Well, on the way to work this morning the heater definitely worked... it was hot enough to "burn my face," as Kevin said. I wonder if maybe I jostled a loose connection last night? Who knows. The noise humming noise is still there. So... I now think the two things are unrelated.

Time for the stethoscope...
-David

 

hahaha, yeah me too David.

Mine was very odd because it was only for a few seconds on cold startup... which reminded me of a belt whine. It was clearly coming from somewhere in the vent/gauge area of the dash, but would go away pretty quickly. It did it numerous times. Once again though, I haven't even put a close ear to it to even begin tracking it down.

You might want to yank the gauge bezel... it's not a big deal and lets you get in there pretty easily.

 

do you have airbags? my old car would briefly hum while running start up tests on the bags.

 

No airbags or ABS on mine... your basic vanilla 944.

I wonder if the reason the noise in my car is so hard to locate is that it might actually be coming through the vents. In other words, I'm thinking it's coming from around the blower motor. I'm guessing this because when I was under the dash last night it seemed to be coming from up at the top and center, near the firewall. I'll try to get my hands on a stethoscope soon.

Thanks for all the ideas!
-David

 

Kevin's noise might be something like that... a startup test?

 

Mine has an intermittent whine in that general area, along with some strange clicking, which I think is one of the HVAC actuators going bad.
I never pinned down the whine. Spent a long time on it, and eventually gave up.
It's tough, because every time I would get upside-down in my seat, looking for it, it would go away.

 

Hmmm "airbag startup test" ... if nothing else, it'll oooo and ahhhh people when they ask "what the hell is that noise?!"

I've never heard of this though... what "test" does it perform? There are two states of an airbag: no voltage, and voltage.... aka "kaboom."

 

I'm back to thinking my noise is vacuum related. Possibly coming from around the brake booster. The pitch of the whine seems to be somewhat related to RPM, and one component is intermittent. If I'm slowing to a stop, I'll hear one sound and as the car stops (with the brakes), I'll hear the second sound come in on top of the other. But both are there usually when I first start the car and it's at idle. Very funny.

There is no radio or speakers in the car, so I doubt it is ignition noise. I know that sound…

Actually, about 12 years ago I had a '72 Toyota Corolla which had a similar noise.

Gotta love old cars.
-David

 

FletchDm.... You seem desparate....

Maybe its a german hamster in an excerise wheel connected to your drive train.... and here you thought we had pistons in our cars...

 

Hahaha!

I'm not so worried about the noise, actually. I like your hamster theory though! I was basically wondering if it was a common thing that I just hadn't found in my reading to date.

The car is running quite well, but I just don't follow the idea that "it's an old car... it will make noises." I like to know what noises the car normally makes so I can tell if something is different or wrong.

thanks!
-David

 

I know where you're comming from. Every morning when I start my S2, I listen intently for noises. I only switch on the radio on about 5-10 minutes into the journey. Often when I get home, I leave the engine running and pop the hood and watch the engine and belts and listen for noises. My neighbours link I'm nuts, but I know exaclty how my car should sound.

Good luck finding your humming....

 

"I’ve noticed a hum coming from behind the gauges with the car stopped and the engine at idle."

So what kind of a tune is it humming? Is it a bored kinda hum, like it doesn't want to wait at the light? ALso can you pick up a nationalistic hymm of any sort???

There's a little electric fan that sucks air in from the dash next to the cigarette-lighter. This air temp is then measured for the air-con system.

The other sound you might be hearing is the main fan itself, which never turns off. Even with the switch in the lowest position, it's still ON. Do a test with the car OFF, but turn the key 2 clicks to the ON position without starting the car, do you hear it then?

 

Thanks for all the input, guys. It has been raining a lot here so I haven't spent much time out at the car (no garage). I'm pretty sure the noise is only there with the engine running, but I'll have to get back to you on that. It definitely seems to be loudest on the driver's (left) side.

-David

 

Well, I think I've resolved the noise issue. Using a stethoscope, I found that the brake booster check valve was really buzzing away. Then, almost by accident, I found where the small line leads from the check valve. There's a little chamber next to the battery (not sure what it does... a dampner or resonator?). Anyway, the vacuum line connection had come undone. I wanted to pull the battery anyway, so I did that then hooked up the vacuum line and vacuumed out all the leaves which had collected in there. When I got the engine going again, the noise was gone and the check valve wasn't buzzing anymore.

So, if you hear a strange noise... look for this.

-David

 

You'll just have to get your head under there to see where it's coming from.