'97 Taurus GL 3.0L: Alternator Bearing?

'97 Taurus GL 3.0L: Alternator Bearing?

It’s a hollow, dry-sounding noise that seems to be coming from the alternator pulley as it rotates. Just started a couple of days ago, doesn’t seem to be getting any worse, but I’m concerned that if it IS the bearing, maybe it could seize up and burn the serpentine belt? Is this what will happen?

In the meantime, can I spray something into the pulley area to help with lubrication, or is that worthless? I know I’ll probably need to replace the entire unit (can’t just fix the bearing, can you?), but I don’t know when I’ll get to it.

If you remove the serpentine belt, and then rotate all the pulley’s slowly by hand, you can pretty much feel what bearing is going out in which component.


Can you fix a bearing and save the alternator? Seems like a waste to throw away a working alternator just because a bearing is no good.

Yes, you can disassemble an alternator and replace the bearings only. You’ll have to remove them and have them matched up by the numbers. Many auto parts stores carry a selection of bearings and these can also be gotten at a bearing supply house or an electric motor repair shop.

It’s the idler pulley, not the alternator that’s bad. Just pulled out of the driveway (about 5 feet) to a sudden burning rubber smell, and as I proceeded to pop the hood to investigate, billowing white smoke starting pouring out. After cutting away the distorted serpentine belt, all the pulleys turned by hand except the idler pulley (just below the alternator pulley). Repeated twisting back and forth finally got it to move, but it’s definitely the source of the noise I was hearing. It’s sounds like it’s all corroded inside there.

4 questions:

1.) Is this going to be a big deal to fix? Does it simply bolt to the engine block?

2.) The (other) tensioner pulley appears to have remnants of the serpentine belt stuck to it all the way around its circumference for half its 1" width. Do I need to clean that off? Should I clean the other pulleys also (grooved ones might be difficult). What’s the recommended cleaner?

3.) I’ve got a replacement serpentine belt that I bought probably two years ago, but never installed it. It’s been sitting inside the house on a bookcase away from any heat sources. Is there any risk of dry rot with this belt?

4.) Any chance anything else got damaged when the serpentine belt burned up? I stopped the car immediately upon seeing the white smoke.

Nothing’s easy. Ended up visiting 6 places looking for this stupid pulley (or a replacement bearing). AutoZone and Advance couldn’t get the bearing and only had (thinner, sharp edged) plastic replacements ($~15), which I refused to install. Then, both dealers were out of stock until the following week (would’ve been $23 - not bad) and wouldn’t sell me just the bearing. Finally, NAPA pulled a metal replacement out of their hat for $19 - and it was almost exactly the same thickness, but it still bothered me that I couldn’t just replace the bearing. I had just read an article in my Popular Mechanics issue about recycling and how we throw away so many durable goods, so I pressed onward in search of the bearing. Finally found one at a Car Quest garage on a Saturday (a rare feat in these parts) - and they even pressed it in for me ($6). Returned the NAPA part only to be told they had the bearing (that I know I asked for) for $4.

Installing it wasn’t a big deal - just a single bolt, but I couldn’t get the wheel to spin as freely as the tensioner pulley for some reason. I hope this doesn’t become a problem over time. It turns OK, just won’t free-spin. I’m pretty sure I put all the old washers back on the same way they came off: the thicker blackened washer right behind the bolt head, and the thinner (cupped or tray-ed) washers dropped into the grooves on either side of the bearing such that they fit flush. Finallly, the “holding” washer with the “fingers” and slots turned onto the bolt threads on the backside to hold it all together. Maybe as it turns it’ll loosen up?? Seems to be working OK so far. Belt doesn’t appear to be “walking” at all. First time I’ve ever changed a Serpentine belt on any of my cars (this one lasted 150k miles, by the way - and would’ve gone longer if not for the failed pulley). Not much room slipping the belt in on this car: only about 1/2 inch between the closest pulley bolthead and the fender. You have to twist the belt edgewise and slip it down underneath the bottommost pulley - which I didn’t do initially resulting in the belt getting stuck in there widthwise. Then, you really cannot verify how it wraps around the bottommost pulley (A/C?) without removing the splash shield - but I was able to slip my hand up underneath and feel around for the rails of the pulley and the belt in between…

I pulled the degas bottle to give access to the bolthead. Otherwise, it wasn’t coming out without buying some “low-profile” socket or serp belt tool. The residual belt material wrapped around the tensioner pulley ended up cracking and falling off in one or two large pieces. This was another reason why I pulled the degas bottle: I thought I was going to have to sand the pulley’s surface to wipe away the belt residue as I had to do with the idler pulley. On re-install, for the tensioner pulley I had to use a short box wrench because there’s really no clearance there between the bolthead and fender. This is a little tough because of the spring tension on the tensioner - you’d certainly like a longer bar for more leverage, but it’s doable…

Welcome to the art of auto repair. Usually you can find replacement bearings at a Bearing Store. Look around light industrial or machine shop areas. The reason the new idler does not turn as well as the used one is that the new bearing is fully loaded with grease. But if it is quiet, running smoothly, not getting hot, you are good to go. You might keep an eye on the other idler to see if it is running hot or just replace it prophylactically.

Thank you for your description of your repair ordeal. Sometimes hearing how someone else solved difficulties gives us points for future suggestions.

Well, I know my posts can tend to get lengthy, but I do that because I know I’ve searched for automotive solutions on the Web myself only to find posts with incomplete descriptions that left me wondering what the poster was talking about. So I put a lot of detail in to try to eliminate any possible gaps. My apologies to the professionals out there …