I have a 1994 f150 5.0 liter with 250,000 miles that has an annoying belt or pulley squealing noise. I replaced the idler pulley and the tensioner pulley and still had the noise. I then replaced the belt and the noise completely went away, for 1 day. Today I drove the truck to work, 8 miles and no noise. This afternoon on the way home the squeaking started coming back. Under load and accelerating the squealing is pretty bad but when I stop to idle the noise goes away. Before replacing those above parts it was pretty much a constant squealing noise but now only when accelerating or reving the motor. Could it be caused by the tensioner spring not being tight enough? Can't really locate the noise, had a guy from autozone try the stethoscope but he couldn't find it either. I thought the new belt had the problem solved but wondered since it gets quiet when idling and only makes noise under load if maybe not enough tension to keep the belt tight during a load could be the problem, any suggestions?

One other thing, I removed the AC compressor and replaced it with a bypass pulley because the AC pulley was locked up and I didn't want the cost of having to replace that unit so I just removed it about a month ago, and no noise issues until the last few days.

Thanks for any suggestions.

 

A quick follow up, I replaced the tensioner arm and pulley yesterday and the squealing went away, again for about a day. Seems like anything I do to the belt stops the noise temporarily until the motor gets warmed up or the ambient temperature is warm. Again, makes the noise only when accelerating or under load, stays quiet during idle. Any help or ideas on what to check next would be greatly appreciated. I'm trying to keep the cost down on getting this fixed as I have a low fixed income right now. Please, any ideas are welcome!

 

With the engine cold, wash the belt & the front of the engine with something like Simple Green, or Purple Power for a few minutes, followed by a LOT of water. Then rinse some more with the engine idling, especially on the belt. Let it idle until it warms up & dries everything off. Then see if it still squeals.

What brand of belt did you install?

 

I got a Duralast belt from Autozone, they had 3, valuecraft-cheapest, duralast-midprice, and couldn't remember the highest price brand but went with the middle of the price range. It really made it quiet for about a whole day, trip to work and back but chirping started the next morning and get progressively worse under load.

I did notice yesterday that the tensioner pulley is not completely in line with the other pulleys, it seems to set at just a bit of an offset to the other pulleys. Doesn't seem to be a way to adjust it to get it to line up exactly.

I did wash the pulleys and the belt yesterday afternoon and it did work for a little while but on the drive into work today the squeaking is back, again just under pull or load, not during idle. I will try and give it another more intense cleaning this afternoon.

Is there supposed to be some way to adjust the angle of that tensioner pulley? If I seat both bolts all the way in then the belt rides on the outside (fanside) edge of the pulley, if I back out the bolt with the hex/star that holds the tensioner to the engine then it gets the belt back to the center of the pulley but the pulley itself is still offset to the other pulleys, just about 1/8th or 3/16th of an inch off but enough to notice eyeballing along the other pulleys. Doesn't seem to be a way to get the bolt to go in far enough to let the tensioner pulley get into proper alignment. You can tell it comes off the bottom pulley into the tensioner at just a bit out of line and also comes from the tensioner to the alternator at the same bit of offset, not much again but not dead center to those other two pulleys. I have ordered a Gatorback belt from RockAuto as I have heard they are better at handling misalignments that other belts. I have tried the Autozone Duralast tensioner and also this latest one is a Dayco No SLack from Advance Auto parts but they seem to be identical with that slight offset problem. Again, backing out the hex/star bolt from the engine block got the belt running in the center of the pulley but not the pulley itself in alignment. I could see where this slight offset might cause problems but at a loss at to how to adjust that pulley. Thanks for the reply and I welcome any suggestions.

 

Take all the Duracrap back and get your money back. Stay out of the zone.

If you still have the stock tensioner, transfer the pulley to it and check the alignment.

But I don't think that's causing the noise. Next time you have the belt off, inspect the pulleys CLOSELY with a bright light to look for signs of heat, wear, or glazing along each rib. Use a wire brush, wire wheel, or coarse steel wool to scuff any shiny polished spots, and remove any varnish.

 

We'll do, I'll try that this afternoon.

Are the parts at AdvanceAutoParts OK or do you recommend a different supplier. Those two are the closest ones to me but I thinks there's a NAPA a few miles further away.

Looks like RockAuto has all different brands and of course the Motorcraft parts are always the most expensive. I try not to get the cheapest but also try to balance that with not going overboard just for a name.

 

All parts stores carry some cheap lines, but the zone pushes them moreso than other stores, and carries VERY few good lines. I also have several personal beefs with the zone...

Advance & O'Reilly are OK; NAPA, CarQuest, Parts+Plus, & AllPro are better. MotorCraft parts are more than just branded - they're actually significantly better than most others. Yes, many retailers expect you to OVERpay for them, but that doesn't change the facts that 1) they fit, 2) they work better, 3) they last longer. I just changed out a new cheapo turn signal for a Ford part, and the difference was night & day.

 

If you want a QUALITY aftermarket belt, get a Goodyear Gatorback.

 

I ordered a Gatorback belt from RockAuto, hoping it gets here by the weekend so I can get that installed and see if that helps this squeaking.

I cleaned the belt and pulleys again last night and now the squeaking has turned to chirping and intermittent, it seems to go away when the engine gets warmed up and still is quiet when idling. Just wants to chirp now on acceleration when cool and then go away after motor gets heated up. Takes about 5 to 6 miles of stop and go and interstate driving to get it to quiet down. I have one last duralast pulley still on there, the idler pulley, I will probably replace that one with a different brand and then wait for the gatorback belt and see what happens then.

 

Hi Buzz, I have my suspicions about what could be your culprit, but I dont' want to scare you. Firstly did you solve the problem? I am having a similar problem but mine is at idle and goes away when I rev my engine. I am assuming that means the belt is old and needs replaced. I also noticed a slight wobble in the idler. I am guessing the bearing is going out there. Another thing is that the squealing is most prominent when it is wet out, been raining, or there is a lot of moisture in the air. I have tried silicon lubricant, PB blaster and wd40 to quiet the noise. It seems to work for a short while and then the idle squeal comes back. Since it is going on at idle I don't think there are any bearing problems that are presenting themselves under pressuer. Obviously there are at least 4 main bearings in the location of the idler/tensioner and those are the alternator and water pump. I am disregarding the other two at the moment since I am still running cool and alternator is pumping 14.75 amps with a fully charged battery and 13.5 under full load. I am gonna replace both my tensioner, idler pulley and belt this week to see if the squeal goes away. I am seeing good reviews from the Dayco "w" belt so I will try that one out. Did you stethescope your alternator (the water pump might be a little dangerous)? could you let us know if you solved the problem? thanks.

 

I finally got the Goodyear Gatorback belt in and installed it and that seems to have solved the problem. I was giving it a few days to be sure it wasn't something else causing the belts to go bad. The new belt from Autozone worked for one full day and then the squeaking came back. Since installing the Gatorback it has been good for 4 full days.

I would say get a Gatorback belt first and then go next with the idler pulley, and then third with a tensioner pulley. They're not expensive or hard to replace but I would definitely start with that belt first. I finally ended up with a Dayco tensioner and idler pulley and the Gatorback belt and it seems to be OK.

I am still seeing a drop or two of antifreeze occasionally around the top of the water pump but can't seen to find the source, not everyday but maybe every other day just a little bit so my water pump gasket may need to be replaced before long but like you said in your message, it's running cool and the alternator is charging fine.

 

DragonBlod, I am curious, as to what your suspicions were that might be the culprit for my chirping just in case this were to start up again? Thanks.

 

There are actually 3 possibly 4 other bearings on the belt.

*Alternator which is right there by the pulleys
* Water pump which is also somewhat close (and the fans can throw sound)
* smog pump
* and the A/C pump clutch

The last two I would be less worried about. But you should check to make sure everything moves fine when the belt is off.

Your leaking on the water pump I am assuming is around the gasket area not the shaft area. If it is the shaft area I would look into getting a new pump, but I seen another post where you replaced it (had it replaced by Firestone so no way of knowing what gaskets or quality of work they did).

I also noticed you live in a high humidity area, like I do in NE Ohio. This humidity can totally play games with moisture on your bearings.

Check your battery un-connected from the truck for charge. Should be full at over 12.5v and look to see if it is holding charge. If it is below this, get it fully charged. Then do a load test on your alternator. I am not sure what the specs are for it for sure but my 5.8L is pushing 13.54V under full load (not moving) with the A/C, all lights on, radio full blast etc. It is pushing 14.5 volts with everything off except the engine. The reason I mention this is because it can put a load on your Alternator and can show a bad bearing. Also it is a good idea to have your battery fully charged as the alternator is more of a trickle charger than a full charger and can put strain on your alternator heating it up leading to failure as well.

I think the best bet though is to do some preventive maintenance (PMCS) and check all your pulleys.

Sounds like you got it licked though and I think I will look for a gator back belt myself. I been hearing a lot about those. It makes sense that if a pulley is slightly out of alignment, any amount of rub on the belt can cause some squealing, getting worse as the engine is accelerated. Good luck.