squeaky chirping sound from under the hood

[mixwhit]

I've got the 4.0L V6 w/ 158k miles. Got it used a week ago. It just developed a rather loud and annoying squeaky chirpy sound. When I first start it up cold I hear it on idle, but once it warms up you don't hear it during idle anymore. However, if you step on the gas then you hear it no matter what the engine temp is for as long as your stepping on the gas.

I did some searches and read about this possibly being the cam synchronizer or cam position sensor. So I got a friend to hold the gas pedal down while I used the garden hose to the ear trick to try and pinpoint the sound. I couldn't isolate it to that area (back of the engine). Frankly, I couldn't isolate it at all other than I think it's coming from the engine area.

I thought it could also possibly be a belt, but it doesn't seem to be coming from there either.

Ideas? I'll probably give my mechanic a call, but if it was something I could easily handle myself I'd give it a shot.

 

[pillen140]

that really sounds like a belt, or tensioner. but i dont know

 

[87Ranger4me]

Try this, while it's running and making noise spray some water from a hose on the belt, if the noise stops, it's the belt, replace it, don't use belt dressing on a serpentine belt. If not look elsewhere, like the tensioner.

 

[dennis461]

the belt has my vote.
"..don't use belt dressing on a serpentine belt.."
It did not stop my squeak, wasted 3 dollars on the spray can.

 

[mixwhit]

Try this, while it's running and making noise spray some water from a hose on the belt, if the noise stops, it's the belt, replace it, don't use belt dressing on a serpentine belt. If not look elsewhere, like the tensioner.

so you're talking lots of water, not just a bit it sounds like?

thanks everybody for the replies

 

[stock95ranger]

sounds like a bearing going out in a tensioner or idler pulley to me.

 

[mixwhit]

solved

Indeed it was the belt! I replaced it today and the noise is gone.

I also tried spritzing it with a spray water bottle while running before I replaced it, and the noise instantly went away for a few seconds. So that is a great test to see if it will fix the problem. While I had the belt off I tried all the pulleys individually and none made any noise of their own.

thanks for all the help!