Yes, sealers do work. I used a sealer on a 1998 Mazda 626 and the ac has been fine for the last 3 years. The sealers only work though if the leaks are tiny.
Vacuum leak
If the air conditioner is on but not cooling the house properly, you may have a leak in your duct work. A leak would allow all of the cold air to escape, blowing into the outdoors instead of cooling your house.
disconnect the battery for 45 seconds . That will reset the system and allow the AUTO to light up and receive new gas. Once the refrigerant level is correct, that particular light should turn off, and the a/c system should begin to work properly. If not, you can always use a scanner from Autozone, Dicount, or O'Reilly's Auto parts to try to fix it. Hope that helps! Avoid system sealers and leak stop. These products are band-aids, not repairs. Leak sealers react with air. If there is air in the system, the leak stop will congeal into a thick green jelly. www.acpartshouse.com
New seals work best.
There are sealers available, but not to the general public. And they only work on very small leaks. Most cities and states require a license in order to purchase hvac materials such as Freon (R-22, R-404, etc.). The one exception is the coolant for automobiles. But this is not used in home ac units. If you have a leak, contact a licensed hvac contractor to have it repaired. They will usually warranty the repair. Depending on your area, it shouldn't cost more than $150
Most common problem is a leak in the system is present.
NO! its like looking for a magic pill to make you younger or live longer. Do not use it you will clog up the entire system and wind up replacing it. Find the leak and properly repair it. YES IT WILL STOP THE LEAK BUT NEEDS TO BE REPAIRED ASAP IT IS NOT WISE TO US IT BUT IT WIL STOP A SMALL LEAK.
Start with: Possible control, blend door or blend door actuator, low pressure switch, leak in system.
At best, they're a temporary stopgap measure until you can get the gasket replaced.
I've had very good luck using power steering sealers especially on Ford products. If the hose or steering rack is not pouring out fluid, you may have good luck with it.
If she got an industrial vacuum sealer then she is in good shape. The vacuum sealers used by professional are usually of very good quality. It's the one that are promoted on informercials that are usually the problem.
You can buy a charge kit from your local auto parts store and follow directions but if it needs a charge it must have a leak. Have the leak repaired first. This is best done by a garage that does AC work.