Weird A/C problem - 99 GSR

[FlatOut]

This is my first post, but I need some serious help cuz it's 100 degrees out an my A/C is out. Here's the whole story. I added some freon to my system one day and popped a leak. I saw it happen. Right at the receiver/drier. I replaced the receiver/drier, new O rings, vacuumed out the system (held vacuum for 30 mins) and recharged the system. A/C was working fantastic. 25 degree air coming out of the vents. 4 days later, no A/C. Compressor was kicking in but continually running. Continual hissing coming from the expansion valve. Mechanic recommended replacing the expansion valve. Done. Vacuumed out the system (again, held vacuum for 30-40 mins) and recharged. Was working great. 30 degree air coming from vents. 3 days later, the A/C quit blowing cold air again. Mechanic says only thing left is the compressor. It is the original (1999). When I cycle the A/C button on the console, the clutch engages and disengages as I turn it on and off. The continual hissing is back. Here's what I don't get. My A/C system was working great prior to adding the freon. Why now all these problems? Why does it work great for 3-4 days and then just stops blowing cold air? Any help would be greatly appreciated. Before I blow $3-400 on a new or rebuilt compressor, I'd try anything. Thanks in advance.

[phenom3030]

Have you diagnosed via the service manual? Maybe Too much freon was added? What's the pressure at now?
If you don't have the service manual pmme your email and I'll email it to you.

I was dealing with A/C issues as well. This 100+ degree weather is no joke. A/C is a must!

[FlatOut]

Thanks for mentioning that. We did take pressure readings after it went out this last time. When A/C is off, Low reads just under 10psi and High reads around 150psi. When we kick the A/C on, the Low jumps to about 100psi and the High drops to about 100psi. I don't know what that means. I just know that it's not right. Guy at Advance Auto that I talked to said it sounds like some blockage. I don't know. I do have the Service Manual. Thanks for the offer.

[djboi209]

Are you sure you were not leaking? If it was working for 3-4 days and it stops maybe you have a leak somewhere. From what i have gather from reading forums same pressure on both high side n low side means you have a bad ac compressor

[Blazinqwickly]

This almost sounds like when you added too much freon you blew a seal some where and it's small enough that your recharge last a few days then it's gone as you state. It's just a guess tho so take it for what it's worth. GL

[FlatOut]

Thanks for suggestions. I thought about a leak too, but wouldn't that show up when the system was under vacuum purge for 30-40 minutes and the pressure not moving?

[stillhere153]

leak somewhere, I had similar issue with low pressure hose

[MasterP_Nice]

Originally Posted by FlatOut

Thanks for mentioning that. We did take pressure readings after it went out this last time. When A/C is off, Low reads just under 10psi and High reads around 150psi. When we kick the A/C on, the Low jumps to about 100psi and the High drops to about 100psi. I don't know what that means. I just know that it's not right.

????? That's actually completely backwards. When the A/C is turned off, the entire loop moves to equilibrium. The pressure on the high and low sides should be equal.

When you turn the A/C on, the compressor starts working and you'll see the high side go up, and the low side go down.

If you're 100% absolutely sure that setup is correct, then you should be feeling cold air with the fan turned on but the A/C switch OFF, and normal air with the A/C switch ON.

Have you checked the A/C diode to see if it's working correctly?

[jdmjim]

sounds like the expansion valve took a dump, just cause its new dosent mean a thing anymore.. usually with compressor failure, it cant build any pressure. you need to use a leak detector and dye to find leaks, dont trusy the vacum method, not reliable.

[FlatOut]

Originally Posted by MasterP_Nice

????? That's actually completely backwards. When the A/C is turned off, the entire loop moves to equilibrium. The pressure on the high and low sides should be equal.

When you turn the A/C on, the compressor starts working and you'll see the high side go up, and the low side go down.

If you're 100% absolutely sure that setup is correct, then you should be feeling cold air with the fan turned on but the A/C switch OFF, and normal air with the A/C switch ON.

Have you checked the A/C diode to see if it's working correctly?

You're right. The opposite is correct. Sorry. Was going by memory. Bad memory it appears.

How do you check to see if the A/C diode is working correctly? Is that something I can do myself? Do you need a special tool or meter?

[optimalbeing]

Automotive Air Conditioning Leak Repair - YouTube

[stillhere153]

^ great friggin vid

[FlatOut]

Originally Posted by optimalbeing

Automotive Air Conditioning Leak Repair - YouTube

If I do have a leak and the system is low on refrigerant, the compressor won't kick in right, even though the clutch is engaging. But what if I add a can of refrigerant? It should be enough for the compressor to kick in and I should feel cool air. If that works, then I know I've got a good compressor, just need to find the leak. Is that correct thinking? Thanks for all your posts. I watched that Scotty Kilmer video. That guy cracks me up. He knows his stuff though.

[MasterP_Nice]

You can test the A/C diode with a DMM that can test for continuity. The Helms manual tells you what points to test on the diode.

Originally Posted by FlatOut

If I do have a leak and the system is low on refrigerant, the compressor won't kick in right, even though the clutch is engaging. But what if I add a can of refrigerant? It should be enough for the compressor to kick in and I should feel cool air. If that works, then I know I've got a good compressor, just need to find the leak. Is that correct thinking? Thanks for all your posts. I watched that Scotty Kilmer video. That guy cracks me up. He knows his stuff though.

The compressor will stop working if the pressure in the loop gets too low. That's done as a safety mechanism so the compressor isn't trying to compress air or vacuum.

If you add refrigerant, the pressure interlock is satisfied and the compressor will kick in. Make sure you measure the low and high pressure readings, along with the ambient temperature.