MainePorsche

Guys,

Just noticed this evening my driver's side fan is making a new noise, and appears to be 'sticking' a little when I flick it to move. The other one is freer when I do the same thing. A quick look when I rotate manually, and I see nothing externally impeding the motion. When the fans turn on, they both seem to operate with the same vigor. It is just the driver's side is now noisy - kind of a 'rubbing against plastic' sound.

I'll get into it tomorrow, but I wanted to ask first if there is a known bearing issue or things of the like that I may be up against. Electrically, the system is fine.

Thanks In Advance.

Craig

928Myles

Craig,
there is a replaceable bearing in the front of the fan unit along with a bush in the rear.
I posted a write-up about bearing replacement here: https://rennlist.com/forums/928-foru...iator-fan.html.

Could also be something in the motor creating additional friction.
Several people have tried to find replacement brushes for the motors but I am uncertain of their success.
Myles

MainePorsche

Myles,
Thanks for the reply. I had just finished reading your great write up, and work, on the reconditioning. I don't have riveting tools, but I soon will. Thanks again.

NC928S4

I had a similar scenario which turned out to be the fan blade hitting a hose clamp on the power steering reservoir. The entire radiator and shroud assembly would shift towards the rear of the car because the radiator hold down clamps had relaxed. The clamps are brackets with a rubber dampener. I removed the brackets and put a little more bend in them so created more downward pressure on the radiator to keep it in place.

Hope this helps.

MainePorsche

In the daylight (with lights and mirror) I did see a slight rub mark on the shroud at the 3 o'clock position when viewed from the front. However, when manually turning the fan it does not make a contact there. Wondering if the torque of the fan, when operational, can cause a shift of the involved components (?). Will investigate more and report back. No other impediments noted.

mdkelly1

Had a similar symptom with the driver's side fan in mine last year (after timing belt/water pump replacement).

It was most noticeable when the engine was shut off with the fans running. As they cycled down, the rubbing noise would disappear as the load went away.

When the fan was turned by hand, there was no noise and no rubbing on the fan shroud. When the fans are running however, the blades on the fans tend to deflect slightly under load, and one on the left-side fan touched the fan shroud on each pass.

As you can guess, the fan shroud was slightly out-of-adjustment after being re-installed, so it was just a matter of resetting the fan shroud to ensure there were no points where the fan blades contacted the shroud.

MainePorsche

Thanks Dave.
The only work I've done in the area recently was redoing a butchering of wiring to the fans by the PO. The only handiwork against the shroud or the fans was re-clipping the wires in or replugging in the connectors. Not today, but I'm going to get the car up and see about the manual realigning of the shroud seating with fans on.

Another aside on this subject for all.
Even though Roger abroad, he got back to me saying this bearing is NLA. From diligent Search I found that Borland used a bearing for a skateboard with number being 608ZZ. The measurement of this bearing is 8mm x 22mm x 7mm. Without doubt Borland to be trusted. I looked at the bearing at a local shop and it does appear to be the same size as the ones that Myles and Borland had removed in the photos of their write ups.

928Myles

Craig,
that is correct - common bearing often used in skateboard wheels. Pretty cheap to.

Myles

MainePorsche

Myles when I said that Borland could be trusted with the bearing dimensions, I hope you didn't feel any less admiration on my part for the quality of your posts and write ups. You are both Masters of the art.

928Myles

No issue even considered to exist Craig. Just wanting to confirm your statement was correct.

Myles

MainePorsche

Got into to it a little earlier, and when fans would run I noted significantly less noise. When I manipulated the motor support bracket (at 10 o'clock when front facing), the sound would wax and wane all the way to absent. This doesn't exclude the bearing, but it may just be a seating issue (I hope). I have bearings set to go, and will pull the shroud if need be.

MainePorsche

On the further inspection today the problem is not a shroud, or fan, seating issue. Definitely a worn bearing issue. Now a kind of screechy metallic sound too. Oh, to pull the shroud...

MainePorsche

Guys,
A bit at an impasse. Shroud out and L fan off. Removed retaining clip, but can't get blade housing off. I've been following Myles' write up, and he says to pull, shake, tap it off. I have it on the work table and have tapped it vigorously, but don't want to go further with the vigor. It feels like it is seated on the shaft pin.
How do I get this thing off ?
I don't want to use brute force until I am confident the little tidbit of information I am missing is seen through.
Thanks.

andy-gts

I am just starting this project, waiting to see how you get that off !!!!

Kevin in Atlanta

Me, too. Subscribed!