I am an embarrassment to this forum and all its fine patrons and apologize for wasting your time!!
First off, I have both belts. Old and new. The old one has been on the car three years. I couldn't get either one re-installed yesterday. I HAD gottten one of them on on Monday though. No idea how i did that. anyway, both have the same part number and came from FCP. The old one has stretched about maybe 1/2 inch. Not as much as I previously estimated.
As I often do with something like this, i take everything apart and put it back together. I drained the PS Fluid, coolant, removed the radiator, removed the t-stat, removed the idler and tensioner.
All looked good, until it was revealed to me that when SOMEONE installed the alternator (me), the lower mount (with the interference fit and the bushing) was not bolted to the Oil Filter housing. It was just resting on top with the bolt tightened through the little bushing in the back.
in other words, when I loosened the upper alternator bolt a hair, i could swing the alternator up and down.
I am here humbly to admit my mistake and let everyone know that when you are buttoning up a head gasket install, many hours into the day, you should probably slow down your pace with the IPAs, less'n you make a bonehead mistake like that which (if the belt slipped off or broke...still shocked i got it installed at all) could ruin a number of accessories by having too much tension, not to mention kill your water pump etc.
Thanks for all your input and help though. I just have to laugh at how ridiculous this is, but i suppose stuff happens!
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2005 X5 3.0i - 71k mi (9.2018) -> 81k (9.2019) -> 100k (9.2021) -> 123k (8.2025)
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SOLD : 2003 X5 3.0 - 177k mi (9.2018) -> 186k (9.2019) -> 205k (9.2021)
SOLD : 1997 328is Coupe - Hellrot Red
SOLD : 1988 528e w/ Bullseye s256 / MS2 Extra / GC Coilovers / Yukon Coils ~ 300+ HP