license it's a $10,000.00 fine. Then they are going to want to know
where you got it and they go after them.

fstrfvo

Here in California 134A is readily availalbe in any autoparts store, r12 is getting a little scarce though. Thanks for the article i'll read it as soon as i get a minute.