The system holds 2.2 lbs or 35.2 ounces. Me personally on a older car if it blows warm, I let all the freon out then go to the store and put in the appropriate amount. In your case let it out and put in just about 3 cans (12 oz each). Were I live they are $6 bucks a can for 134a. I know people here are dead against this but it never failed me yet.