# Engine speed whistling sound **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mercury, noises\ **Created:** [December 10, 2010, 2:20pm UTC](https://community.cartalk.com/t/engine-speed-whistling-sound/58506 "2010-12-10T14:20:53Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![blairthomas](https://avatars.discourse-cdn.com/v4/letter/b/c67d28/32.png) [@blairthomas](https://community.cartalk.com/u/blairthomas)\ **Post date:** [December 10, 2010, 2:20pm UTC](https://community.cartalk.com/t/engine-speed-whistling-sound/58506/1 "2010-12-10T14:20:53Z")
Variable pitch whistling sound that changes with engine speed. Not consistent. Sometimes accelerating quiets it other times decelerating calms it. Happens with A/C on AND off. Changing serpentine belt did not work. If ATF were low could tranny be causing this? Belt tensioner? Alternator bearings? When car has been 15+ miles the sound goes away. ---
**Author:** ![mleich](https://avatars.discourse-cdn.com/v4/letter/m/71c47a/32.png) [@mleich](https://community.cartalk.com/u/mleich)\ **Post date:** [December 10, 2010, 2:25pm UTC](https://community.cartalk.com/t/engine-speed-whistling-sound/58506/2 "2010-12-10T14:25:34Z")
My guess without seeing it would be a belt tensioner. It could also be a water pump, power steering pump, or anything else attached to the accessory belts. Click and Clack recommend making a " car stethoscope" out of a length of hose and a funnel so that you could determine exactly where the noise originates. Are you the Blair Thomas from Penn State? ---
**Author:** ![jesmed1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/jesmed1/32/2097_2.png) [@jesmed1](https://community.cartalk.com/u/jesmed1)\ **Post date:** [December 10, 2010, 4:18pm UTC](https://community.cartalk.com/t/engine-speed-whistling-sound/58506/3 "2010-12-10T16:18:11Z")
Whistling sound suggests a vacuum leak. Check all vacuum hoses and connections.