bureau13

I have not had an opportunity to play around with a "known good" 928 HVAC blower fan so I don't know if mine is working properly or not. I do know it moves a LOT less air than the fan in my 924 Turbo from four years earlier, which seems wrong...

Basically, if I'm turning on the AC I am almost always cranking the fan up to max speed. Even there, it makes a lot of noise (sounds like wind noise through the ducts, not so much fan bearings) but doesn't blow that hard. The lower speeds are barely distinguishable from each other in terms of air movement. They do get progressively more powerful, just...very small steps.

The second half of this question: If it sounds like my fan is working more-or-less correctly, how much better are the replacement fans that are available? If they move significantly more air than a decently-working stock unit, then I should probably upgrade before summer. If not, then I need to determine for sure if mine is working properly or not before I pull that trigger...

NickTucker

On mine the bearings where pretty dry and the fan didn't move a lot of air. Ended up destroying my blower resistor.
New fan motor from Roger fixed my issues.

YMMV

Wisconsin Joe

I may be way out in left field on this (wouldn't be the first time), but what does the "intake" area of the HVAC look like?

I had really weak airflow, even with the fan on high.

I had to go into the HVAC intake, in the cowl area, to pull my resistor pack, to fix my "magic blower" issue.

When I pulled the rubber sleeve thingy back, and looked inside, there was a LOT of dust, lint, leaf particles, and assorted other "gunge" in there, on top of the A/C evaporator (or whatever the 'radiator looking thing' in there is).

Cleaning that out gave me much better airflow.

bureau13

I did check that when I had my dash out and replaced all of the actuator diaphragms...it was fairly clean (surprisingly).