Car AC not cold? Five common causes

Re-gas vs leak vs compressor — and why one fix isn't always permanent.

Air conditioning is sealed and pressurised. Over years, refrigerant slowly leaks out. A 5–10% loss per year is normal; once you’re below 60% of the original charge, it stops cooling. Five common causes:

1. Just needs a re-gas

Most common cause. €80–€120 for a re-gas with the right refrigerant (R134a on older cars, R1234yf on most cars from 2017 onwards). If the loss is gradual and the system holds pressure once recharged, it’s fine for another 2–3 years.

2. Leaking O-ring or hose

Tell-tale: a recharge holds for a week or two, then the AC fails again. Don’t keep recharging — recharging without leak repair is wasted money.

We use UV dye in the recharge to find the leak. Repair the leaking joint, then recharge. €120–€250 typical.

3. Failed compressor

Symptom: clutch on the front of the compressor doesn’t engage when AC switched on. Click on, click off — silence and warm air. Compressor failure is the bigger fix — €500–€900 typical, including replacement compressor and full system flush.

4. Blocked condenser

The condenser sits behind the front grille. Stones, leaves, road dirt block airflow over the fins. The system pressures rise, the high-pressure cut-off triggers, and the compressor switches off to protect itself.

Fix: clean the condenser fins; replace if damaged. €80–€220.

5. Cabin filter blocked

Not strictly an AC fault — but if the cabin filter is blocked, less air flows through the evaporator and into the cabin. The AC may be working but the air feels weak. Cabin filter replacement is €25–€50.

What we do

AC repair starts with a pressure check (€20, included in re-gas). If pressure holds, it’s just a recharge. If it doesn’t, we use UV dye to find the leak.

Phone 01 847 5146 — same-day AC slots usually available.