a/c warm on passenger side

[longbaugh]

Hi, all. A few weeks ago I bought this 2002 v70xc. It has about 104K miles. I've been noticing that while the driver's side a/c stays pretty cool, the passenger's side doesn't stay cool after several minutes of operation. I put a thermometer in the vents, and while on max cool, the driver's side will stay down around 64 deg F, but the passenger side will be around 80 deg F on a 95 deg day.

I bought one of those cheap low-side gauge/fill valves to put in a can of refrigerant, and found that the low-side pressure is fluctuating between 30 and 60 psi or so. I hear a device turning on with a click (I assume this is the compressor) and noted the low-side pressure drops. After ten or twenty seconds, the pressure gets down to about 30 psi and the compressor turns off and the pressure rises back up to about 60 psi.

It cycles like this several times per minute.

I added the refrigerant (a small 12-oz can) and the a/c is now cool on passenger's side, but the compressor is still cycling. The pressure is behaving the same way, fluctuating between 30 and 60 psi with the cycling of the compressor.

My question is, why is the compressor still cycling? Am I low on oil? If I'm still low on refrigerant, should I add some oil, too?

Sorry for the long post. Any help is appreciated. Thank you in advance.

[FCPEURO]

If the driver side is staying nice and cool, then it is not a freon issue. More then likely, the door that opens to allow air from the AC evaporator is not opening on the passenger side.

[longbaugh]

For the first several minutes of operation, the passenger side is cool. Then, after several minutes, the passenger side warms. Would that still indicate an air flow problem?

Also, why is my compressor cycling so much?