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Re: Going thru alternator belts???
These days it is hard to find anyone who understands that V-belts come in different profiles, not just different sizes. So once you confirm that you've got the right profile, and size, you also need the right length. Usually if the belt number is something like XYZ36 that part of the belt number would indicate it is 36" long, and (duh!) the XYZ35 is then one inch shorter. XYZ34 is two inches shorter. Finding any v-belt at all in stock anywhere, not so easy.
And if someone at some time had the alternator repaired or replaced, and used a different pulley size? The stock belt length could be wrong now. Best bet is to take a good piece of string, wrap it around, measure it. If it seems like the belt you have is an inch too long, compare that to what the string measures. In the worst case you try two new belts, one an inch shorter, the other two inches shorter. Half-inch increments would be nice but at least get in the ballpark.
You may also be able to find a belt tension gauge and a belt tensioner/spreader to make the job easier. The gauge actually tells you how much tension is on the belt (hard to find these days, but they exist!) while the spreader is a turnbuckle-type gizmo that fits between the two pulleys and forces them apart, so you can tighten the alternator down in a leisurely manner while the tension is being held by the spreader.