What is the capicity of an automotive ac?

If your asking how much refridgerant will it hold, each car has it's own number. And, like a tahoe, or expedition with rear air, holds twice as much. It should say on the condensor, or somewhere on the unit, or, on one of the rectangle shaped stickers under the hood. MAKE SURE you know exactely what it will hold, and remember to evacuate the system, and add that amount to the total amount. Use caution! The coolant can harm your skin upon contact, and worse yet, the whole system is under pressure. If you overpressurize it it can, and will blow up in your face, covering you with a substance that will certainly leave a mark, if you live through it all. BE CAREFUL, and pay attention to what you are doing! and remember. At its best the ac is only, knowadays, able to cool about 20 degrees cooler than ambient temp.