Idler pulley wobble and slight chirping

[Turtle12400]

I had some pretty awful serpentine belt squealing and just replaced it with a MasterPro belt (K060866), which absolutely fixed most of the squealing. It was insanely deafening at least 100db with the hood open. At one point it actually slipped really bad and I had rubber smell in the cab for a little.

However, I'm still getting some minor chirping, and I think it's the idler pulley. It's wobbling slightly and moves slightly back and forth when I move it without the belt on. The worst of the chirping goes away when I put water on it.

Should I go ahead and replace the idler or could it be that I need a different/higher quality belt?

Here's a video of the idler pulley:

https://drive.google.com/file/d/1YopTrqNfZVpeDCdxebPYSAGXql8EDCwe/view?usp=drive_link

 

[franklin2]

How many miles on the pulley? If it's original, I would replace it.

 

[Curious Hound]

How does it feel by hand with the belt removed? If it's wobbly, replace it. If it doesn't feel perfectly smooth when you soin it, replace it. If you have any doubts, replace it.

 

[pentode]

That pulley doesn't look happy at all - it's the wobble that matches up with the squeak that concerns me. I don't know what the whole pulley costs in your part of the world but I usually just knock the old bearing out and replace with a bearing from the local farm supply that's about $5. Couple blocks of wood and something like a 30mm socket, can't remember offhand. This is assuming the pulley itself isn't bent for some reason.

 

[Turtle12400]

So I got and tried a new pulley and no dice. Same exact squeal. I'm thinking that it's probably just the belt I got doesn't agree with something.

Here's some detail on the diagnosis work I did:

- Tested pulley bearings for play. No play in power steering, water pump, and alternator pulley. Normal play in tensioner pulley
- Checked for trueness of pulleys. All true
- Checked for belt movement at each pulley. No wobble
- Sprayed water on ribbed side of belt. Squeal changes but does not go away
- Sound seems to be coming from the upper pulleys, though I wouldn't be surprised if it's a trick of the sound

It suffices for right now, but I do want to get rid of the squeal. I plan on trying a new belt. Probably a Goodyear belt.

Truck has 116,000 miles on it btw

 

[Turtle12400]

Right now the squeal is pretty minimal. It's not super in your face when outside the truck and basically inaudible in the cab, but it annoys me lol

 

[pentode]

Did that wobble go away when you replaced the pulley?

I feel confident saying a new belt won't fix it... I've been wrong a couple times though.

 

[Bgunner]

Recheck that the new idler pully has no play in it. There should be no movement other than spinning. while the belt is off check the water pump, power steering pump and tensioner for any play. Power steering will have in and out play but none side to side. Clean all the pulley's and retry. Depending on how long the new belt was on before the idler was replaced it could have gotten damaged by the slipping. Best to go over all the pulley's again and ensure they are all good with no odd movement.

 

[SenorNoob]

I love O'Reilly's but their belts for the 4.0 OHV (and I'd bet for everything else) are 1/2 inch longer than what Advance lists for the same application. Normally not a problem, but when I swapped the alternator with one with slightly (like 1/8th) smaller pulley it started to slip. If any aftermarket idlers are slightly smaller than stock, it could be a similar problem.

Yes, I know the tensioner should have more travel than that but it doesn't.

 

[Turtle12400]

Okay so update. Shit is not good.

It's eaten two belts, the belt I got from oreilly on thursday and a napa belt this morning

- There is quite a bit of belt wobble back and forth on a couple pulleys, especially the tensioner pulley.
- I have the belt tensioner nipple towards the outside of the engine (more tension), rather than towards the inside (less tension) if that's important.
- The belt drive pulley coming off the crankshaft seems to be a bit worse for wear. I can get pictures later today, but it's rubber, and it seems like some bits are missing.

I'm kind of at a loss rn. I think the next thing is to try a motorcraft belt or just start throwing parts at it, which I really don't want to have to do. Or go to a shop and have them diagnose it.

 

[Turtle12400]

I love O'Reilly's but their belts for the 4.0 OHV (and I'd bet for everything else) are 1/2 inch longer than what Advance lists for the same application. Normally not a problem, but when I swapped the alternator with one with slightly (like 1/8th) smaller pulley it started to slip. If any aftermarket idlers are slightly smaller than stock, it could be a similar problem.

Yes, I know the tensioner should have more travel than that but it doesn't.

Yeah I was worried about that. Definitely could have something to do with it.

 

[Bgunner]

There shouldn't be any missing chunks of rubber in the harmonic balancer pulley. If there is then it is time to replace it. This isn't to say this is the squeak issue but one that that is found during diagnosis.

When you changed the belts did you grab the pulleys and feel for any wobble?

It is concerning that you mention the belt moves on the tensioner pulley. This would cause a squeak.

 

[Turtle12400]

Yeah the balancer pulley is missing quite a lot of rubber on the edge towards the front of the truck. I just felt the pulley where it's fully intact and there's a little ridge, which is probably supposed to keep the belt on. However, it's missing from probably 3/4ths of the pulley. Probably why it's spitting the belt off?

Tensioner pulley wobble is probably why it's squeaking.

As for other pulley play, there is just a very tiny bit of play in the pulley that's connected to the coolant system, all the way on engine top right idk what it's called. However, the bearing sounds very slightly crunchy.

The PS pulley has zero play besides the usual in and out, but the belt grooves wobble back and forth. I'm spinning it with no belt on rn. But the pulley itself is perfectly in, just the grooves are out.

The tensioner pulley has play, but is no more than the pulley on the brand new part. Also, I mentioned this earlier but is it important to have the guiding stub thing in the little groove on the block?

Alternator is perfect. Zero play and completely in.

 

[Turtle12400]

Harmonic balancer is missing more like all of that rubber rim actually.

 

[Turtle12400]

Okay after some forum scouring I have learned that it is NOT supposed to be like that, and the balancers on 1st gen rangers like to split!!!! SO FUN WOW

Fan clutch nut is so stuck and tried everything but no dice last night. So I drove it to an apparently reputable spot. It's run by a bunch of old guys and the one working on a truck in the shop was smoking a cig, so I think I'm in good hands.

However, it started shuddering and running really weird while driving the 2 minutes to the shop. I'm really worried that the bad balancer did some damage to the internal components or to the trans....having the shop read the codes cuz it threw a check engine light while on the drive there.