paullusjoe

My 1988 928-S4 makes a continuous "chirping" noise whenever I use the air conditioner. It seems to be coming from behind the glove box (?) and only occurs with the AC on (not the heater). The noise is quite loud and can be plainly heard at all blower speeds (except maybe the "tornado" max setting). It does NOT vary in speed or intensity with the blower motor. Please help as I am considering enlisting the services of a Jiminy Exorcist!!!

Joe '87 S4

I had the same problem. Annoying as hell. Your fan's bearings are bad. Install a new one.

928drvr86.5

a Vacuum leak at one of the flap actuators perhaps?

IcemanG17

It could be the center comb flap going bad? But thats more of a clicking-clacking noise as it flaps back & forth?

Joe '87 S4

If it's chirping, it's the fan. It's been almost 2 years since I fixed that and now I can hear that damn awful noise in my head again. Get it fixed before it drives you crazy. When I changed the blower motor, I rarely if ever have the "phantom blower" engage now. Another reason to get it fixed. I assume the resistor pack or what ever caused the phantom blower was also changed at the time. Another plus is the air output increased after I had the new fan installed.

Marine Blue

I had the phantom blower problem, hasn't been a problem since the new battery but I haven't had enough time to determine if it will come back. My car also occasionally has a high pitched chirp when the fan is running, it is very intermittent which is weird.

How difficult is it to change the blower motor? If anyone has paid to have it done, what is the estimated cost?

Joe '87 S4

I paid to have it done but I'd have to look up the cost. Something like $300-$400 for the blower and about the same for installation. So around $700-$800. It took a few hours because the hood was removed and I think a bunch of other stuff to get at the blower. But, it was well worth it because I had it fixed a few days before I drove the car from San Francisco to Los Angeles. Didn't want to listen to that thing for 7 hours.

paullusjoe

I initially suspected the blower motor fan (or a loose motor) as the culpret but don't understand why it never chirps with the heater on... It's the same motor blowing the air isn't it? (BTW...I've got the phantom blower problem too.)

IcemanG17

The phantom blower is normal....its a cooling protection for the original circuit.....annoying, but normal

Joe '87 S4

The phantom blower is normal when it works as it should. Mine was going on constantly. Since fixing the blower, it's only come on maybe 3 or 4 times in the last two years.

the flyin' scotsman

A 'chirping' sound is more than likely the HVAC blower motor which in my experience only gets worse to the point its screaming or not working at all. I asked the rebuild question when my blower was dying but never got a blow by blow bearing/motor replacement detail so I replaced the entire unit. You need to remove the hood, the plastic piece at the rear of the engine bay and the 3 screws that hold the motor in place (2 on top, 1 below). Have a look at John Pirtles or Tonys site for a good detailed descriptions.