@Laotionne - The answer to your question is yes. Mechanics have detectors to determine whether your cooling system is airtight. And this is something you want to have checked sooner rather than later. There are fines for releasing refrigerants into the air in some places.
My first car was used, and one of the systems that no longer worked was the A/C. This was a bit of an inconvenience during the summer months. There were plenty of times when I was driving in city traffic during the middle of the day that I would be soaked by the time I arrived at my destination.
When I was finally able to save enough money, I took the car to a guy who worked on cars at a shop in his backyard. He wasn't a certified mechanic, but he knew everything there was to know about cars and how to repair them. However, he had no way of being certain that my A/C system was airtight after he repaired it.
He pumped the Freon into the system and the A/C worked for about a week. Then it stopped. All of the Freon had escaped. This stuff is not cheap, so I decided to just let down the windows and deal with the heat. It was less expensive that way.