Air Conditioner not cold
 

Since last summer, the air from my a/c does not get cold. To solve the problem, I just kept putting freon in the car. That would last for a few days & I would add another can.
I put a sealer in the a/c then added freon and it didn't show any leak spots yet the a/c did not remain cold.

When I add the freon, with car running & a/c on High, the fan eventually kicks on, then starts cooling the air. This only lasts for a few days.

What could be the problem, so I can get this fixed??

Thanks.

sounds like leak in system. There is a low pressure switch which will inhibit the compressor from kicking on if the system pressure is too low. When you're adding refrigerant, you're increasing the system pressure above the low pressure threshold and the compressor licks on.

So you need to find the leak.
Fluorescent dye kits are available (didn't quite understand if your sealer included such a dye).

Compressor sounds "ok" in the sense that with enough system pressure the A/C system cools, though they can leak internally.

Do not overlook the schraeder valves used to add refrigerant and check system pressure.

Find the leak fix the leak ... better yet take it to a shop that knows how to find the leak fix the leak