2000 Chevy Malibu whistling sound from under the hood?

Maintenance/Repairs
1

The whistling sound is fairly straightforward but there are little details that are weird.

I noticed maybe 1 or 2 weeks ago that the car would make a whistling sound, not a high pitched one but a fairly middle-high sort of tone. It would make this sound when I put the car and drive and maybe just start to gas it but NOT all of the time. By the time I am at a regular speed it has gone.

But sometimes when I slow down the sound will return and go away when the car has come to a complete stop. But this is not a constant pattern. It is on and off. Only recently could I say it has become more frequent but even then I hesitate.

Also the sound seems to definitely be coming from under the hood possibly from the back of the car but I think front may be more likely.

I read briefly on a few car/car repair forums that it could be anything from an AC compressor going out, a vacuum leak, fan belt, bad water pump, among others. I tried turning the AC on, which I have kept off for pretty much the entirety of the Summer and I heard the sound only once when I resumed driving. BUT, when I revved, the engine seemed noticeably louder; almost like it was laboring though the car drove just fine.

One other thing. Before it sounded as if the origin of the whistle was coming from the passenger side of the car. Just as of today it sounded as though it originated from the driver’s side. So I’m really confused now.
The car seems to drive just fine and the engine the day before sounded good if not great. I’m hoping it is nothing related to the engine.

*Few Notes:
The oil was changed in June
The tires were replaced recently. Though the sound started before this. I was however driving on a really bad passenger side tire for a while.
There is a short on the panel that contains the left turn signal. The bad bulb was changed and I plan to find a new panel as soon as Monday.

I greatly appreciate any ideas as to what the problem is. I tried to be as detailed as possible but if you need more please let me know.

Thanks.

*Also, sorry for the long post. It’s just that I felt the details to be very important!

2

Does this sound appear only when driving, or also before you even put the shifter in drive.

If it will do it while In neutral…you could have someone else start the car while you listen.

One trick is to use a short 2 foot piece of hose. hold one end to your ear and direct the other end.
When you get close to the problem you will hear it better thru the hose.
Use caution near moving parts!!!

Yosemite

3

My car whistles over the radio with weak am stations, I put on the brakes and the whistle starts high then decreases in pitch as I am stopped. If you turn your radio off is it still whistleing? Vacuum leak somewhere if not radio related. Now everything has been running fine so I just accept the whistle on am as an eccentrenticity.

4

I found a whistling under the hood that was driving my wife crazy several years ago. I drove the car ('93 Cutlass Ciera) for an hour before finding the culprit. It was caused by an aluminum disc on top of a Stant radiator cap. Pressure was leaking out and causing the whistle. It’s a long shot but I included a picture: