My Mercedes 190e 1985 model car airconditioner stops cooling when the car is idle. However, when I rev up the engine, cool air starts coming again. The cooling is fine when the car is moving.

The mechanics have already changed the gas tank, filter, expansion valve, evaporator, condenser and compressor. The refrigerant type is R12.

When the car is inside the workshop, the airflow temperature reading is 16 degrees C. When I take the car outside the shop, the air temperature shoots up till 24 degrees C. When I rev up the engine to 2000 rpm, I can achieve 13 degrees C even outside the shop.

I am in Dubai and the temperature here now ranges between 40 to 50 degrees C.