Mechanics

WRANGLER , 2.5L WITH HIGH PITCHED

1999 Jeep TJ • 11,000 miles

Hello,

I have a high pitched whistle noise coming from my 1999 2.5L Jeep wrangler. Noise is heard mostly at idle.

The noise GOES AWAY when I take off the fan belt, so m not a vacuum leak. I have now replaced ALL of the components attached to the belt (alternator, water pump, pulleys, power steering, fan clutch) and the noise still persist. Its really driving me nuts that I can't figure out what it is. I would like any help.

Also, due to the colder weather coming in, i have noticed that the pitch of the tone increase when I put on the heater in the Jeep. I'm not sure if its connected to the heater or just because turning the heater on increases the RPMs slightly.

Could it be electrical? Here is a video, all suggestions are appreated; http://www.youtube.com/watch?v=BiG9syxz6…

THANKS!!!
AD
Avatar
JeepTJ1999
October 15, 2012.



It cold be the fan sucking air in through teh radiator. Also did you replace the belt tensioner and the belt? If you can shoot water on the belt and the noise goes away then the belt needs replacing as well as tensioner.
AD

Hmac300
Oct 15, 2012.
Yeah, i've replaced both the tensioner pulley and belt. Sound remains. As for the fan sucking air in through the radiator, i've taken the fan off and ran the engine and it still remains. This noise is so hard to find, i'm really out of ideas.

Tiny
JeepTJ1999
Oct 15, 2012.
It might be a vacuum coming through throttle body or a line off someplace, normally those make teh whilstling sounds. You might look and see if anything is rubbing as well, like a small piece of metal, like sheetmetal. I'd have to hear it live and can't hear. The youtube sited didn't work. But it wold be to hard to nail down in here anyhow.

Hmac300
Oct 15, 2012.
Check the harmonic balancer as well. Note if the crank pulley is moving in a wavy manner.

KHLow2008
Oct 15, 2012.
Thanks for the replys! If it were a vacuum leak in my throttle body, or anywhere else. Wouldn't the sound persist even when I take the belt off? Please remember, when I take the belt off, the sound goes away and i've already replaced everything attached to the belt.

Thanks!

Tiny
JeepTJ1999
Oct 15, 2012.
Ya it probably would but I really can't think of anything else to tell you either.

Hmac300
Oct 15, 2012.
Have you checked the crank pulley?

KHLow2008
Oct 15, 2012.
The crank pulley is original. It has no cracks on it as well as no play in it. Makes no noise when the belt is removed and engine is started. Do you think this could cause noise under the stress of the belt?

Tiny
JeepTJ1999
Oct 15, 2012.
It mighit if it were loose or broken. You might put a chalk mark accross it, like staright accross, then give it ia quick rev and see if the lines match up. If not then the rubber is broken and needs replacing.

Hmac300
Oct 15, 2012.
My 2.5 had a high pitched whistling noise and the exhaust header bolts had worked loose and I tightened them and solved that irritating noise. May help you.

Tiny
Drdetail66
May 4, 2013.

AD