If there is a small leak in the A/C system, it is very common for sneaky sellers to top off the freon before we arrive so that the system is working for the inspection. Once we leave, the system continues to leak out and is either not working when it arrives to you, the customer, or is not blowing as cold as it did for us. This is something that is hard to catch because a large A/C machine would be needed to diagnose the leak. This is something that is not feasible to bring to an inspection site. If you are experiencing issues with your A/C system, contact your seller.