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Air-conditioner works only when my Hyundai Verna is moving

The AC cooling does not improve with engine speed, I revved the engine at a standstill for a few minutes and it did nothing.

BHPian virage recently shared this with others.

I own a 2014 Fluidic Verna Petrol 1.6. I am noticing an interesting behavior with the air conditioner.

  • The AC does not blow cold air at standstill during the daytime.
  • When the car gets up to speed, the AC starts blowing cold air and stops immediately when the car stops moving.
  • When the car starts for the first time in the morning the first few minutes are cold.
  • The cooling is very good during the night and long drives.

The AC cooling does not improve with engine speed, I revved the engine at a standstill for a few minutes and it did nothing.

The engine temperature is normal and the car does not overheat.

I checked with an FNG and he is adamant that the compressor and/or evaporator needs to be replaced, without even looking at it.

I am suspecting the condenser fan has stopped working or the condenser coil is clogged up. Any ideas what may be going wrong?

Here's what BHPian CaptainBrijesh had to say on the matter:

Based on your symptoms, the condensor fan is the most probable culprit.

Start the car, turn on the AC & look into the engine bay. Condensor fan should be running. If it's not working or working slowly, you follow troubleshoot procedure like checking fuses, relays of the condensor fan and if everything is fine and fan socket is getting the current, then fan may be gone.

Here's what BHPian sagarpadaki had to say on the matter:

There are two possibilities that I can think of.

  • The refrigerant is low, ie, the AC gas.
  • Like you mentioned, the condenser is clogged.

The second case is easy to fix if you have a pressure washer. Wash the condenser through the gaps in the bumper. If you see black water dripping down, then it indicates a clogged condenser. Ensure the pressure washer jet is spread out and not pointed. If pointed it can damage the condenser. If you do not have pressure washer, take your car to any washing center and ask them to wash the radiator carefully. They will do a good job in cleaning.

Normal AC guy will be able to identify the problem.

Here's what BHPian dhanushs had to say on the matter:

All these symptoms point to the condenser not being able to dissipate heat while standstill. I'm sure the AC fan is the culprit here.

It's easy to check. When the car engine is cold (in the mornings) switch on the AC, the fan should turn on immediately.

Here's what BHPian sameerpatel90 had to say on the matter:

This is one of the common issues occuring even during normal days but it is more evident in this season only.

From my experience with repairing thousands of vehicles, following are the checks to be performed and possible solutions:

a. Perform a visual check on the AC line, condenser & compressor for any leakage (dust accumulates around the leaked line caused by the oil sedimentation). We also need to check the AC filter. This can also be a culprit. I have rectified many concerns with similar scenarios where the filter gets clogged due to dust accumulation.

b. Next step is to start the vehicle, roll down all the windows and turn the AC on (at idle) with the blower speed at 2 and temperature at minimum for 10 minutes so that the engine reaches its optimal operating temperature. Check the AC pipe in the engine compartment for moisture and temperature (the pipe must feel cold and water condensation is visible over it). Thereafter, check the same pipe near the firewall. If it is cold or feels less cool, there is a possibility of low gas volume.

c. Following the above, check for the compressor functioning. We can hear the clutch operation sound when the compressor turns on & off. If the same is not heard or you find erratic operation of frequent cut off & on, this can happen due to many reasons such as low gas volume, clogged evaporator, faulty expansion valve and last but not the least, the compressor itself.

d. To determine the gas volume, any AC technician has a two dial pressure gauge to monitor that is connected to both HP (high pressure) & LP (low pressure) lines. Additionally, it is important for us to know what type of compressor the vehicle is fitted with - whether it is a fixed / variable one (this can be known only through looking at the part number and referring to the catalogue).

e. Thereafter, a quick recovery of the gas can show us the volume of gas and oil recovered to determine the cause. Post completion of this stage, refill the gas with replacement of oil with a new one and repeat step C. Now turn off the engine, let the gauge be as it is for the next 3 hours minimum to determine any leakages. If the pressure drops, there is a leak and tracking it down may take anywhere between couple of minutes to even a day.

Another important point - AC control unit (manual / auto climate control) has different procedures in diagnosis.

My sincere apology to this forum for writing a lengthy response but, I hope this information is useful and assists in better understanding of diagnosis, no matter whether we are at FNG / A.S.S. I personally believe, it is my duty to provide basic inputs to those needing it to observe what the technician is performing on their vehicles.

Check out BHPian comments for more insights and information.

 
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