Why is my car's AC not blowing cold air?
Warm air from a car's AC is most often low refrigerant from a small leak, a failed compressor or clutch, or a condenser blocked with debris. A recharge alone ($150–$300) fixes it only if the leak is found — refrigerant doesn't get 'used up', so a system that's low has a leak somewhere.
Likely causes
- Refrigerant leak — The most common cause. Hoses, seals, and the condenser leak slowly with age.
- Compressor or clutch failure — No click from under the hood when the AC switches on, or grinding when it engages.
- Blocked condenser — Bugs and road debris choke airflow through the fins at the front of the car.
- Electrical fault — A blown fuse, failed relay, or bad pressure switch can stop the system cold — cheap parts, real diagnosis needed.
What you can check yourself
- Check that the condenser fan runs when the AC is on (look through the grille with the engine running and AC on max).
- Feel the AC lines under the hood: if one is ice cold but the air is warm, the problem may be a blend door, not the AC itself.
- Skip DIY recharge cans if the system is empty — adding refrigerant without finding the leak wastes the can and can overcharge the system.
Typical cost
Typical in San Francisco, CA: diagnostic + recharge $150–$300; leak repair $300–$800 depending on the part; compressor replacement $800–$1,600.
When to call a pro
Grinding or screeching when the AC engages, or a system that blows cold for a week after every recharge — that's a leak or compressor job, not another can of refrigerant.
Get free quotes from San Francisco, CA pros →
Data by Servik — verified local pros from official license records and public sources. Cost figures are typical ranges, not quotes; a pro's written estimate is the real number.