Please help end the noise!

[treats54]

2004 Explorer

After replacing the blend door and motor, I was surprised to hear an awful noise coming from the engine after starting . There is a high pitched chirping coming from the air box, right over the engine. It sounds similar to an alternator belt slipping, but this does not diminish with driving or engine temp. There is a door piece behind the glove box that is also broken- it attaches to a vacuum motor(Repairing this as well). I have not felt any heat come into the front of the car since replacing the blend door. Uncertain if related or not.
Open to ideas. I would rather drive a quiet cold car than a warm obnoxious one.

 

[pet575]

Are you sure these two things are related? If that noise is really coming from the location you describe it could be a pulley bearing going bad at the same time and it is just coincidence.

 

[treats54]

No, I am not sure they are related. In listening more, it sounds like it might be coming from the belt area, but applied belt dressing and nothing changed. Possibly a bearing going bad on one of the pulleys?

 

[treats54]

No, I am not sure they are related. In listening more, it sounds like it might be coming from the belt area, but applied belt dressing and nothing changed. Possibly a bearing going bad on one of the pulleys?
The squeal will stop after turning the air flow switch to off from inside the cabin.

 

[pet575]

The belt dressing won't change anything if a pulley bearing is going bad. You have to squirt some Liquid Wrench or something like that into the bearing area on the pulley to see if it quiets it down. Sometimes that doesn't even work.

Interesting that it stops when you change that switch position, though. Makes me think these conditions are directly related and that the noise you're hearing is some type of air/vacuum leak.