recently bought a 97 ford f150 with a 4.6L engine..it did fine for a while but then one day I noticed the belt was squealing a bit when the rpms went over 3000...so I made hubby spray belt dressing on it. It got worse with the dressing. Put a new belt on..it was quiet for about 20 miles then it started squealing worse than it did before the new belt..now it squeals so bad I'm ashamed to drive it. I have tried it with the A/C and without...using the lights don't make a difference. I dont think its the tensioner..what else?

 

Youll just have to check all the pulleys with the belt off. It could be any of them. A bad pulley bearing can make a very loud erratic squealing noise most commonly known or thought to be a belt. When you say you don't think its the tensioner, why is that? Spin all the pulleys by hand with the belt off and try to find the bad ones if any. While the belt is on and spinning, check to make sure none of the pulleys are misaligned, that would tear through a belt in no time. What kind of belt did you put on it? Still think its a bad pulley though. Idler, tensioner, alternator, power steering or a/c. Or maybe even clutch fan.

 

it was just a regular belt from advance auto..$43. We checked the tensioner and the idler they both look good..the A/C clutch is a possibility..spraying the clutch with WD-40 immediately stops squeal for a couple minutes, whereas spraying the actual belt makes the squeal worse.

I also don't believe it to be the alternator because

A) the charge is strong and consistent and I took off the battery cable while the truck was running and it continued to run.
B) turning on lights, A/C, etc. does not effect squeal

There was a problem with the idler..the threads in the block cover were stripped and the whole had to be tapped but a longer bolt and some JB weld took care of that and now its bolted solid. Initally I thought that was the problem when the new belt didn't fix the problem.

 

ahhh..also forgot to mention...a couple days before the squeal started, filled up A/C with R134A..don't know if that could have had anything to do with it or not.

 

I have had a week old alternator, that was performing just fine had some loud squeals on start up and high revs. Replaced and it was gone.
As long as that is holding tight and not causing an imbalance then it should be fine. That would have to be something visual. Or pull the new belt off and check around the edges of it for any glazing or signs of misalignment. As far as the bolt goes, might be easier next time you come across something like that to try a heli coil or insert so there's less risk of damaging/cracking the timing cover. And they hold solid. And can reuse the original bolt pattern.


Also, there are some check marks on the tensioner to tell whether or not it is at the proper tension. I believe they are marks intended to tell you when the belt life has gone bad or stretched. But that could also be used to indicate whether the belt is getting proper tension. In case the tensioner is bad. Something like this



So between that and the A/C issue. Hopefully you find the problemo.

 

going to check that now..

 

I think you have identified the culprit. Either the compressor is locking up with the added coolent or the clutch on the compressor is locking up.

 

did like you said and hubby removed the belt and checked all the pulleys. They were all smooth except the alternator which puts out a squeeking, chirping sound when turned. Its not very loud when turned by hand..could this be the culprit? would it squeal/chirp louder when the belt is putting pressure on it?

 

The sound would amplify under higher rpms. But not sure if that would cause the loudness you have described. The only for sure way to tell would be with a mechanics stethoscope. With the truck running, have someone bring the rpms up to get it to squeal. If a stethoscope is too short (making it dangerous to be in there) to apply to the alternator while moving (since youll be leaning over moving parts), you can use a wooden broom handle about 2' long or so and press it to the top of alternator while its moving, but in a safe way because your ear would have to be on the other end listening. I would still be concerned about the A/C compressor, as they can make some god awful noises when bad. And since you mentioned it happened right after a fill, and became quieter when sprayed, I would wonder about that. You can do the same through the passenger side fender I believe theres room to reach that broom handle in there safely to use it as a stethoscope. Or from just on the underside of the passengers side. Between those 2 you should be able to figure which ones becomes the loudest when the squealing starts. As far as cost and level of difficulty, I would hope its the alternator lol. But from the sounds, it could be either of the 2

 

Providing that the bearings and pulleys are spinning free, your problem is probably that oil has gotten on the pulleys and belt. Since it ran fine for about 20 miles with a new belt, that's the most likely cause. You'll need to take the belt off, clean the pulleys and idlers with alcohol and make sure they are clean. You want to use at least a 70% alcohol available for cheap most anywhere. To do it right, you'll need to install a new belt or expect the issue to come back. Cleaning the belt with alcohol will weaken the belt and cause premature failure.

 

we cleaned all the pulleys last night after we took the belt off. I'm pretty sure he cleaned the belt also, didn't know it was a bad thing. And I am now the proud owner of a new alternator. I can't get it installed till later tonight though...Also

When I went to the parts store I took my old alternator with me cause of the core charge, well when they would go to the part for my truck the alternator they would show me was way bigger than my old alternator. I mean the bolt pattern would match and the pulley was the same, but the body was just larger. The man at the parts store suggested that the guy I bought the truck from might have stuck a smaller alternator on it than was required and that could be part of why the belt was squealing. Idk..I know we found several other things after I brought the truck home..for instance: I don't know what its called but the shaft that goes from the steering wheel to the steering box was broken and held together by radiator clamps, duck tape, and a piece of metal that looked like a socket set holder. It was painted black so I didnt notice it till I had driven it for around 50 miles.

 

Oh EM GeE. If that is the shaft I am thinking of, if it breaks lose.. you will lose all steering. And you can imagine what that will do. I would get that fixed immediately. Never heard of a smaller alternator. I know they offer high amped alternators but they share the same body I believe so I'm not sure where one would acquire a smaller alternator with the same bolt pattern and rib count...Odd

 

thats your intermediate steering shaft, get that fixed asap!!

 

the lightning has/needs one

 

yeah we fixed it real quick. got the actual part at the junkyard for 50 bucks. alternator did not help squeal. went and got A/C compressor today...I'm hopeful.