Delcotron 12si Alternator Question

[1987 GMC Jimmy]

I posted a while back about a 2 in 1 noise issue that I was having. A kind of proto-PS pump groan was one of them, and I'm 99% sure the other is my alternator. I was wondering if anyone has had the cooling fan get damaged (maybe warping of the thermoplastic when being torqued on with an impact wrench) on one of these that would cause it and the pulley to wobble around. I'd otherwise suspect the bearing, but there's no noise coming from the alternator, the end of the shaft where the nut is appears to spin true, and it charges just fine. Finally, will a 10si fan (bladed) fit on the 12si (disc) if I decide I need a new fan and can't find one?

 

[1987 GMC Jimmy]

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[Snoots]

will a 10si fan (bladed) fit on the 12si (disc) if I decide I need a new fan and can't find one

Why would you change it? The 12SI fan moves a lot more air than the 10SI. Better cooling, greater longevity.

 

[1987 GMC Jimmy]

Why would you change it? The 12SI fan moves a lot more air than the 10SI. Better cooling, greater longevity.

I've got a spare 10si laying in the shed so just for the free part. I'm sure my local alternator shops have a few fans laying around, but I meant as a last resort. I'd much prefer the better fan.

 

[4WDKC]

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Its possible I have seen remans that had bent fans in the box at the parts store. It shouldn't over torque it unless you have some way to hold the fan while hammering on it with the impact.

 

[hatzie]

The 10SI fan may fit but it won't move enough air to cool the 12SI.
I've seen re-man 12SI units with bent/warped fans.

 

[Snoots]

You shouldn't have to hold the fan. The nose of the alternator shaft is fitted for an Allen key.