My a/c will come on for about 2 minutes and then start blowing warm air...it will not come back on until engine has cooled down.

 

Likely is low on freon. Have it done by a pro, not worth destroying the system over charging it because most places will charge $900 to replace the compressor.

If the freon is properly serviced and you still have a problem, it is likely some washers in the compressor clutch that needs to be replaced. You can search the sticky post to read more about that.