Atalbot20

As the title states, my 06 Honda Accord with 176k on the dash has had air conditioning issues for probably the last 2 years. Basically, the air conditioner works sporadically when it is set--it blows nice and cold for about 3-5 minutes, and then kicks out, blowing warm outside air. More often than not, the a/c doesn't blow cold. While it is blowing warm air, the dashboard still shows that the A/C is on, and temperature/fan changes don't affect how often the system starts to function. I took it to my go-to mechanic, who doesn't have much experience with a/c systems, and he couldn't figure out the issue. Any ideas what could be causing this?