Meatball964

Recently developed a noisy metal ringing sound more apparent b/w 1800rpms & 2500rpms (worse on deceleration). Upon inspection i noticed scrape marks on the fan housing at the 6:00 postion...pulled HARD on the fan blades (very slight play MAYBE 1/16in.)
My question is this...
(1) I recently drove over a speed hump too quickly & bottomed out the engine ....could this have caused this slight misalignment and can this be adjusted (re-torqued) or is this just a coincidence and the fan bearing needs replacement.

(2) I've owned this car for 7 months now (96 C2) and looking at the service records i see all belts were replaced about 9k miles ago (2 years ago) and the service tech noted the following upon a general inspection....
"inspected fan bearing for play due to rub marks on fan shroud. The fan shroud has been over torqued causing it to be misshaped. Removed the drive belts, clearanced the fan w/a piece of course sand paper until the necessary amount of air gap was acheived. Note: the proper repair would be to replace both the fan & shroud approx. $1800 in parts." The owner apparently declined.

I have attached pics for reference....thoughts on how far to go ($$$) with this repair ?

ble2011

If it were me and to save on costs (after looking at your second pic), I would start with replacing the fan itself with a used unit. Hopefully, the shroud is not too out of round and that would correct the issue.

Stealth 993

You can seat the fan shroud a little off & cause the fan to scrape. Remove the belts, unstrap the housing, reseat it, & retorque. Then turn the fan by hand to make sure it's spinning freely. It does look like you so have fan damage, so it might all be a lost cause.

AOW162435

A new fan from Sunset Porsche should be around $400, including the fan bearing.


Andreas

Meatball964

The fan does not yet appear to be damaged....just the paint/coating cracked (won't know how bad until I remove it). Certainly an opportunity to paint the fan and housing.
Not sure i want to replace all the belts with only 9k on them....maybe just reset tension.
Thinking i Should I go ahead and replace the fan bearing while this is out.
Source for the 12pt Porsche tool ?

Paul902

The tool required is a 10 mm XZN. Nice stubby 3/8 drive one available from Snap On for about $10.

Good luck!

Meatball964

Ok, installed new fan bearing on alt. shaft and was able to press it (by hand) all the way down to the base. Now i'm trying to slide the fan on the shaft and still have about a 1/2 to go (see pic) and won't budge any further. Already soaked it w/PB Blaster....
1. Do i cut a section of PVC and w/a wood block...tap until its all the way down or....
2. Buy (3) LONGER 5mm bolts and slowly tighten each one...

Need some wisdom here before i start any hammering on this fragile piece (fan)....

k722070

take it back apart,
put bearing and shaft in freezer,
put fan blade in oven and cook for 15 minutes at 150 degrees.
remove parts from freezer and oven and slide them together easily.

TMc993

After seeing photo #2, I would have the fan magnafluxed/x-rayed before I reinstalled it. Paint and similar coatings generally have a fairly significant level of elasticity and don't usually crack unless the metal beneath is cracked. If one or both of those blades broke off, the resulting damage could be significantly more costly than a $400 fan.

chris walrod

Just replaced a fan bearing/hub this weekend due to noise after a belt replacement.

Meatball964

Interested in your thoughts Chris.
In your experiance, how often have you seen these fans implode ? and if so what is typically the extent of the damage they can cause ?
I've done a search & they seem to fail at the tips (making contact w/housing perhaps) not so much at the base where the paint cracks are (see pic #2)
Still debating on moving forward w/existing fan or not.

tigerrat

If those are cracks and they are from the fan hitting the shroud, wouldn't they be on the other side of the blade given the rotation? If you lightly tap the blades do some ring different than others? Just some ideas but if I was in any doubt, I would replace it. Ken

chris walrod

Thankfully never have seen one come apart, but see cracked blade tips quite often. Mag is brittle by nature and wont withstand shock loads. With your fan, I would certainly have it either replaced or at least stripped of paint with a view to a close visual inspection. I see cracks like you display every now and again.

The fan in the above picture had some contact at the housing, but just tips of two blades were damaged, barely noticeable and with no visual signs of cracking. This is one reason why I cleaned the fan like I did, to give a good visual inspection.

Here is the fan before, very dirty.

IXLR8

Looking at your second pic, those cracks look more than just "cracked paint" but only you will know for sure.

If that were my car, I'd be replacing the fan blade with a new one and using the old blade to make a clock. Who needs the headaches of wondering when it might go.

AOW162435

+1.

I'd bet my Polar Silver junker on the fact that the blades are cracked.


Andreas