'97 Taurus GL 3.0L 163k: Pinpointing Pulley/Belt Squeal/Chirp

[Colt Hero]

'97 Taurus GL 3.0L 163k: Pinpointing Pulley/Belt Squeal/Chirp

Almost a year to the day I replaced the bearing on my idler pulley (along with the serpentine belt because it had gotten burned up when the bearing seized), I've got a squeal/chirp noise again. It's most audible at idle up to about 40-something mph. Above that you can't hear it. I tried listening at idle to see if I could pinpoint the source, but I couldn't. Is there a way to do this? Should I try spraying each pulley with lubricant one by one until the noise subsides? It'd be nice if I could systematically re-arrange the Serpentine Belt to take one pulley out of the loop at a time. That would certainly work.

The concern I have right now is if it's a bearing again (idler pulley or alternator, etc.), it could seize up and destroy my newish belt again (and I'd be stranded somewhere, right?). Of course, the other question is if it IS the idler bearing again, why did it fail after only one year???

[shorod]

You could go the route of using brake cleaner and systematically spraying each pulley. The brake cleaner evaporates quickly but provides ever so slight amounts of "lubrication" so you will know when you find the right source of the chip. It could also be the belt, so if it seems to go away momentarily with any pulley that you spray, you probably have a noisy belt.

-Rod

[brcidd]

For chirping belts- you can rotate the belt 180 degrees- let it run around the other direction- this will usually quiet them down - makes for an interesting test- I've done it a few times when no time to goi get a new belt- Just take it off, turn it around and re-install it- see what happens...

[shorod]

Interesting, I'll have to make a mental note of this. Thanks for the tip.

-Rod

[Colt Hero]

brcidd:

Hmmm, that's interesting. Didn't think of that one. I guess I'll give that a try since I'll be pulling the belt off anyway. I'm thinking, though, that it's going to be the idler pulley again. The belt is only a year old and still appears pristine. I guess there could be a tension problem, though

shorod:

Doesn't brake cleaner dissolve grease? You know, speaking of grease, when I installed this new idler pulley bearing last year, it really never occurred to me that I might have to grease it in any way. Should I have? It looked to be a sealed ring, but maybe I should have pressed a wad of grease into either side of it anyway? The other thing that DID occur to me at the time is when I handed the bearing to the guy in the machine shop to press it into the pulley he made me cringe when he let the head of the press push the bearing in too near the center. I was thinking he should've put a large socket or piece of pipe in between to make sure the pressure was applied to the outer ring. What do you think the chances are that this bearing might've been damaged from Day 1 - and this is why it never really spun freely once it was bolted on?

[brcidd]

Surest way to brinell a bearing is to press it in with the pressure NOT on the outer race-- I would have thought a replacement tensioner pulley would have a new bearing in it already- no need to press one in- unless you opted to just try and change the bearing- a whole lot easier just to buy the assembly IMO....

[Colt Hero]

brcidd:

It might've been easier to buy a new pulley, but the replacements I found were inferior to the original, so I went with the new bearing. All but one of the replacements were plastic (which I refused to use), and the one metal one I DID find (Napa) was narrower than the original (which I wasn't comfortable with). Plus, the bearing cost me less than $5 as opposed to the replacement pulleys which ran about $16-$20.

The funny thing was I had actually bought the Napa metal pulley and was just about to install it when the landlord's handyman dropped by to look at the heating system. He was the one who popped out the bearing and told me to buy the replacement for $2 (he said). Before that, I hadn't even considered that as an option...

[shorod]

With the pulleys all rotating, even at engine idle speed, the brake cleaner will evaporate before it dissolves any lubricant. You suggested spraying a lubricant on the belt. You don't want the belt to slip, that would defeat the purpose. Plus, some spray lubricants have the potential to harm the rubber of the belt.

I'm not sure I'd be concerned about a plastic idler pulley being inferior. At this rate, it may have lasted 4 or more times longer than the replacement bearings. There really shouldn't be that much force on the idler if the tensioner is working properly. I suspect the plastic idler would have a bit of dampening qualities to it too which may help reduce noise.

-Rod

[Colt Hero]

shorod:

I wasn't going to spray the belt, I was thinking I'd spray into the center of the pulley where its axle (or bearing) is.

The main concern with the plastic bearing was the thinner surface area for the belt and the sharp edges on it. I just think the smooth, rounded metal edge is better if the belt happens to walk a bit.

Trying to make it to the weekend. Can't do anything during the week with the early darkness. Hope it doesn't fail before then...

[shorod]

I think if you spray the bearings, especially sealed bearings, as soon as you start the engine up it will sling the lubricant enough where it will get on the belt. However, in that situation it probably would not be enough to cause a problem.

-Rod

[Colt Hero]

shorod,

You're probably right about that ...

[Willyum]

Are you sure it's a belt or pulley? You didn't say what engine you have but Vulcan engines have been known to "chirp" from the cam positioning sensor driver.

[Colt Hero]

Willyum,

I HAVE heard that chirp noise from the CMP synchro (about a year or so ago) - about 2-3 years after replacing the synchro and the sensor - but it went away. This noise is definitely not coming from that side of the engine. It's around the serpentine belt.

Bought the AutoZone water pump on Friday ($38), but didn't get to it this weekend. Ended up putting some hours in at work to give me at least three contiguous days this coming weekend in case there are any complications. Besides - the noise has stopped, for some reason. Really weird. I think I'm going to try flushing the system rigorously because the heater core keeps getting plugged up. I blew it out again today (2nd time in two months) so that I'll have some heat tomorrow (and hopefully thru Wednesday). A fair amount of sediment came out. I need to perform that TSB service again with the ph Iron Cleaner stuff to clean out all the gunk in the system. I did this a couple of years ago, but didn't have a formal procedure and maybe it wasn't done quite correctly...