How many grams of refrigerant should be added to a car's air conditioning system?
2 Answers
Depending on the vehicle model, the required amount of refrigerant varies, typically ranging from 300 grams to 600 grams. Methods to determine whether refrigerant needs to be added: Insufficient refrigerant: When the air conditioning system is operating normally and continuously, bubbles appear in the sight glass of the car's air conditioning pipeline, indicating insufficient refrigerant (Freon) and the need for a recharge. Excessive refrigerant: When the air conditioning system is operating normally and continuously, no bubbles appear in the sight glass of the car's air conditioning pipeline. Additionally, when the air conditioning is turned off, no short-term bubbles appear, indicating an excessive amount of refrigerant (Freon) that needs to be discharged. Normal refrigerant level: When the air conditioning system is operating normally and continuously, no bubbles appear in the sight glass of the car's air conditioning pipeline. However, when the air conditioning is turned off, a short bubble appears, indicating a normal amount of refrigerant (Freon).
When I first drove the car, the air conditioning wasn’t cooling properly. After a check at the repair shop, my car was topped up with about 650 grams of R134a refrigerant. The mechanic said the amount varies by model—generally, small cars start from 500 grams, while compact or sedan models need 600-800 grams; SUVs or pickup trucks require more, around 800-1100 grams. The engine hood label specifies the capacity—mine, a 2018 model, indicates 700 grams. Before adding refrigerant, the system pressure must be checked: normal low pressure is 30-45 psi, and high pressure is 250-350 psi. Overfilling can overpressurize and damage the compressor, while underfilling weakens cooling. DIY is not recommended—have a professional shop check for leaks to avoid wasting money and downtime. I now schedule regular spring AC maintenance to prevent surprises.
