kawi825

I almost think I saw this on RL somewhere but can't find it. Just did Tb/WP, etc cam and oil pump seals, eliminated air pump, capped rear holes, change grommets under brake fluid reservoir.
Now upon shutting my car off I get this weird whining/buzzing for about thirty seconds until it weakens and stops. It's under drivers side dash, never heard it before all this engine work.
I almost think I can hear it while running too. Trying to upload a sound only video of me shutting the motor off and the whine afterwards. TIA

Bilal928S4

Could be a leak from the HVAC system or the vacuum accumulator in the wheel well.

Mrmerlin

look at the brake booster find the blue valve thats connected to the main vacuum line hold it while the noise is happening if its vibrating thats the most likely part

kawi825

Thanks guys I'll take a look

kawi825

Blue valve made me think of "blue hose", which immediately gave me flashbacks and cold sweats..

kawi825

Just wanted to put a close to this one. Might help some if the newer guys I've been seeing popping up. This ended up being a blue check valve exactly like Stan said. It wasn't by the brake booster but instead the one under the gauge cluster, was humming like a bumblebee after I'd shut the car off. I realized there was another one by finding Jim D.'s post on vac diagrams.
I ended up finding my passenger vac line for the lock was disconnected where it entered the door. Thanks for the help, on to my window motors, etc this weekend.

Koenig-Specials 928

Sorry to revive this old thread. Seems it's my turn with a similar noise but mine is coming from the passenger side like from behind the glove box. AC cools the cabin down but the noise is driving to drink and I really really don't need another reason to do so. I followed the advise of similar threads on this subject and disconnected the black vacuum hose at the 4-way by the brake booster. That eliminates the noise completely.

So is it #28 and I need to replace the diaphragm?
Or is it something else?

Please and thanks

joejoe

You can get the whole thing from Roger.

Mrmerlin

you can drop the blower box and replace the pod,
then use the 3 M strip caulk to reseal the edge,
disconnect the battery,
disconnect the blower motor, elex connector and the 3 securing screws for the blower motor to blower box.
NOTE the 3 screws will need to be removed one is inside the car under the blower box,
the others are under the hood one in the airduct.
then disconnect the blue vacuum line under the cowl cover,

remove the computers ,
then drop the CE panel,
then put a towel over the Ce panel,
drop the CE panel support rails.
then remove the blower box nuts ,
the blower box will drop down,
NOTE if there are lots of leaves in the well they will fall onto the towel.

Once the box is out of the way work the blower motor down through the same hole, and service the motor.

installation is,
refit the motor to its general location it should stay in position without the blower box,
then fit the blower box,
be careful with the blue vacuum line,
then attach the motor to the box,start with the inside screw first.
and install the CE panel and computers and battery connection.

NOTE if this pod failed it would be wise to check the 2 pods under the console as these will also fail.

Koenig-Specials 928

Thanks Stan.

I was hoping it was one of the pods easily accessed. So maybe I'll postpone this fix for now until I get all the diaphragms and replace the motor as well and do a complete HVAC rehab. Then I'll be good for another 25 years

Thanks