Wind Causing Sound in Engine Compartment

[KiltClad]

My 98 I-30 (35,000 miles) began emitting a vibration (heard, not felt) on a road trip this morning. It sounds almost as if you were blowing a raspberry. From the drivers seat it sounds like it is coming from just inside the engine compartment from behind dead center of the dash. It positively correlates with speed, occurring at around 60 MPH, dampening at 80 MPH. It happens at lower speeds in a headwind. Adjusting environmental controls (thinking fan blade at the time) and other in-cabin features (radio volume vibrating trash or leaves) has no effect. Thinking it was the insulation pad on the underside of the hood, we foil-tapped extensively with no relief. To my untrained eye, I see nothing loose. By the way, the weather just turned cold last night for the first time this season. Are there any known culprits?

Thanks!

[maxhopper]

Welcome to NICO.

Have you checked all the splash guards under the front end and in the wheel wells?

[KiltClad]

Great idea. I hadn't. I looked and everything seems tight. It is a smaller sound than I might expect from a large surface flapping. It's more like a wire or cable vibrating in the wind. I'll keep looking.

Thanks,

[maxhopper]

Here is a list of TSBs (Technical Service Bulletin) for the 98 Maxima; I'm sure there is a similar TSBs for the I30. Here is a TSB pertaining to wind noise on the 98 Maxima. http://maxima.theowensfamily.com/tsb/NTB99-024.pdf

Also, if you have a moon roof deflector, be sure that it is tight as well.