AC question. Clutch, I think.

[HCPcustompaint]

Hi all,
Important info first, I have a 1990 K1500 Silverado, 4wd, manual trans, 5.7 tbi. The previous owner put in a cam when he had the engine rebuilt, but otherwise pretty much stock so far.

The issue is- when I turn on my AC, the AC compressor doesn't stay engaged. You can hear it "click" on, it the pulley will engage for a couple seconds, then it disengages again. Then just repeats.

My thoughts are either the compressor clutch has gone bad, or one of the AC electrical components is going bad and sending an on/off/on/off signal.
I have the "fancy" digital climate controls, if that makes any difference.

Has anyone run into this? Know what the problem is? Want to guess? lol

I first noticed this about 3 weeks ago. Before that, the AC worked great and blew cold. It murdered my gas mileage, but it worked.

 

[BIG_KID]

Probably low on charge and kicking out on low suction pressure

 

[Colonel Sanders]

Probably low on charge and kicking out on low suction pressure

Yep. Try hooking up a pressure gauge, I did that on mine and you could see the compressor turned off when the pressure dropped below a certain threshold. You may have a leak losing refrigerant somewhere, might want to get the system checked.

 

[HCPcustompaint]

Thanks. I'll check the pressure and see where it's at. Hopefully I can find an obvious and easily replaceable, cheap, leaking part and avoid having to take it in. Lol.

 

[BIG_KID]

Mine leaks at the compressor. The big o-rings are bad.

 

[hfrederick36]

Any luck? My 98 is doing the same thing. Checked the pressure and it's good. Replaced the low pressure switch and still doing it. Any other ideas? Thanks

 

[hfrederick36]

Hi all, I'm new so if there is a thread please point me in that direction, as I've searched and cannot find anything.
Okay so I have a 98 ecsb 5.7 silverado and the compressor kicks on and off. I've tried adding the can from Napa to it and it didn't help, I don't want to over charge it. I have tried a new low pressure switch and also jumping the low pressure switch. Still just kicks on and off. Nothing seems to work. Could it be the ac clutch? I don't want to buy one if there is nothing wrong with mine. Any help would be much appreciated. Thank you

 

[chipskittles]

Low pressure switches are hit or miss. I had a parts store switch that NEVER shut off the compressor. Evaporator would freeze up on long trips. Spent the extra few dollars on a delco part and it's better now. AC Delco part is the way to go in this case.

 

[hfrederick36]

Low pressure switches are hit or miss. I had a parts store switch that NEVER shut off the compressor. Evaporator would freeze up on long trips. Spent the extra few dollars on a delco part and it's better now. AC Delco part is the way to go in this case.

Okay thank you I'll order one and try it