Air cool system FAN housing and Fan replacement

[Juan911]

Hi all I have a 91 964 and to today while driving I heard a huge screeching sound. I turned the engine off right away and when I opened the hood I noticed that the fan was completely against the fan housing. Do anybody know what parts I might have to replace? Do I really need to replace the alternator? I think is the most expensive part so if I don't have to it will be great.

[ValveFloat]

Since no one else has responded, I'll try to help.
The problem could be the alternator, or it could be the fan bearing.
You won't really know what the problem is until you disassemble the pulleys and can isolate the alternator from the fan bearing.
Here are the parts: The fan bearing is in part 28. I was not able to find just the bearing, so I replaced part 28.

There is a good thread here with pictures and video.

[rattlsnak]

hopefully your fan isnt damaged, if so, you have to replace the whole assembly with the updated parts at @ $700.00. Or if your fan isnt damaged, you can also go with an RS style hub and bearing which is @ $200.00 ish... or of course back the factory way.

[lskrg]

New to the board but had the exact same issue on my 91 C-2. I had to replace the fan. I found a very small crack at the base of one of the fan blades when I visually inspected it. After I removed the fan, I found that the fan was balanced from the factory by drilling holes on the backside. Three holes were very close together and very deep. They were at the base of the blade where I found the crack. Fan and belts were about $700. Looks and runs great now. I cleaned and painted the housing while it was out. I will try to post a picture of the bad fan later.

[Juan911]

Thanks everyone for your wonderful recommendations. I will start taking my car apart this weekend and see what I will need to replace. I'll keep you posted and upload some pictures too. Stay tuned...

[Fast Corners]

+1 on the fan bearing. While you are in there check the wheel on the belt tension sensor too. The wheel on it starts squeeking after a while...very annoying.

[lucittm]

I tried to replace just the bearing (it was hard to remove) from the wheel hub 964-106-051-30 (part #28) and it seems that Porsche used an uncommon bearing size that is not available as a seperate part. You will have to replace the bearing and hub as a unit if that bearing turns out to be faulty. It is a 17mm by 32mm, double row, INA brand ball bearing, number LD17/32 2RS AH01. If you find this bearing, let me know. I'll buy several.

Thanks,
Mark

[Juan911]

Hi all sorry for the delay. I found a very good mechanic in my area (Orange County). I took the my car there and he right away knew what it was, he then quoted me a price and I agreed. The part was successfully replaced and the car is running fine now. Part #28 was replaced only I didn't have to replace anything else. Thanks again for all of your input.