Air conditioning

[avmx]

1997 XJ sport 149,000 mi.

I know it's not the season for a/c but...

has any one had any problems with the a/c where it works fine for about an hour of continuous use, then all of a sudden it feels like the cold air is being blown overboard instead of into the passenger compartment, yet you can still feel some cold air coming in. Once I shut down the jeep wait 30 minutes, start the engine, and turn the a/c back on, the a/c works fine...for another hour.