Porsche Enthusiasts Club Forum

My car's developed a really bloody annoying high pitched buzzing noise which comes from inside the dashboard whenever I go above about 75 to 80mph

I've tried turning the heater fan on full blast and moving the heater controls around but it makes no difference. I'm sure the noise has something to do with the heater or ventilation system and is caused by the passage of air at high speed into the front scuttle or passenger compartment....

Has anyone else experienced the same thing and cured it or have any ideas?

It's probably the other half trying to tell you you're going too fast

Good point that Martin, she actually can't stand the car so she rarely gets in it. Shame......

I'm hearing you Karl. I can count on one hand the amount of times the good lady wife has been in my car.

With regard to your buzzing, are you sure nothings dropped down the back of the dash and is rattling about at speed?

Ben

I had the buzzing once on an Escort, it turned out to be the speedo cable. I don't know the Porsche set up, but might be worth a try. Just to point out that I would never advise someone to "disconnect it at the gearbox and see if it still buzzes when you floor it on the bypass". But let me know how you get on.

Lee.

Could be a leaf? Only the early cars had speedo cables. Yours will be electronic. A load of c**p flew out the vent & covered me yesterday! Think it was somthing to do with speed....

I'm quite sure it's nothing that's dropped inside the dashboard and I'm convinced it's caused by the passage of air into the heating and venting system. It's as if somethings not quite seated properly and it begins to oscillate at a high frequency like a read valve on a two stroke engine.

I'll see if the scuttle vents are clean and secure and hope that I don't have to delve into the bowels of the dashboard....

BTW I spent ALL of yesterday afternoon trying to re fit my passenger side door handle.

I'd taken it off to replace the two black plastic gaskets which were really scabby. Taking the handle off was fairly easy and fitting the new seals, which I bought ages ago from Forest Fine, was a doddle.

The 'fun' began when I tried to re fit the reconnect linkages from the handle to the door latch mechanism. The 968's are fitted with an anti tampering plate inside the door itself which protects the mechanism from forced entry. It,s a steel cowl built into the window runner/frame and completely shrouds the door latch mechanism and completely obstructs access from inside the door.

The workshop manual is no good at all, 'cos it refers to the method of reassembly used on the S2 which isn't fitted with the anti tamper shield.

Someone's had a go before me in the past and the top part of the rectangular door handle aperture is distorted and the paint is cracked. It's not too big a disaster because the handle and its plastic seal covers all this over; that's if I ever get the damn thing back on again!

(I actually posted this once earlier this morning, but my text 'disappeared'. Strange...)

Thanks for the replies chaps and have a nice day!

It isn't the little electric fan behind the dash which blows air over the sensor for the heater is it? This runs all the time the ignition is switched on.

It's funny but I only just noticed that fan for the first time this evening! I need to get the scuttle panel trim off and have a right good look at the air intakes for the heater system. On the S2 these intakes have a mesh grill which is removable so I'm hoping the 968 is the same....

I had the same annoying buzz from behind the dashboard. It turned out to be the black plastic cover under the bonnet, the one that covers the heater blower. It had become unattached at the off-side corner - so a blob of glue fixed it back in place and no buzz since.

windscreen wipers are sometimes the source of buzzing at speed.

Thanks to everyone for the ideas and advice. I'll look again this weekend and hopefully get to the bottom of it.
Cheers