A/C turns warm after a few minutes... why?
 

Well, I have a 1995 Nissan Pathfinder XE 6 cylinder manual transmission with 156k miles on it. I've owned it for a little under a year now, and for as long as I've had it the A/C will run for about 10 minutes pretty well, but will then start blowing warm air. It runs nice and cold when it is cold, so I doubt it needs to be recharged, but then again I don't know a whole lot about A/C. Also, when the air turns warm, I usually turn the A/C off for about 20 minutes, and then turn it back on, and it usually runs cold again for a few minutes.

I know engines pretty well, but not A/C. I do all my own work on my cars, but never A/C; I usually just take it to a mechanic. I'll probably take this to a mechanic as well, but I want to go there with some ideas of what the problem may be.

I appreciate any info yall have. Thanks.

During this time that it is blowing warm air, is the compressor clutch on?

Sounds like probably a leak somewhere, but only under pressure. Would be a very small leak, IF that's the case. When it is cold, is it really cold?

No, when the air turns warm, the compressor clutch is off.

I checked the pressure of the system today, and it is at 45 psi, which is its recommended level. I've never recharged it or anything while I've had the truck, and the a/c is always really cold, so that kinda tells me it's probably not a leak.

Maybe it's some kind of switch that shuts the compressor clutch off when it gets too hot? That's all I can think of, but I don't know much about a/c.

There is a switch in the suction line (the larger of the two lines on the compressor that gets cold when things work) that kills the clutch when there is low gas. Give that a check.

Hmm, I'll check it out. Thanks.

Yeah, if that's the case, I would bet on a pressure switch.