so i just got my car back a couple weeks ago from having the engine rebuilt. just before i dropped off the car, i replaced both of the idler pulleys on the A/C drive belt to fix the squealing that was happening. i know it was the pulleys because i would spray some WD-40 into the bearings of the pulleys while the car was running, and it would go away for a short time, until the WD-40 evaporated. the belts were also brand new belts. the pulleys on there before that were the oem ones, my car has never been in the shop for engine work prior to the engine rebuild ever since i bought it with just under 12k miles on it.

so anyway, when i got the car back, i noticed that it was still squealing, but even worse than it was before. i verified again that it was the pulleys using the WD-40 method about a week or so ago, but i just finally got the time to get under there today and check it all out.

what i found is that the bottom pulley (the one attached to the tensioner) was not the same one that was on the car when i dropped it off with the shop. when i replaced them, i bought two of the exact same pulleys for the top & bottom, and now they are two different pulleys. i also noticed that there seems to be a lot of "wobble" in the tensioner...when the car is running without me doing anything, it squeals...but when i put a wrench on the tensioner pulley bolt and push upward on it (so the bottom of the tensioner is pushed toward the front of the car), the squealing stops.

i took both pulleys apart and while they both had some grease in them that was not baked/burnt, there was not much, so i went ahead & packed them both with some high-temp bearing grease. the bolt holding the tensioner assembly to the car also seemed a bit loose, so i tightened that up as well. it did help some, but only after the car has had a chance to get to operating temperatures...when it's first started, it still squeals.

take a look at and let me know if it looks like there's too much "wobble" in the tensioner, and toward the end, you can clearly see that the two pulleys are completely different (the shiny silver one at the top is the one i bought), and i think even the washer that goes on the outside of the tensioner pulley is different than before (it's deeper than the other one), and i don't think it would fit properly if i changed it back out with another one like the top one.

i'm gonna be ******* PISSED if i find out the shop did a "switcheroo" with the tensioner on me while they had my engine out.....

can someone try moving the tensioner on their (assuming it the stock one) and see if it moves as much as this one does?

 

This may be partly due to spraying the pulleys with WD-40. Its a penetrating oil and will dissolve greases. Its not good for any lubricating application on a car either. It lasts less than the proper greases/oils and you can end up worse off.

A mechanic's stereoscope will help you find the squeal.

If you take your wrench and help the tensioner by adding tension, that should confirm if the tensioner is an issue in your situation, or not.

 

yeah, i know WD-40 is not a permanent solution, it was just a diagnostic tool, because i had it and not a steth, and i was planning on packing the bearings with grease anyway...i just wanted to find out which one(s) were causing the sound.

i tried adding tension with the wrench (making the belt tighter/taut), but it did not help. what helped was when i moved the tensioner front to back (reducing twist on the belt), instead of side to side.

i've already got a new tensioner assembly ordered to replace the squeaking one, hopefully that will fix it once and for all (after the new pulley on the new tensioner is re-packed with grease).

 

no need...none (or very, very little) of it got on the belts. i used the straw to get it right into the area where the bearing spins and just barely sprayed any of it on there, just enough to get down into the bearing, but without slinging a whole bunch of excess all over everywhere. if any of it got on the belts, it's just a very fine misting of it, no solid droplets, due in part to the very little that i used to begin with, and partly due to the radiator fans blowing most of the excess away.

 

You could also have a bad pulley.

 

i addressed that in the first post...top of the two is brand new & has been re-packed with grease....bottom one is not the same brand new one that i put on there just before taking it to this shop, but will be replaced with the new tensioner anyway, and will be opened up & packed with grease prior to installation.

 

I meant the physical pulley. (not the pulley bearings). If a belt groove is bent, chipped, etc., you can get some belt squeal.

 

Looks like too much wobble to me. Enough that the tension could push it out of alignment causing it to make noise, and you putting the wrench on there to push it back seems to validate the theory.

 

Yea, but the tensioner doesn't have ribs. The belt should be able to float freely on the pulley, even if it moves.

I'd be more curious to know if the marks on the tensioner are showing that it is keeping the proper tension.

 

Right but he said the squeak isn't coming from the belt itself. When he pushes it back to alignment the pulley stops making noise, making me think the odd pressure on the bearing is what is making the racket. I believe a new tensioner always comes with a new pulley anyway, so replacing the tensioner would both regain proper alignment and get a new pulley/bearing in place.

 

The OP said that they re-greased the pulleys, so I'm assuming they are not the source of the noise. The correct tool (stethoscope) could confirm that instantly. In that location, the OP could also use a metal rod and hold it up to their ear to confirm if the noise is coming from that assembly.

 

i guess we'll find out soon enough, though...i wasn't happy with the amount of play in the tensioner anyway, and i definitely don't like that the tensioner pulley that's on there now is different than the one i originally put on it....i don't even know what brand pulley it is atm, just know that it's some cheap-*** chinese POS. the ones i put on there were much better quality, made in Canada. after replacing the tensioner assembly, i'll kill 2 (or more) birds with one stone...

1) less slop/play in the tensioner
2) known make of the tensioner/pulley (AC Delco) to make replacing much easier
3) no more squeak (hopefully)

i may not get around to it until this weekend, since my world at work for the next couple weeks is about to kick into high gear, but i'll post back with results, and maybe a video of it being fixed, and the difference in the amount of play in the tensioner, new vs old

 

well it was definitely the tensioner....got it all swapped out and no more squeak, and there's much less play in the new one than the old one. haven't had a chance yet to get a video, and i'll probably wait at this point until it starts cooling off....i've had enough of this ******* TX summer heat....