Has anyone ever heard of this? I have had my 2002 Lincoln LSe for about 2 months now, its freezing out and with my heater all the way up I hear a small whistle in the rear, it never whistled til about 2 days ago? Any ideas?

I have a problem where when I turn off the A/C / Heater I get a long rasberry type noise. I'm not concerned. We may need new A/C filters.

I know this is an old post, but did anyone every figure this out? I have the same thing with my 2001. It whistles the most when the blower is on high and the air selector is set so the air comes out the dash vents. If I set the air to come out elsewhere it is not as loud, but still there.

I wouldn't mind as much if it would whistle a tune I know.;)

I had this exact same problem!! It absolutely drove me nuts for the longest time! When I turned the fan on high, I could hear a whistle. But I found it...and you won't believe what it was. The vents out of the back of the console! They were closed to the point the air would whistle around them. I opened them up and voila! No more whistle. Try it!

Thanks! That's exactly what it was.

I had the same problem, drove me insane. I opened the rear vents and it was gone.

I do have a another sound when the heat is on low though. It almost sounds like the fan is wobbling. Anyone know what this is.

I can't tell you what that noise is but I can tell you the fan and motor are not to hard to get at if you want to take it out and have look.