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I'm tracking down an external engine noise on my '02 V6. I think it's a bad bearing in one of the idler pulleys for the serpentine belt. It's #1 in this image, the upper pulley on the US passenger's side, above the alternator:
The pulley in question is not to be confused with idler pullery #3, which is closer to the centerline.
The naughty pulley #1 measures about 5.375" diameter. Searching online, lots of search results give me pulley #3 instead, which is maybe 3" diameter or so. Both are grooved for the drive belt. Some searches even show me pulley #5, which has no grooves and is part of the tensioner assembly. As you might imagine, this is getting very frustrating try to find the correct one.
Here's the rub. When I think I've found the correct one, it is over $100! Yikes, my Scottsman's wallet is crying in pain. Actually, all I'd like to do is replace the bearing itself. It looks to be a press fit inside the pulley. I won't be able to tackle this project until next week, but would like to minimize downtime by pre-ordering the bearing. Anybody have any idea what it might be?
Still waiting on some free time to tackle this and other projects on the car. I'm just a husband. I don't get to decide how my time is spent. Hopefully Tuesday or Wednesday...
Wow, I was less correct than usual about the source of the noise. I finally had some free time to work on the car. Fortunately, I was able to duplicate the noise and it turns out it's coming from under the car, not the idler pulley like it had previously seemed. The noise has also gotten louder, and it's more of a rattling noise. It's really bizarre how tricky it can be to track down the source of a noise.
It's worse when cold, and is somewhat RPM dependent. Just above idle is worse. Give it more gas, and it quiets down immediately. The noise seems to be related to exhaust flow. My best guess was a cat failure, with broken core pieces rattling around downstream. I should also mention about a week ago I started getting a P0420 code (#1 cat efficiency) on every trip. This cat has already used up 8 of its 9 lives, as I had a severe misfire (oil leak in spark plug well) several years that nearly killed it. I'd been nursing it along all this time, as the code was very intermittent, maybe only once or twice per month. Oh well, it appears this cat finally let go internally.
I took the car to a muffler shop and they confirmed the failure. They pulled the downstream O2 sensor and scoped the inside. The downstream matrix was missing. Pieces of that must be what are making the noise back in the muffler. I'm waiting on a quote from the shop to replace it. I've looked at some aftermarket units that look to be a direct fit, but I'm old and cranky and would prefer to pay the man versus wrestling underneath the car for who knows how long. Even though I own practically every tool known to man, I do not have a lift and this would be a miserable job with the car up on jackstands.
Long story short, it looks like I don't need to replace that idler pulley bearing. The kicker is I've also got some major work I need to do on my pickup, but I need to hold off on that until I can get the car back.
Why don't you just change the bearing anyway so that we know the number?
Norri,
You really want me to get permission from the "Minister for Everything", and pull HER car apart to get you the number???????. Maaaate, you are braver than me.
Wait till she takes a nap, and I will sneak out and do the deed, BUT, she will know, they always do.