Air doesn't work

I have a 97 grand prix gt 99k. I went to turn the air on and hot air came on, about 10 minutes later the air was cool. I have the same problem in the winter hot air takes forever to come out. Thermostat never gets above 150, whats the problem.

150 degrees is too low if you have a stock thermostat. How old is your thermostat?

I've had the car 3 years, so the thermostat is at least that.

I put freeon in the air unit and 4 hours later cold air is now coming out. If there was a leak how long until the freeon leaks out and the air is hot again?

It all depends on how big the hole in the system.

Do you have the automatic climate controll system? Or manual?

Not sure, I think it's manual. Air still coming out cold!:iceslolan