Noise

[EbonLinctus]

2001 Expedition XLT 5.4L V8

Near the rear wheel on the driver's side, there is a noise similar to the tone of Emergency Broadcast System that seems to sound off whenever we use the AC. It continues for a moment after turning off the vehicle.

Any idea of the cause?

 

[JUST4FUN]

do you have rear air? This is where the rear air is housed
could be the orfice tube block is going bad take it to an a/c guy
and have them conferm this

 

[EbonLinctus]

I noticed last weekend that the noise happens when not using the AC.

My wife went to see a Ford mechanic. He mentioned something about the evap system.

 

[green03]

yes the evap canistor is back there somewhere. If the solonoid under the hood fails it will pull a really hard vacuum on the fuel tank. Also when it is happening stop and see if the gas cap is the source of the noise... sometimes the cap has a small leak so it will make noise from the vacuum in the system..

Matt R