1985 190e Air Con problem
 

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.

check to make sure that the aux fan(s) are coming on low stage. When the car is idling in hot weather with the A/C on it shouldn't take too long for the refridgerant pressure/temperature (not sure what the sensor on the 190 is) to turn the low stage fans on. This will blow air through the condensor allowing the refidgerant to do its job better.

Not sure what you mean with "aux fan(s) are coming on low stage". Do you mean to say that aux fans should also start running in addition to the main fan? Or do you mean that the aux fans should run on slower speed?

According the to the technician, the fans are working fine. I can hear and see the fans working in full force since the ambient temperature here is around 45 degrees C. However, they are not coming on low speed nowadays. Low fan speed happens during the months of Dec-Feb when the temperature is better, i.e. around 20 degrees C.

Will it give a problem if the fans are on high speed when the engine is idling?

chk the main cooling fan clutch. if you have the 2.6, the fan clutch may be getting weak which doesn't pull much air through the condensor at idle.