AC questions

[masapell]

I have a 1996 Cherokee Sport 4.0. The AC has not been cooling well at well, so I bought a can of EZ Chill from the local auto store. I connected the gauge as instructed and followed all instructions. The pressure was at about 37.5 at an ambient temp of 102, yeah that hot. I added an entire can (18oz with oil and sealer). The pressure really did not change at all. The air was cooling considerably better. My question is that the compressor is humming louder at about 2000 rpms and the pressure on the gauge drops to around 25psi or a little lower. I looked at the sight glass and there are bubbles in it. Do I need more refrigerant or is there another problem?

Sincerely,
Matt

[fredjacksonsan]

First of all there's probably a leak in the system. You can buy dye that will show where that is.

Every time I've refilled a system, I kept adding coolant, and always needed more than one can. The refigerant acts as the lubrication for the system, so if you're low then the compressor isn't getting lubricated as well as it should. I'd try adding another can or two....and the pressure might fluctuate somewhat, as the compressor cycles.