Squealing under throttle

[tatersalad]

Went to put some fuel in my rig today and noticed a squealing noise from under the hood if I Rev the motor.
So I get it back home and start looking at the serpentine while revving it, and it seems to sound more like it is coming from around the back of the motor. The 351W is efi and has around 3 to 4 k on it as does the c4. I tried putting a bar of soap up against both sides of the belt with it running and that didn't stop it. It has never done this previously. The rig has been garaged a while but I do let it run up to temp and pull it out around once or twice a month. Any suggestions?

 

[00gyrhed]

when you find it let me know what it is. I have been looking for 3 years now. I have replaced all gaskets, I have even pulled the intake and pressured it up with blank off plates looking for a leak in the casting.

I originally though it was a belt thing but I can pull the belt and still get it. I have been over ever place there could be a vacuum leak with a fine toothed comb. Hoses have been replaced, you name it. I just gave up and kept driving it.

Funny thing mine didn't start until I put the Hydroboost on it.

 

[jeff_gates]

I had replaced my fan with a flex fan. I found that under load the blades would shift their angle and put stress on the water pump and belts and cause a squealing noise.

I switched to an electric fan.

--Jeff

 

[tatersalad]

I'm running a Taurus fan. The serpentine always had a slight squeal but this seems to sound like it's towards the back of the valve train or possibly the converter area.

 

[00gyrhed]

mine will also whistle when I shut it down but wont be whistling at idle. turn off the key and it whistles until the manifold bleeds down. I guess anyway. Mine is not the belt makes the noise with the engine running and no belt.

 

[00gyrhed]

I'm running a Taurus fan. The serpentine always had a slight squeal but this seems to sound like it's towards the back of the valve train or possibly the converter area.

me too, I blamed mine on the throttle body, idle air valve etc but it really does sometimes seem to be coming from the firewall behind the throttle.

Sorry I don't mean to hijack this but I have been chasing mine for years, I will just tag along and hopefully someone will give it a resolution.

 

[tatersalad]

Well I eliminated the serpentine and it's not gone. I'm wondering if I have a rocker not getting oil on the driver side. When I started it up a couple months ago after it set for a while I did hear a tic like a lifter. This is going to drive me nuts.

 

[tatersalad]

One other thing is it started happening after I put on a 1 " body lift. I started getting the squeal and an intermittent code for hego

 

[tatersalad]

This thing is driving me mad. It only is happening when the rpm is around 2k and up.

 

[tatersalad]

I think I've figured it out. The fact that it is throwing an intermittent hego code on the side it's coming from, I'm thinking it's an exhaust leak at the header. I've never heard one squeal like this before but I have never ran the aluminum multi layered gaskets either. I am going to re tighten the header bolts when I get a brake from these triple digits. I'll let you know if that works.

 

[LouisT]

Had pretty much the same thing happen once but mine was more at idle during some engine work. Check if the oil filler cap on the valve cover is not blocked and/or has a strong vacuum under it. I've run a non vented cap to cover the hole while working around the engine just to make sure nothing fell into the opening. Makes the same noise you're talking about and the cap is stuck down so tight you can't pull it off. Your first thought is its a bearing or the water pump but it was the cap sucking air!