nickpapp

I am getting a buzzing noise when traveling on smooth or recently resurfaced roadways. It comes on at about 78mph and remains till about 85. The noise sounds like a metal buzz - like something is vibrating. It can go from barely noticeable to really loud. Seems to be coming from behind the dash. Did the usual troubleshooting while driving - A/C on and off, changed which ventilation setting was being used. Touched all the dash surfaces but it doesent affect the noise.
Has anyone experienced what seems to be a harmonic issue?
TIA
Nick
2004 Base, 6MT, completely stock.

dkmura

iTrader: (64)

Nick- this kind of "buzzing" behind the dash isn't a common complaint of the Z33. How long have you owned this Z? Has the buzzing always been there?

nickpapp

I have had the car for only a month. Miles are relatively low, 78k.

travlee

iTrader: (8)

stock radio or aftermarket?

nickpapp

Stock radio. The noise seems to be sensitive to road surface. My tires will be replaced in a few months, and perhaps the wear on them is causing this? Dont know. It would be better and easier to diagnose if this happened all the time.

icer5160

iTrader: (4)

There's a common metallic rattle that can start happening on the passenger side of the dash. It's the steel knee brace that sits behind the lower dash panel (under the passenger airbag, above the footwell). Other common rattles can come from the passenger A-pillar area or from the windshield defrost vent lightly vibrating against the windshield.

To diagnose/isolate, just go for a drive with a passenger. Have them put moderate pressure on the panels in these areas to see if the noise changes. The knee plate one won't be easy to isolate with hands alone, just have to take things apart. I've experienced all 3 of these. As you say, these noises are intermittent and require a specific combination of speed and road surface condition to recreate. Typical causes are panels lightly tapping each other due to loose fitment or being poorly secured, or hidden piece of the wiring harness is tapping/rubbing a panel.

For interior wiring harness noise issues, I use to help quiet things down. Great stuff for noise reduction.

Hope this information helps!
Cheers
-Icer

nickpapp

Thanks so much for your insight. I will investigate when I get a chance and will post back. This forum is great because of folks sharing their knowledge. Thanks again!!!