dukmon

I can't quite place what's causing this buzzing. Though intermittent, it's usually happening more often then not, with no rhyme or reason.

Thoughts?

JohnK964

ccu fan is my best guess

dukmon

Even if the CCU is turned off?

Earlydays

Yes, I'm pretty certain it comes on when you start the car because it draws in cabin air for the CCU in order to regulate the air temp.

dukmon

I believe you're both correct. I have found a thread concerning this.

Thanks!

dukmon

Am I asking for trouble if I just unplug the CCU fan?

Guessing the unit may not be aware when ambient temp is equal to the set temp. I'd have to manually stay on top of a desired temp.

Silvertarga

I posted a thread a while back, used a CCU fan from a Jaguar, pretty cheap on ebay..;. PM Me if you cant find it and I will look up the part number. Swap involved swapping the plug and moving the Porsche mounting bracket to the Jag unit...

JohnK964

I did the same nit sure if it was a Jag one thise fans were used on a b$Tload of cars

dukmon

Hey. Yes, installing a new fan seems pretty straightforward. I hadn't seen your thread (yet) but had read this one:

https://rennlist.com/forums/964-foru...aning-diy.html

I intend to install a new fan, just have too many other things going on right now; probably cannot get to it until this spring. Focusing on work and also getting a different car ready for WERKS Amelia Island.

I see the fans plug. I can easily unplug the fan without yanking the unit out, for a short term fix. Just want to be sure I'm not overlooking some obvious mistake by doing this.

The sound is about to drive me crazy!

JohnK964

Maybe Tore will chime in he seems to knew this stuff pretty dam good

964Luftballoon

Here's a link to Tore's DIY section and a video I found on YouTube below

https://www.bergvillfx.com/categories/diy-section

ToreB

Thanks for the references guys!
I never bother to try to repair the CCU fans. The needle bearings wear out and it starts to make noises like this. This could be mended by oiling and tightening the bearing, but it is time consuming since the bearing cannot be too tight, and won't last very long anyway. The second problem is that the motor magnets weaken over time, and the fan will not start. A quick test is to stop the fan with your finger. If it then just nugdes back and forth and does not start when you let go, it is ready for the bin. (it has been in service for about 30 years!)
Please be aware that the CCU with fan stays active for up to 20 minutes after ignition off. This is important for proper regulation of cabin temp at short stops such as refuelling. The fan is imperative for the CCU's ability to measure and regulate the cabin temperature, so I always recommend to change the fan.
Porsche charges over EUR 400 for the spare, so I decided to make my own at a significantly lower price.
Cheers,
Tore