This incredibly annoying squealing sound started a couple days ago on my way home from class. I'm 95% sure it's not the serpentine belt, it sounds more like a pinhole in a hose. I've disconnected several hoses from the intake and sprayed a little water on some other hoses while it's running trying to at least make the sound go away or change pitch for a couple seconds. No luck. Here's a video I took this afternoon Any ideas? This sound is driving me insane. It kinda sounds like when you let air out of a balloon really slowly

 

Have you sprayed water on the belt itself and see if that changes the sound? If not, next thing I would do is take the belt off and at least eliminate or narrow it down to the acc. drive area. FWIW I have seen some of the ford ranger v6 idler pulley bearings make some funny noises.

 

It's definitely not the belt. I used a long screwdriver as a stethoscope to find where the sound is coming from and it's coming from the intake. Took a flashlight and looked inside and my plenum is blown! Just spent $600 this past July to replace the plenum with the Hughes kit. That explains this vacuum leak sound I've been hearing. I'll be having a talk with the guy that did the repair this week..

 

I was thinking that you might try a simple trick to see if that vacuum leak is one of the vac lines. Just spray some carb cleaner over the area with the motor running. It should cause the motor to change idle if there is a leak sucking air. If its a blowing leak you should notice the stuff being blown away.

I thought my Hughes plenum kit failed too. It was the crank Case vent letting blow by make it to the air cleaner and an after market air cleaner letting it go over and under. Now I only use the NAPA high quality air filter so nothing gets by over or under.

 

well I sprayed carb cleaner all around the intake and surrounding hoses and no difference. I also took the air cleaner off and it didn't look dirty like there was oil getting past.
Another thing to add- since the sound started, the engine has been idling a little bit higher (about 800-850 rpm opposed to about 600-650 rpm normally). It also is bouncing a little bit and does not maintain a constant speed- I'd say it fluctuates about 50-75 rpm constantly. It also rev hangs when I press the clutch, which it has never done before.

 

Have you checked your distributor?

 

No. Just did plugs and wires but I have not touched the distributor since I bought the truck two springs ago. Can they make noise when they begin to fail?

 

Quote:

Originally Posted by tomgreene

No. Just did plugs and wires but I have not touched the distributor since I bought the truck two springs ago. Can they make noise when they begin to fail?

Yes, they can.

 

I would pull the cap and rotor and look for damage. Just a suggestion. But if the rpm's are higher then normal, that does sound like a vacuum leak....... You said you checked the hoses, what about around the base where the throttle body bolts on?

 

Tom,

I am going to start over and tell you what I would do, if that was my truck. Some of this may seem to be nonsense, but again, its what I would do.

1. Take the serpentine belt off, and start the truck. If the noise goes away, start checking alt. ps pump, ac pulley, idler pulley, etc. these all have bearings and if dry, could make the high pitch noise on your video.
2. Assuming you still have the noise, I would look in the distributor and see if you can tell that something is rubbing or shavings of metal.
3.After all of that, I would try to unplug each injector, 1 at a time to see it that makes any difference.
4. does the 96 have a fuel regulator up by the intake? If so, look at it.
5. if all of this checks ok, and your pretty sure its coming from the manifold, I would start taking it apart, look for a bad gasket, crack, etc.


One other thing, try taking a 3 ft piece of heater hose, hold one end to your ear, and use the other end around the motor and see if you can pinpoint the source of the sound


Once you find it, be sure to let us know what it is!!