Has anybody seen the engine fan do this?

[JFairman]

The engine fan in my '87 911 turbo seems to be corroding, swelling, and cracking from below the surface where balancing holes were drilled in the back side.
Guess I better keep it below 5000 rpm and look for a good used fan before this one explodes and ruins the fan housing or more.

Here's a few pics.
The swelling and cracking is at 12 o clock and swelling without cracks yet over by 9 o clock.
Does anybody have or know of a good used one they want to sell?

thanks,
Jim

[jhg41977]

I wouldn't run that fan.

[itsme]

+1, find a fan, that thing is not safe to use.

[afterburn 549]

I am thinking there are just so many turns, just so many hours even in a great aluminum part be for failure occurs

[E Sully]

Fan is magnesium, and it seems to have bad oxidation.

[Steve@Rennsport]

Magnesium is VERY prone to corrosion and must be protected, especially in a salt-water climate. It appears that the backside didn't get coated properly as these failures are not common on these fans.

[wachuko]

Yes... it happens. I had to replace mine due to the same issue. Not uncommon.

[wachuko]

In my case both the housing and the fan had cracks...

[JFairman]

Thanks for posting everyone...

Wachuko, I see you're in the land of humidity too.. Florida
Maybe that has something to do with this and like Steve said mine probably didn't have a good protective coating on the back side to keep the humidity from eating the magnesium inside the balancing holes drilled in the back.
If I ever have another magnesium fan I'll clean the back side up real good, maybe even bead blast it to clean it and then spray a couple coats of clear engine enamel on the back inside to seal it.

Did you find a good used magnesium fan and housing or go with the only new fans I've seen available now - the cast aluminum ones like you see on ebay?

In the thick folder of repair shop work order receipts that came with my car I see the previous owner replaced the magnesium fan housing because it was cracked. It's in real good shape and I keep some marine grade corrosionx on it to keep it looking nice.

[wachuko]

At the time I could not find a replacement in good condition... everything I found had cracks...

Ended up having to replace housing, fan, and alternator (because the old one did not fit the new fan/housing combo). Replacements were aftermarket made out of aluminum.



Link to the thread:

90amp alternator wiring???

[JFairman]

Looks good.
I wanted to put the original fan strap allen bolt at 3 o clock like you have yours but then a vertical AC compressor bracket that attaches to the top chain case stud with a special shoulder nut (you can see it in your pic) was in the way so I positioned it at 2 o clock.

The original 11 o clock location of it was too close for comfort to the bottom of my Kokeln intercooler core.

[911pcars]

FWIW, thick finishes like powder coating can mask surface cracks in critical parts. This is especially important as it applies to wheels and other suspension parts.

Sherwood

[wachuko]

Originally Posted by 911pcars

FWIW, thick finishes like powder coating can mask surface cracks in critical parts. This is especially important as it applies to wheels and other suspension parts.

Sherwood

I used tractor paint

[wachuko]

Originally Posted by JFairman

Looks good.
I wanted to put the original fan strap allen bolt at 3 o clock like you have yours but then a vertical AC compressor bracket that attaches to the top chain case stud with a special shoulder nut (you can see it in your pic) was in the way so I positioned it at 2 o clock.

The original 11 o clock location of it was too close for comfort to the bottom of my Kokeln intercooler core.

Turbo... space is limited...

Just sharing what I did. Others sure to chime in.

[JFairman]

I just ordered a new fan from the place in Miami that starts with a V. He said I should have it tomorrow since I'm just 90 miles up the road from them.

The guy on the phone said these cast aluminum fans they sell are made in Europe, not Asia.

[wachuko]

Originally Posted by JFairman

I just ordered a new fan from the place in Miami that starts with a V. He said I should have it tomorrow since I'm just 90 miles up the road from them.

The guy on the phone said these cast aluminum fans they sell are made in Europe, not Asia.

I got it from the same place... just be aware of the issue I had with the fitment of the alternator, ended up having to upgrade that as well... I hope that is not your case. Keep us posted.

[JFairman]

The guy I talked to asked me what model 911 it's going in to so it should be OK. He has a good sense of humor, had me laughing.. didn't get his name though.
My car comes with the 90 amp alternator and I think it's the biggest one.

The UPS tracking number just showed up in my email program while I'm writing this... say's it'll be here tomorrow.
most excellent!

[wachuko]

90 amp? Yeah, you are good to go then.

Work travel sometimes takes me to Miami for meetings. I have been to their old place and the new store. Nice guys all of them. Gear heads to the core.

I do most of my P purchases with Pelican, Sunset Porsche in Oregon (yeah, sometimes buying from Porsche is less expensive) as they have the largest selection at decent prices. With the 912 I learned about Sierra Madre Collection... larger supply for 912 parts than our host. So between the three of them they take all my credit card allocation