Pentium

This thing has been the biggest pain in my ***. I cannot for the life of me figure out how to get rid of it, and is literally driving me insane.

Whenever the engine is cold, the thing squeaks/squeals like mad until the engine is warm.

The first time, I replaced the belt. Went away for two weeks and came back. The alternator was making a loud whining sound occasionally so I figured that was bad. Replaced the alternator with a new belt AGAIN. Sound came back after 3 weeks.

It seemed like the tensioner was going bad because I pulled it off and the bearing seemed tired. I replaced the tensioner/pulley assembly and slapped a new belt on there. Squeal came back after a month....

Next, I replaced the water pump and another new belt. Came back after a month.

Next I tried cleaning all the pulleys since they had some gunk on them, and replaced the belt again, same thing. I have tried a total of 6 belts in 3 different sizes, nothing seems to be making a difference and I've run out of hair on my head to pull out. My mechanic says "Just deal with it" but it's easy for him to say...when you've heard this loud squeal every morning for almost 3 years, you'd run out of sanity and patience as well.

Does anyone have any ideas? The steering pump, A/C, and air pump haven't been replaced and are stock but my mechanic expert seems to think that all the bearings are in healthy shape. The alternator started making that loud whining noise when the engine is started warm, I'm guessing because of the belt issue?

Red1995f150

Maybe you have coolant/PS fluid/ oil leaking on belt very slowly. I used to have an old Mitsubishi that had an extremely slow leak and I replaced the belt only to have it happen again like you say.
You can get UV dye from Napa for a few bucks put it in the system. Run it to get it through everywhere. Then at night use a flashlight with a blue lens (Wally world/target) to check thoroughly for leaks.

Rod Wise

I recently developed a squeal after replacing belt with a new one (what was I thinking!?). I zeroed in on the exact area by giving a shot of silicon lube straight into pulleys until I found the culprit (alternator). Of course, you have to use the little plastic spray hose on the end of your nozzle, so your not getting fingers by the fan blades... So now I've ordered the entire alternator ($70 vs $20). I figured looking at alternator it's pretty old so might as well. Now I'm paranoid I'll be chasing ghosts like you!

93Bandit

I've been chasing a "belt" squeak for the last 5 months and finally found the culprit. It would only squeak when it wanted to, cold/hot, low rpms, high rpms, chirp occasionally or scream bloody murder. Finally isolated it to the smog pump. I took the belt off and when slowly turning the smog pump pulley I can hear it squeak ever so quietly. I sprayed some WD40 in the bearing and the squeak went away for a few days.

I suggest you do as Rod Wise advised and carefully spray lube in each accessory until it stops.

If you're unable to determine which pulley is squeaking and begin to suspect the belt is slipping causing the squeak, you can wipe a decent sized glob (about the size of a penny) of dielectric grease on both sides of the belt and run the engine for a while to cover the whole belt. Don't try to wipe it on while the engine is running!

Bigred1996

I would check each pulley by pulling on each of them back and forth to see if it has any play in it. If one of the pulleys have play in it that's your problem. just a guess because its never happened to me.

east302

Did your mechanic check the alignment of the pulleys? Many shops have laser alignment tools that can quickly check to see which pulleys are not lining up. You can (sort of) accomplish the same thing with a straightedge and digital caliper. Lay the straightedge across two points on one pulley. Measure the distance between the straightedge and a groove on that pulley. Keeping the straightedge on that same pulley, now measure the distance between the straightedge and the same groove on an adjacent pulley. They should be equal if everything is aligned.

Check youtube, there are videos that probably explain it better than I can.

The power steering pump is one possibility. If that pulley isn't seated on the pump shaft correctly, it can throw the belt alignment off. I believe the pulley flange is supposed to be flush with the end of the pump shaft.

Rod Wise

Here's s really good video on how to track down your ghost:

1991f150jason

ive been trying to figure it out for a while as well, and my alternator is making the noise as well, so I am going to get a new alternator, but it was also my air pump. my air pump actually just seized up on me and now my truck is sitting until I can get a bypass pulley, and im just taking out the air pump completely since I don't even have cats and its just sitting there. mine would pop and squeal, and it would either be a chirp or a squeal to high heaven. so make sure everything is cleaned and the right belt and everything, but im taking out my whole air pump because its basically just sitting there taking up space. hope this helps. got my replacement pulley off cjponyparts.com. and make sure you get the right size belt and everything but you know that haha

Pentium

THANK YOU everyone for the replies! It was the damn air pump! The thing was very worn out, and not only causing the squeak but a slight grinding noise. Instead of gutting it, I just bypassed it. Installed it the same way as the A/C delete method, but included the A/C. Measured it out with string to about 81" so I bought an 810K6 belt and threw it on there. Not only is the squeak gone, but the engine is quieter and runs more smoothly in general.

It may be placebo but it seems to have a hair more power

The frustrating thing is, when the cat was replaced before I bought the truck, they never hooked the air pump up to the cat! So not only was it causing me grief, it was never doing anything in the first place! I have been passing emissions, so I'm not worried about it at all. My truck is OBD2. I'm guessing my gas mileage will be better now as well. Cheers to all of you, and I hope this helps someone in the future