Footwell blower fan repair

[Will.birkinshaw]

I have a 1989 3.2 Carrera and both footwell blower fans make a very loud squealing noise on full blast and a slightly lesser, but still annoying noise at low power.
Libricating the motors does not seem to work and if they are anything like the A/C blower fans, Porsche replacements will cost a fortune!
Can anyone advise me on how to extract the motor without damaging the body, as the fan seems to be pressed on to the motor spindle - as it has no grub screw or other obvious attachment mechanism.

 

[plhorner]

Will,
I took mine appart last year (or the one before - time flies), I don't remember there being anything too difficult to it. I seem to recall some spring type clips holding the two halves of the blower body together, remove these and you're right in there!!
However, they're now starting to squeal again on full chat...... I might try a different type of oil or grease this time, I expect the heat might be having some sort of effect.
Regards,

 

[Guest]

One would suppose that they are phosphor-bronze bearings, and oil impregnated, for long life, but maybe this is not the case. (I have replaced mine once in 9 years).

Can you replace just the bearing ? Just the motor ?

 

[Will.birkinshaw]

Phil
Thanks for your comments, but did you manage to take the motor out after you had split the housing and separate the fan?
I have managed to do this when the fan is metallic, as in the A/C condenser blower, but not with these which are plastic of some kind.

Regards

Will

 

[plhorner]

Will,
No, i kept the fan actually on the shaft. I reckon you'd struggle to split them appart without permanent damage. However, you can get access to all parts of the motor without having to do that anyway.
Good luck with the repairs,

 

[Guest]

In my experience there was nothing wrong with the motor of the fan at all. The fan part on mine seemed to have moved toward the body and the plastic of the fan rubbed on the body eventually melting and then seizing the fan to the body.

Its strange that they fail in this manner. It wasnt that the motor had worn laterally as there was very little end float. Its seems like the fan blade just creeps towards the motor housing until they touch. This is odd as the fan blade is lowest when in the car so you would think it would go the other way if at all. I guess its to do with the dynamics of spinning things.

I managed to seperate one of them and position the fan so it didnt rub but the other wouldnt budge without some brute force and I ended up misaligning the moter in its bearings. Had to get another from PorscheApart.

If yours are not seized then I would try pulling the fan away from the body by 1 or 2 mm. Its only a push fit (pretty tight though) It might give you enough clearence and buy you some time.

Cheers

Andy

PS: You should consider that these things have been known to catch fire. So you repair failed ones at your own risk. Replacement may be the best policy.

 

[Will.birkinshaw]

Andy
I have separate the motor from the fan now and the motors (both left and right) make this noise on their own. Separating the motor turned out to be very easy (and resulted in no damage) with a little heat applied from a heat gun directed at the fan mounting boss.
My noise seems to be coming from the brush assembly which resonates - but immediately stops when I apply a little pressure to one or both of the brushes. I cannot see or feel anything else wrong with the motor. Unfortunately I haven't found a way of stopping the noise without the use of my finger!
Not being one who easily gives up, I will find a way of fitting a standard Bosch motor as replacement. The one used seems to be very similar to a Bosch but with modified DC connections.

Will

 

[plhorner]

Will, is it just a case of replacement brushes ? It's possible that they have worn down to such an extent that the springs no longer provide enough load such that the brushes resonate during operation.

Regards,

 

[Will.birkinshaw]

Hi Phil
I did think about this but there should still be a lot of life left with the remaining brush length. The sping load has certainly been reduced but replacing the brushes does not seem easy - if possible. It may be that the heat over its life has just weakened the springs.


Regards

Will