I took my car to a shop to have the A/C evac done and charged. When they were done the mechanic tells me NOT to use my A/C anymore unless I get my electric fans to turn on when I run the A/C.

I have had my fans setup with an adjustable switch that turns them on at 185 engine temp, they do not turn on till that temp, even if I run the A/C.

I asked the guy to explain why the fans HAD to be on when I run the A/C and he said I need them on to keep the compressor from burning up. I think he is full of BS because he could or would not explain how this would happen.

My motor temp is fine, the fans come on when the motor is warm enough and I dont want to rewire the thing to turn fans on when the A/C is on unless its needed.

Is there any advantage to running the fans at low engine temps?

 

IIRC, both the single and dual fan set-ups were designed to come on with temperature and/or AC--this latter would turn on regardless of engine temp.

JamesC

 

The fans are required to maintain airflow across the condenser coil (in front of the radiator) to enable heat transfer from the refrigerant when running the A/C. Without this heat transfer your A/C will not operate correctly, and could slug your compressor (bad for it). While you're moving there should be enough air crossing the coils for it not to be a problem. When stopped in traffic w/no airflow, if you have the A/C on, you'll probably notice that it stops putting out cold air. This is from the lack of heat transfer up front. Just shut it down then or turn on your fans.

 

Thanks,
that makes some sense.
Now why didnt he tell me that in the first place?

 

Most auto mechanics are not hvac technicians. They can swap parts, vacuum and charge but may be only relaying what they've been told not to do without understanding why.

To be a little more specific: Without heat transfer your system will continue to build pressures placing more drag on the compressor and engine. This could result in wear on the compressor and possibly result in a broken belt or, in the extreme case, blowing the high pressure blowoff and losing your charge.

In an electric driven compressor system (your home unit perhaps) this higher pressure can burn out the compressor motor windings requiring a replacement compressor.