Damaged Cooling Fan

[earossi]

Upon inspection I discovered that there is a small piece of metal missing off the trailing edge of one of blades on my 11 blade fan. Not sure how the damage occurred; but, I may have caused it when disassembling the alternator from the fan housing. I was able to clean up the broken area with a Dremel tool and have feathered out the break area so that there are no sharp corners that could act as stress risers. The damage is confined to about mid-span of the blade, on the trailing edge of the blade. And, the size of the dressed up area is about the size of half of a dime (i.e. a semi-circle that is about a half inch in diameter),

My question is whether the fan can be put back into service? And, is the balance of these fans sensitive to this loss of metal out of one blade? So, should I counter that by removing some material 180 degrees from the damaged blade? The car is a street car and the engine will seldom be revved to red line (~ 7000 rpm).

The fan, I believe, is aluminum and is fitted to an 87 3.2 motor.

[safe]

Its a damage common for when you try to hold the fan with a screw driver instead of the proper tool when removing the nut.
If its not to big I wouldn't worry and just use it. All 911 fans are magnesium until the 3.6.

[911pcars]

The fan/alternator rotates faster than engine speed due to the pulley ratios.

If the fan is missing a chunk, it's out of balance. How much? Only way to tell is to have it balanced. Using it as is risks further damage and/or excess wear to the alternator bearings. I wouldn't suggest best-guess DIY balancing, but YMMV.

Sherwood

[E Sully]

Fan is most likely magnesium if original. Special equipment is needed due to potential for magnesium to catch fire and burn uncontrolably. If you wanted to have it tig welded up and ballanced it can be done by the right shop. Good used or aftermarket aluminum are also avaiable.

[safe]

Fans are expensive, alternator bearings are cheep.

[47silver]

Welding Magnesium Video

[gumba]

Any shop recommendation for this type of repair?

[47silver]

i would guess it would require 2 hours of time to fix your fan, that is at least 200 dollars.
so you may be better off to post on here for another fan in the classifieds.