Noise from under dash


Old 04-30-09, 06:53 AM
Thread Starter
Join Date: Feb 2008
Posts: 6
Noise from under dash

I've got a '93 Bonneville that gets a "whirring" noise from under the dash when you get over about 50 mph. Its kinda like a piece of plastic vibrating at high speed. It seems to be caused by air coming in and is worse going into a strong headwind. Have tried blocking air intake in front of windshield and can move heater, vent and fan controls to different positions and it doesn't make any difference. Is worse at cold temps. Have also unpluged heater fan.
Does air come in any place other than in front of windshield that a person could block?
Also have met a large truck and had the rush of air cause it to quit making the noise for a short time. Don't want to have to try and tear dash apart.
Sponsored Links
Old 04-30-09, 11:48 AM
Join Date: Jul 2006
Location: Virginia Beach
Posts: 221
Make sure there's nothing stuck underneath like a swath of plastic or something. Other things could be a leaf has gotten stuck in the vent system or there's a hole in a seal in the firewall.....Just some out of the box ideas.
Old 04-30-09, 11:59 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,023
If you can have someone put a length of hose to their ear and listen under the dash as you drive, you might help isolate it. Seems like some cars used a sort of sticky tape to seal around firewall penetrations and such.

Also..are you sure its under the dash? Could be something under the car (heat shield, fan shroud, etc) that is transmitting the noise to the interior.
Old 05-10-09, 07:48 PM
Join Date: May 2009
Posts: 2

I had something similar. I pulled the vent hoses and there was some type of tape (or plastic coating) that had came off and was lodged in there. When the heater was on, the flapping around was much more obvious. Will only tak a minute to inspect the hoses. Good Luck on it...
Old 05-10-09, 09:30 PM
Join Date: Jan 2007
Location: North Central Indiana
Posts: 912

I would look for a peice of plastic on the out side vibrating in the wind.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes