Serpentine belt tensioner
On my 2002 V70 X/C, I just replaced the timing belt for the first time at about 105k miles. (as well as timing belt tensioner & idler. I'll do the water pump the next time around). Pretty simple job really. I removed the crank pully as it just made the job a bit easier, although I did use the crankshaft pulley holder (
), which made removal a cinch, provided you're used to using a 4 ft cheater bar on the crankshaft pulley nut. If I'd had a better 1/2" impact (my older IR231 just isn't up for the task apparently), I probably could've removed it, but I got the holder primarily because I like to torque things during re-assembly.
I got it all back together and started it up, and had bearing noise at about 1100 RPM. Removed the serpentine belt and the noise went away. I spun the serpentine belt tensioner pulley by hand and it free-wheeled a good 30+ times before slowing to a stop - that tells me it's a bad tensioner bearing.
I have a new tensioner on order and expect it to resolve the issue. In the meantime, I thought I'd press out the bearing on the old tensioner. After all, if I could replace the bearing, I may be able to re-use the tensioner at a later date if need be (I know, the tensioning spring wears out too). Anyway, for anyone who's interested - not going to work. The bearing's OD is ribbed, and is apparently installed into the plastic pulley while hot during manufacture. For those who're interested, here's what it looks like - I broke the plastic pulley wheel trying to press it out (not a big deal since I have a replacement coming):

I got it all back together and started it up, and had bearing noise at about 1100 RPM. Removed the serpentine belt and the noise went away. I spun the serpentine belt tensioner pulley by hand and it free-wheeled a good 30+ times before slowing to a stop - that tells me it's a bad tensioner bearing.
I have a new tensioner on order and expect it to resolve the issue. In the meantime, I thought I'd press out the bearing on the old tensioner. After all, if I could replace the bearing, I may be able to re-use the tensioner at a later date if need be (I know, the tensioning spring wears out too). Anyway, for anyone who's interested - not going to work. The bearing's OD is ribbed, and is apparently installed into the plastic pulley while hot during manufacture. For those who're interested, here's what it looks like - I broke the plastic pulley wheel trying to press it out (not a big deal since I have a replacement coming):

Interesting. I'd be curious on brands of tensioners. Mine was replaced ~70K miles. I believe it is aftermarket and the tension spring must not be up to spec. At exactly 1,450 RPM I get a very annoying buzzing where the belt vibrates like a rubber band.
The suppliers have a few brands at all different prices. Or maybe it's the belt itself.
Bob
The suppliers have a few brands at all different prices. Or maybe it's the belt itself.
Bob
Rats. I replaced the serpentine belt and tensioner, and the sound remains. The only other items driven by that belt are A/C compressor, alternator, and power steering. I'm guessing either alternator or PS pump, but can't tell for certain. It has a sound very similar to
, but it happens right around 900-11000 RPM only, which is just slightly off idle.
I listened to the sound when the A/C compressor cycles on and off, and it doesn't change. It also doesn't change when I turn the steering wheel, or turn the headlights on or off, so I'm a bit stumped. I may have to wait for it to get a bit worse before I can diagnose it for sure. Right now it's only mildly annoying - the car runs and drives just fine. I can't even be certain that the noise WASN'T there before doing the t-belt. The only thing that's certain is that the noise goes away when I disconnect the serpentine belt.
I listened to the sound when the A/C compressor cycles on and off, and it doesn't change. It also doesn't change when I turn the steering wheel, or turn the headlights on or off, so I'm a bit stumped. I may have to wait for it to get a bit worse before I can diagnose it for sure. Right now it's only mildly annoying - the car runs and drives just fine. I can't even be certain that the noise WASN'T there before doing the t-belt. The only thing that's certain is that the noise goes away when I disconnect the serpentine belt.
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shahidocean
Volvo V70
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Sep 14, 2010 06:45 PM




