cold weather cause alternator bearing failure?

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Oct 28, 2024
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Van in my signature turns 20 this year. With the recent cold snap (-15c) it's been all well except the alternator, as it's making a disgusting grinding noise. I assume it's OE Denso based on just how it looks but i got the van with 187k on it so service history on anything except oil changes is pretty much unknown. as i ask in the title, is it possible the cold weather froze the grease in the bearings causing the failure? I've already ordered a reman 160 amp from BBB Industries off rockauto but the mode of failure is what im wondering
 
Van in my signature turns 20 this year. With the recent cold snap (-15c) it's been all well except the alternator, as it's making a disgusting grinding noise. I assume it's OE Denso based on just how it looks but i got the van with 187k on it so service history on anything except oil changes is pretty much unknown. as i ask in the title, is it possible the cold weather froze the grease in the bearings causing the failure? I've already ordered a reman 160 amp from BBB Industries off rockauto but the mode of failure is what im wondering
I'd open it up and replace the bearings and keep OEM

And sure, bearings can be noisy when stiff and cold and then loosen up. It'll eventually progress to another level of failure, but it's anyone's guess how long that will take

BBB is questionable at best....
 
The alternator on my truck absolutely SCREAMS in the cold. It locked up 2 years ago when I was dumb and left it on the floor for a month and a half while I replaced a head gasket on the truck. I keep forgetting to buy a new alternator for it.

I wouldn't say it's quiet during the warm, either. But I definitely need to replace it.
 
I used to have an 84 Rabbit which would do the same thing during very cold prairie winters.
I always anticipated the alternator failing (because of the noise), but strangely enough it continued to work with no other issues.
 
Ha...cold weather got my alternator ('07 Volvo w/148k) growling; a bearing, I thought.
Upon shutdown, the buzz slowly died down...ergo, bad freewheel pulley.
 
So funny thing about this. Ford recently starting making a newsletter for dealers and this gem was pretty well torn apart by all the techs and parts people.

1738011793020.webp
 
Had a screaming alternator once on a Dodge van. Sprayed WD-40 into it and it stopped. Never did have to replace it. Just dumb luck I guess 🤷‍♂️
 
Mine does when it's well below 0°

But to eliminate any belt squeel, spray some 303 on an old toothbrush and make sure all the grooves are well coated. Then use a rag to wipe off the excess so it doesn't fling everywhere.
 
possibly diodes b/c the headlights/cluster lights pulse on acceleration
Could also be (a) dirty ground(s) or glazed carbon brushes/slip rings. Both issues can be corrected with some scotch-brite, but a quick check of the diodes is to turn as many of your electrical accessories as possible such as high beams, full fan, rear defrost, etc then check the AC (not DC) voltage at the alternator b+ terminal. The acceptable level can vary from vehicle to vehicle but typically 0.5 AC is the limit and more than that is considered to be a bad rectifier/diodes.
 
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