DISCLAIMER: This is going to sound stupid at FIRST, but hear me out.......

1998 F150 XLT Supercab, 4.6 Manual

Issue:
Chirping coming from the front of the engine.

I did the old spray water on the belt trick and the noise went away.

I figured it was just the belt because the current serpentine belt was pretty bad, but no. I've replaced the serpentine belt, idler pulley, and tensioner. Squeaking is still there. I watched the pulleys for runout, but everything is running straight as an arrow. The ONLY thing I can see is the belt "walking" maybe 1/8" side to side on the idler pulley. I tried replacing the already new pulley with another, thinking that maybe it's out of round......but the issue persists. All of the accessories are bolted down correctly so they SHOULD be in alignment with each other. I took the belt off and wiggled each pulley to see if there was any play in the bearing. None. I spun the pulleys by hand, no noise and they feel great. I can rebuild an engine, but I can't find the source of this damn squeak. Again, spraying the belt with some water removes the chirping completely temporarily.

Any ideas? Am I missing something here?? I would love any good suggestions. This is driving me nuts and I'm going crazy listening to the damn thing chirp as I drive.

Someone suggested getting one of those Gator belts, I think they're made by champion, but I cannot find anyone who sells them.

 

Failing harmonic balancer maybe?

https://www.rockauto.com/en/catalog/...+balancer,5512

 

BareBonesXL:
No, it's definitely something to do with the belt. Not that the belt itself is bad though. I know this because when you spray water on it, it completely stops. If the noise didn't stop, then it would likely be a bearing going out somewhere. It's really throwing me for a loop to be honest. It's something that should be simple to identify, but has been anything but. I'm going to try to get a laser on it to check alignment, just for good measure, but everything looks good by eye and is "right and tight."

 

If the damper pulley is misaligned or slightly tilted because the rubber is bad it will cause the belt to "walk". Which you described as a possibility. The misaligned belt might chirp as it hits the next properly aligned pulley.

Regardless, it's easy to check. Then you can be certain. Good luck.

 

It looks like all the pulleys are aligned properly to one another. I checked them with a laser. IF they are not, it would be by such a small amount that I can't even measure or notice it. I took the belt off and felt all the pulleys. The power steering pulley has some forward to backward play, but everything else feels good. While running, with the belt on of course, all the pulleys are tracking straight as an arrow. The ONLY place I can see the belt move is on the idler pulley. It travels front to back (as in front of the vehicle to the back of the vehicle....not sure how else to reference it) maybe 1/16th of an inch. It SEEMS like the squeak is coming from this.

Here's where it gets weird.......

I took the belt that was already new off, replaced it with a different brand, and the squeak COMPLETELY went away. Not a single chirp. I was ecstatic because this has been driving me nuts. I drove a few miles to return some parts and then the squeak came back. I mean what the ever loving F is going on?? I swear this truck is driving me to the brink of insanity.

I attached a few videos to show what i mean.

You can see that when I spray a little water on there..... no squeak. So it shouldn't have anything to do with bearings. It SHOULD be something to do with alignment or the belt, but I have already tried two new belts of different brands, replaced the tensioner and idler pulleys, and done everything else I already mentioned. ???????

Any thoughts? My truck sounds like a pile of garbage going down the road.

 

Maybe it's something starting to lock up like your AC compressor. Is AC on when you're doing this? Don't forget that the AC compressor runs with defrost and other climate settings. Test with the **** at Off.

 

That was a thought, but I had already checked that.

SO, I did finally figure it out. It was in fact the harmonic balancer. I didn't notice, but the outer piece had shifted rearward about 1/16". It was actually starting to cut a groove into my timing cover!

Anyway, I replaced the harmonic balancer and all is good now!! I appreciate the help.

Now I just need to figure out the electrical issue, rebuild the EVAP system, and replace some parts of the frame. LOL ughhh.... At least I got 1 win.