I bought a 2003 Ford Explorer XLT on July 1, 2003. It now has 1500 miles. I have the 4.0L V6 engine.

We have started to notice that the air conditioning makes a quiet whistling sound behind the glove box. The whistle comes and goes as the air conditioning compressor cycles. We can hear the whistle for about 3 seconds befor the compressor kicks out on EVERY compressor cycle.

We don't have the fancy electronic A/C control. The A/C is good and cold...almost too cold. Cooling is not a problem.

I tried to search past postings for whistling air conditioning, but I did not find anyone with a similar problem.

Why does my air conditioning intermittently whistle as the compressor cycles? I have not taken it to a dealership for diagnosis yet.

Thanks.

 

Without further info, my guess is you are hearing the refrigerant pressures equalizing through the expansion device on the off cycle. While possibly annoying, this is not a mechanically harmful issue.

 

Thanks for the reply. I think I am familiar with the sound you may be describing. Are you referring to the hissing sound that sometimes can be heard from the A/C system, especially when you shut-off a vehicle?

The noise that I am hearing behind the dash makes a sound similar to when you to whistle very quietly. The sound is a quiet howling sound. It's loud enough to be very annoying. I have never heard this in a vehicle before.

 

Unfortunately, the only thing I can conclude is either a drive noise (belt or compressor mechanics) which is unlikely as you indicate it is more prevelant in the cabin on the passenger side; or it is refrigerant turbulance created by equalization or a restriction. It is very possible you have a restriction in your expansion device that is causing the noises on equalization. That's the best guess at this distance.

 

I had the same problem with my 2002 explorer. It ended up being the blower.

 

Ummm I have two new 2003 EB's that do the same thing. I called the dealer and the service manager said that they have had one or two other ones that made this sound because of some faulty locating of a wire. However, this is just what I was told, and I have to make an appointment for both of them and have them checked out. Also one has a strange noise that sounds like it's coming from the lock up converter. It only happens when the trans up shifts. It's not real loud, but something is not right down south in this new Explorer. I'll post what I find out.

 

My '03 also makes a whistling noise seemingly from behind the glove box area. I had also figured it was related to refrigerant flow, but if anyone finds anything else out please post...