'98 Nissan Altima - AC gradually gets warm

[nwatts]

'98 Nissan Altima. 200,000 miles. Runs great. However, I can't figure out the problem with the AC. Here's the problem: AC blows ice cold for a few minutes then begins gradually getting warm, finally getting downright hot. For whatever reason, if i turn the AC off for a few minutes it, more often than not, begins blowing cold again when I turn it back on. (This works almost all the time - but not every time.) Oddly, the AC seems to remain cold on cooler days and in the shade. (Again, their are exceptions to this rule). Also, the AC seems to always work perfectly when I first start the car after it's been sitting for a while. Very peculiar. Took it to a shop. Was told the compressor is good. They told me they thought they discovered the problem by replacing the thermostat. Apparently, that wasn't the problem. I can't tell if it's a diaphragm issue or an issue with the compressor having trouble kicking on. I've checked the "blend door actuator" and that "seems" to be working fine - although I haven't replaced it. Any suggestions? Thanks, nick

[Jsmitty]

To me this is screaming a radiator/electric fan/clutch issue. The high side pressures could be getting way up there, and kicking off the compressor. Even with it running, the cooling will be terrible without the heat removal of the condenser. High and low pressures will start climbing without airflow.

If the cooling gets nice once moving, then I'd be looking at some type of fan problem, or airflow problem (debris between radiator & condenser).

[Dougflas]

Things to check are clutch gap and to see if it is freezing up.

[atikovi]

Moisture in the system can freeze, cause a blockage, then melt after a few minutes and start working again.