Before you service your automotive air conditioning system, you should look for the vehicle’s A/C safety sticker. Under your vehicle’s hood, you will locate a sticker which contains relevant details specific to the refrigerant requirements of your vehicle. The label indicates refrigerant type and amount as well as information about compressor lubricant. The location and design of this sticker will vary vehicle to vehicle but is generally located either on the inside of the hood or towards the front of the engine bay. (See samples below) The sticker is governed by SAE International Standard J639, which provides safety and design standards for automotive air conditioning refrigerant systems. Your label will indicate SAE J-639 compliance.
As you likely know, air conditioning systems are under extreme pressure and are capable of causing severe injury if proper guidelines are not followed. For this reason, the safety sticker includes a statement that the system should be serviced only by qualitied personnel. The additional details allow that qualified personnel to safely and efficiently work on your A/C. Failure to check the sticker could void the refrigerant recovery machine’s warranty and significantly increase the chances of using an incorrect amount of refrigerant or the wrong type or amount of oil. Details such as the proper refrigerant (R-134a or R-1234yf) or oil (PAG or POE) and whether or not the system contains dye or coolant must be known before working on your system. In addition to identifying the refrigerant, the sticker indicates the refrigerant capacity in both ounces and grams. It also states the plus (+), minus (-) tolerance range, within which the system will function properly. The labels may also contain warnings about moving parts or hot temperatures one may encounter during maintenance.
The label is required by some regulatory state and federal authorities. Avoid removing this label from your car.