In the last month or so I have been having a noise. It will occur if I am waiting in the car for a couple of minutes, but in todays heat it did it all the time. If I rev the engine as the rpms are coming down it makes a noise. The best way for me to describe it is if you have an old drill and rev it up when you let off the button as it is slowing it will make a noise. With the drill I always associated it with dried out bearings. I took it to the dealer today for its yearly service and they said they could not duplicate it, funny since I can do it on cue. In the picture below it looks like there is something that looks like it runs off the crank pulley by having another wheel up against it. Does anybody know what that is?

 

I think my brain got fried from the heat today. I just answered my own question. It is the water pump, but I don't think that is making the noise. Does anyone have an idea?

 

when i down shift into second it makes a weird noise sometimes but only when im canyon driving. I cant explain the noise but the dealer has no clue.

 

I sometimes get a weird noise from the airconditioner compressor under similar conditions. Its a sort of whirring noise that descends in pitch as the engine slows. It happens, then it goes away. I've decided that its a belt noise or perhaps something that originates from the idler pully as the strain of the compressor puts more pressure on the belt.

It has never seemd to affect anything and it comes and goes. Its worse when the humidity is high. I don't think ambient temp outside has much impact cause its pretty warm under the hood no matter what.

Next time, try moving your air conditioner switch to "Max" and see it that changes anything.

 

I have heard a noise that really fits the description by Herlman. Sounds like something spinning down. Happens every now and again. More so in the heat.

 

I had a whine very similar to that when I eased off the gas pedal. I had my HPFP replaced via warranty thankfully ($1200 FWIR) and the whine was gone. Not sure if they are the same noise. Have you tried to diagnose where it is coming from by having someone else ease on and off the pedal w/ the bonnet open?

 

It seems to me that with the bonnet open it is low on the engine somewhere between the engine and the firewall.

 

how is your oil level?

 

Tell you the truth I haven't checked in a little while. Although it was just changed yesterday and did it before anf after the change.