An A/C (air conditioning) service check will test the system for leaks and make sure it has the recommended level of refrigerant. Cars used to use Freon as a refrigerant, but it’s no longer allowed to be made in the U.S., so modern cars use R-134 instead.

Most vehicles don’t need refrigerant to be added more than every few years unless there’s a leak somewhere in the system. Once your air conditioning has been topped off, your car should provide icy cold air for several seasons. If the air conditioner starts putting out warmer air again, that’s a sign of a leak, and you’ll need to have the system checked thoroughly to find and repair it.

Note: Adding more refrigerant yourself at home isn’t recommended, because there’s no way of knowing how full the air conditioning system is without the proper gauges.

If any problems are found, such as leaks, mold, or worn parts, you will be given the available options for repair or replacement. If your car’s air conditioner has mold inside, it’s usually on the evaporator core, which circulates the refrigerant through the system.