koda2000
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So last weekend I was standing outside when my daughter fired up her '00 Mountaineer 5.0L. I heard the unmistakable sound of a bad bearing coming from the left front of the motor. I went and got my mechanics stethoscope and placed it on the alternator and heard a loud noise. Checked everything else I could get to easiy, but the noise was loudest on/around the alternator.
The alternator was a reman from AutoZone with a lifetime warranty. I'm guessing I installed it around 5 years ago. Called AZ and they had one in stock, so I went and got it, installed it but I still had the bearing noise. I had replaced the tensioner w/pulley about 4 years ago so I was thinking that the tensioner pulley probably was not be the issue and on the stethoscope test didn't sound noisy. So that left the small plastic idler pulley, I didn't bother to listen to it directly (didn't feel like jacking the car up and crawling around under it).
So I deduced that the small pulley (or maybe the tensioner pulley) must be at fault. I ordered both from RA (Gates brand) for around $23 delivered and received them yesterday afternoon. I replaced both pulleys last night, but I didn't get the belt back on until this morning. All's good now, nice and quite. The small plastic pulley didn't sound terrible when spinning it by hand, but it was very dry and I'd never replaced it before (now has over 265K on it as far as I know). Now I have a spare serviceable tensioner/large idler pulley, which never hurts to have. I'll add it to the spare serpentine belt I have.
So, how come the bearing noise was so loud at the alternator? I think this was because all three pulleys are mounted on the same one-piece aluminum bracket and the bad bearing noise was transferred/amplified by the bracket. Next time I'll take the time to test each pulley individually and avoid the anxiety. Not a day goes by you shouldn't learn something new.
The alternator was a reman from AutoZone with a lifetime warranty. I'm guessing I installed it around 5 years ago. Called AZ and they had one in stock, so I went and got it, installed it but I still had the bearing noise. I had replaced the tensioner w/pulley about 4 years ago so I was thinking that the tensioner pulley probably was not be the issue and on the stethoscope test didn't sound noisy. So that left the small plastic idler pulley, I didn't bother to listen to it directly (didn't feel like jacking the car up and crawling around under it).
So I deduced that the small pulley (or maybe the tensioner pulley) must be at fault. I ordered both from RA (Gates brand) for around $23 delivered and received them yesterday afternoon. I replaced both pulleys last night, but I didn't get the belt back on until this morning. All's good now, nice and quite. The small plastic pulley didn't sound terrible when spinning it by hand, but it was very dry and I'd never replaced it before (now has over 265K on it as far as I know). Now I have a spare serviceable tensioner/large idler pulley, which never hurts to have. I'll add it to the spare serpentine belt I have.
So, how come the bearing noise was so loud at the alternator? I think this was because all three pulleys are mounted on the same one-piece aluminum bracket and the bad bearing noise was transferred/amplified by the bracket. Next time I'll take the time to test each pulley individually and avoid the anxiety. Not a day goes by you shouldn't learn something new.
