Car AC Not Cooling? 7 Causes and Fixes (Delhi NCR Summer Guide)

Quick answer: the most common reasons a car AC stops cooling are low refrigerant from a small leak, a clogged cabin filter, a faulty condenser fan and a failing compressor clutch. Adding gas without finding the leak only works for a few days.

1. Seven Common Causes

1. Low refrigerant (gas) from a leak — cooling gets weaker over weeks. Leaks are usually at pipe joints, O-rings or the condenser.
2. Clogged cabin air filter — weak airflow and a musty smell. Very common with Delhi NCR dust.
3. Dirty or blocked condenser — the radiator-like part at the front gets packed with dust and insects and cannot release heat.
4. Condenser fan not working — the AC cools while driving fast but turns warm in traffic.
5. Compressor clutch not engaging — no cooling at all, sometimes with a click but no change in air temperature.
6. Electrical faults — a blown fuse, relay or pressure switch can stop the compressor.
7. Blend door or blower problems — air is cold on one side only, or the fan works on some speeds only.

2. Quick Checks You Can Do

• Is cold air coming out at high speed but not in traffic? Suspect the condenser fan.
• Is airflow weak on every setting? Suspect the cabin filter or blower.
• Does it smell musty? The filter and evaporator need cleaning.
• Has cooling dropped slowly over a month? Suspect a gas leak.

3. What a Proper AC Repair Includes

A good AC job starts with a pressure and leak test, then fixes the leak, then refills the exact amount of the right refrigerant (R134a in most cars, R1234yf in some newer models). It should also include cleaning the cabin filter and condenser, and checking the compressor clutch and fan.

4. How Often Should Car AC Be Serviced?

Once a year, ideally in March or April before the heat peaks, and a cabin filter clean every 10,000 km in dusty conditions.

Instant Mechanic does a doorstep car AC check from ₹499 in Gurugram, Delhi, Noida, Faridabad and Ghaziabad, with the price of any gas or parts agreed before work starts. Call +91 9266961110.