Whistling noise on my 99 L when I crank it up.. I don't know where this is coming from...I notice it even during normal driving and sounds different from the popular supercharger whine.. I saw someone mention that the trucks make a whistling sound when there is a vacuum leak. I have lost some power/torque so if this is the case what are the common hoses where leaks can occur?

Thanks!!

 

Sometimes aftermarket throttle bodies whistle. Is your TB stock?

 

A wind whistle or a bearing whistle ?
Belt idlers can make that kind of noise. And they are easy to check. just reach in there (whith the motor off) and see if the can be moved.

 

I had a strange whistle...turned out to be loose window moulding on the top of my windshield.

 

I had a noticeable whistle for weeks and could not find it. Finally the motor started spewing antifreeze out the overflow at WOT. It was the head gasket.

 

I have the same problem on my 99L. It kinda sounds like its coming from the supercharger. Not sure if its the bearing inside or idler bearings. Can you change out the idler bearings?

 

i had a whistle (high pitched). it turned out to be my airbox. i had my k&n panel filter zip tied to the top of the air box. i didn't use the bottom half. the squeal was air passing between the panel filter and the airbox.

 

it's definitely coming from under the hood..Sounds slightly like a kettle whistle.. At WOT the truck pulls decently but just normal acceleration feels very very sluggish ....On cold starts the whistle is very noticable

 

I had a whistling noise once..then I realized it was actually me...whistling

 

Sounds like a vaccum leak....break out the carb cleaner, check those hoses...it can and will make the tune run bad.
wjm

 

Wasn't there something mentioned on this a while back about the stock throttle body not being matched up very well with the intake on the SC. Someone mentioned they removed the Tbody dremmeled the opening just a slight bit to match the tbody and all was fine.

I get the same whistling sound only when it is very cold out.