HELP! ......... This whistling sound is driving me NUTS!

I own a 1994 Chevy G20 conversion van with 60,000 miles. I have a whistling noise coming out around the heat and air windshield defroster area. It starts and stops when the van is moving, it will slow down and stop as I
slow down and stop. It also seems to happen more in the mornings then later in the day (but not always) I have sprayed some rust proofing sealer around the blower motor air cond. housing. I unplugged the blower motor (to be sure it was not going bad). I also thought it may be coming from the passenger vent window. But none of this has worked! PLEASE someone must have had this similar issue and must have something else for me to try before I go any more insane! TIA Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
greg
try this .. while driving at the speed the noise is the worst .. have some one push on the w/shield in different areas .. if the tone of the noise changes then you know the w/shield seal has failed .. now i tell you this .. don't use your feet nor do you have to be powerful .. i have done this many times to find strange noises..
do you have a roof rack .. they can do the same thing .. next trick is to take masking tape and cover body seams and sharp edges .. then roadtest if noise gone start taking off the tape .. if still there you have not covered the area and need to keep putting on the tape
good luck
paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks, now the tape is an idea I will try.
Greg

changes
times
covered
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.