xj_or_bust_99

My 00' XJ sometimes will start making a whistling noise, kinda like when you have a bad ground in your radio and your speakers make a whistle noise. So I thought that was the issue until one day I got out of my jeep and left it running and noticed the whistling was actually under the hood so hears what I know. It comes and goes, somedays it doesn't do it ever or even weeks ot won't then randomly it starts again, only makes the noise when no throttle, if I'm driving and pushing the pedal ot goes away but as soon as I let off the gas its back, seems to be louder on the left side of the engine bay but haven't been able to pin point the source. Any one have any ideas because the past week its been an every day thing and its getting really old and its really a pretty loud whistle noise outside the vehicle. HELP!!!!

mud-dog27

engine bay whistle is kind of a vague description......but i would tell ya to check your pulleys, the bearings may be about to **** the bed. When you say left how are you looking at it, cause general rule of thumb is always look at it as if your in the driver seat driver side = left passenger side = right.

A way of narrowing the area down is take a screw driver or bar of sorts and put it on a solid surface thats not moving near the pulley or on it if possible and while holding it in your hand put your ear to it, or if ya want you could invest in a mechanics stethoscope as thats the proper tool. If it is simply a pulley bearing see if the bearing is removable then you just get the bearing number and swap in a new one, that way its a couple dollars for the bearing as opposed to price for a complete pulley assembly.

UJSLOST

whistle is very vague! But when someone says whistle under the hood I automatically think of a vacuum leak.

kjc

My '93 whistles from the engine compartment too.. only when cold started (goes away after a few blocks) This thing sounds like a train whistle. Think HO scale, not a real locomotive. Pretty quiet really. But if I play with the throttle a little from idle to 1000 rpm, I can make it go woooo wooooo just like a train. Kind of a dopplar effect. No problems, no vacuum leaks, it doesn't bother me really. I'm just curious as to what it is. Maybe similar to yours.

awsgrayrd

x2! Definitely more info to help...

V/r,
-Gray.

xj_or_bust_99

Yea I say left as in driver side have stethescope and checked pulleys before had the alt pulley seize and broke the belt when that happened the pwr steering pulley cracked so I replaced the Altenator and installed a new pwr steering pulley all other pulleys are fine . The reason I say whistle is because it is a whistle not a whine or houling noise but a whistle. Vaccum leack is what I was kinda thinkin as well. But when its whistling its driver side mid to rear of motor seems to do it when it cold out more so then warm days should I start checking/ replacing vaccum lines if worn cracked or any oher damage. I'm a Suzuki certified motorcycle tech so some of my usual leak check tricks don't always work on cars due to all the other components crammed into the engine bays. But also wondered about the intake manifold gasket, tb gaskets are new and I'm about to replace the valve cover gasket so maybe ill replace the intake and exhaust gaskets too I kno on bikes and quads u can get whistles from intake leaks from carbs/ tbs not being seated into boots properly or broke gaskets but on bikes u usually get running issues that help use trace back the problem my jeep runs fine so didn't have any good place to start

chill

If you bore out a throttle body they wistle. check the the throtle body gsket, or the shaft that goes to the butterfly. could be warn.

wikiwaugh

Cold air intake would whistle, but that's expected lol - check your vacuum bottle?

1991Jeep_Man

Check your water pump. Been there, done that. Would whistle randomly, at various rpms. Replaced it, and no more whistle.

xj_or_bust_99

Had a cold air intake before and it was a Lil whistle but the other would be louder when it would start whistling, water pump is only 2years old but ill check it out and see

soundrew

I have a similar whistle. I've only had the truck for a few days and noticed this occasional whistle on deceleration or idle. I think it is vacuum related or perhaps power steering pump bearing. I sprayed ether on the throttle body gaskets, vac lines etc and no increase in idle speed. Hmm. I'll let you know if I find it.