Broken A/C Belt issues, Size discrepancy?

[Rickybobby]

First off, let me say that I love my 89 325iX. The wife drove it yesterday, and mentioned the oil light on. This morning I went to top off the fluids and noticed only about a 6" chunk of A/C Belt left. The rest is gone forever, somewhere. Who knows how long I've been driving without it, but the car is just so amazing that I never even noticed, or heard it snap. If anything, I probably have a few more HP now. :)

The belts are real fresh, replaced with a ContiTech 13x810mm about 4 months ago, so there's no reason it should have spontaneously combusted. My questions is this: I see a few different variable sizes on A/C Belts, from 810mm - 825mm. Is it possible I used the wrong size? Also, the drive pulley where the fan mounts does look dangerously close to the crank pulley below it, but no scuff marks that I could see.

Any help is greatly appreciated!

[turbo55]

The rest of the belt is probably on the side of a highway somewhere.
I would think that the 810 mm to 825 mm range wouldn't matter too much since that tensioner bracket thing (pic below) has quite a bit of room on it to adjust the tension (unless the 810 mm already maxes it out). Assuming that with an 825 mm belt you have the gear nut going pretty much all the way to the right, maybe an 810 mm belt you'd have the gear nut somewhere in the middle.
Maybe when you did the belt 4 months ago you overtightened it? I think the Bentley manual says something special about tensioning the A/C belt, it's tensioned differently from the PS pump and fan.

[Rickybobby]

The rest of the belt is probably on the side of a highway somewhere.
I would think that the 810 mm to 825 mm range wouldn't matter too much since that tensioner bracket thing (pic below) has quite a bit of room on it to adjust the tension (unless the 810 mm already maxes it out). Assuming that with an 825 mm belt you have the gear nut going pretty much all the way to the right, maybe an 810 mm belt you'd have the gear nut somewhere in the middle.
Maybe when you did the belt 4 months ago you overtightened it? I think the Bentley manual says something special about tensioning the A/C belt, it's tensioned differently from the PS pump and fan.

OK, I'm definitely on the right track - now I have a belt gauge but I can't find the proper belt tensions for the life of me! Anyone have them handy?