jimq

Wow I think I will check mine!

cobalt

+1

Although IMO that fan was damaged a while ago and it has gotten worse over time due to high speed rotation of the fan. It is highly unlikely that this type of crack started by itself. Although you have considerable corrosion on the fan and accompanying housing what most likely happened here is someone used a pry bar or long screwdriver to hold the fan in place while tightening or loosening the nut for the fan belt pulley cracking the casting where the blade and housing come together.

EDIT: As I look at it again I would say it is specifically related to removing the nut the bar was placed through the blades above the cracked area and as they tried to remove the nut they put to much force on the blade pushing it away and causing the crack. You might find the area behind the blade is cracked also.

Your only option is to replace the fan with a new one. I would paint the housing while your at it.

AOW162435

Mike,
I would replace the fan. Having that thing come apart at speed will not be pretty. If you are replacing it with new, make sure your fan bearing is sound, otherwise you risk the new fan blades making contact with the housing. This can cause cracks, but also, will abrade the factory coating from the fan blade tips allowing the magnesium to begin corroding.

When I replaced my alternator last winter, I thoroughly cleaned & degreased the fan before priming, painting & clear-coating with hi-temp paints. To date, it still looks fantastic. I did the same to the magnesium fan housing. For the housing, I used DupliColor primer and 'Cast Iron' high temp. For the fan, I used DupliColor primer, 'Aluminum' and Clear, both in high temp as well.











Andreas

cobalt

Damn that looks better than new

You will find that small debris gets sucked in by the fan, no matter what you do the edges will chip. The factory used Zermatt Silver paint on these which turns a goldish color over time. best thing to do is touch up the chips as they happen.

SNOWBIRD

AOW, your fan looks awesome! I was going to paint mine, when the shop owner looked at me like I had two heads I changed my mind. He expects to get the fan Monday/Tuesday... 2.5 Hours labor and slide the MasterCard.......
I have some lose screws on my boats console to tend to, lose muffler on the Harley and some bling to install... So, I'll leave this to the shop that discovered it to fix, they probably saved me a couple grand.

Thanks for the help guys.

jimq

maybe a canadian goose flew into the fan

Strega(UK)

I run the turbo style fan on my C4 as it came with an uprated alternator I bought, I have never had any problems with it whatsoever. If they are that much cheaper maybe you should go for one of those.

AOW162435

Mike,
I received a failed fan in the mail today from another Rennlister. I've never seen a worse case of magnesium cancer than this:











Andreas

SNOWBIRD

Mine is gonna make you a prettier clocok!

AOW162435

I look forward to receiving it. Thank you again.


Andreas

cobalt

Very interesting. Although that does not appear to be magnesium corrosion.

Hard to tell but I would say we have another case of either someone damaging the fan or something being sucked into the fan and causing the damage. The black appears to be carbon or oil residue of some type. Either the fan was cracked and it got worse over time from the high speed forces while spinning or it shattered on impact and has been like that for a while. Magnesium corrosion is never black like that. It is usually a white or gray powdery substance from the salts.

SNOWBIRD

Now that I've held it in my hands and get a close look at it, the fact that the shaft was so buttered up (from trying the wrong tool) that I already replaced the alternator, and how few have reported failures here..... I concur.... I bet that is exactly what happened..

And, no, I didn't do it

AOW, will mail the old one off shortly, look for a LL Bean box in the mail.

BTW, the new one came already painted silver like cobalt said.

AOW162435

Thank you!


Andreas