Interior whistling through A/C

[Nohilow]

New member of the forum here...I've owned three caddies in the past; a '66 Fleetwood, a '69 Eldo, and a '75 Eldo. Loved them all..especially the ride. That is what prompted me to buy my latest...a PRISTEEEEEEEN, IMMMAACCCUUULLATE, 2002 Deville base.  Did I say pristeeeeeen? lol.

The proverbial little old lady dies, husband sells her car, fully serviced with all docs, new tires, full tank of gas, etc....KBB sez $5k...sold to me for $3,400. I'm a happy camper.

Immediately packed it up with wife and luggage and took a road trip to Cali from Oregon....without even checking the fluids...THAT is how confident I was in the quality of this car. On the trip, however, a loud "whistling" noise became evident at about 65-70 mph into headwinds. Tailwinds did not produce the noise. Initially I feared an A/C issue, probably the fan, maybe the shaft or bearings producing the noise. Turning off the A/C had no effect. It was quite intermittent, sometimes being quite prominent and others just under the radar. Slowing down always stopped the noise. Had absolutely NO other issues on the trip...25 mpg at 65-70, full air all the way...probably one of the best auto purchases I've made....however the '69 Eldo in good-excellent for $600.00 was a close second. The '75 was my favorite ride tho...what a boat!

Any thoughts? I saw a youtube vid showing how to change out the blower fan and motor, so that looks like a good place to start, but I'm also thinking the air pressure was pushing some kind of baffle, or duct equipment  in the ventilation system aside and causing a whistle. The wife recorded the sound and as soon as I figure out how to get it on the forum, y'all will be able to hear it.

Anyone else had or heard of such a thing? 

[Bruce Nunnally]

 congrats on the Deville. .  A speed related whistle does sound like a door gasket or underbody shield loose.   Did it seem to come from a specific area? 

[rockfangd]

congrats on the find and welcome to the forum.

Did it happen to change when you hit the recirculate button?

Wonder if the cabin air filters are plugged.

[OldCadTech]

Any particular direction the whistle was coming from? Center of dash. passenger side, drivers side?

Shut the doors on a dollar bill and tug on it - should be tight ( or a 20 since its a nice car ) especially around the A pillar since it was into head winds,

Speed related noises like that and especially directional forces are usually door gaskets as Bruce pointed out. Check the door gaskets for deformation or out of channel areas.

 

[cdgrinci]

Can you rule out other possible areas of whistle; I've had whistles come from my windshield wipers (in heavy winds/high speeds).  

[Nohilow]

Seems to be coming from the center of the dash.... The wife (do-pilot) says it seems to be coming from the area of the center vents. Pretty sure it is not either the windshield wipers, or the door seals. 

I'm attaching a ink to a sound recording we made during the trip of the sound. Give a listen and tell me what you think. I've listened to it several times and the more I listen to it, the more I think it is coming from the fan.(?) Possibly caused when external air pressure coming into the car pushes against the fan and shaft, but the suggestion to check the cabin filter is a good one, but it would actually be a barrier to the pressure, wouldn't it? (?) Seems to be one tone, and a whistling sound of air coming through a seal, I would think, would be multi toned, (?)

Where is Columbo when you need him?

Here is a link to the sound: https://www.dropbox.com/s/yh2u7jtz95jpxbe/2002 Deville Interior Noise.wav?dl=0

I'm actually thinking about detailing this sweetheart myself...clay bar, polish, etc...and will post pictures then...I want to do her justice. You understand, don't you?

The suggestion to check the seals with the dollar bill got me to thinking about maintaining those seals. What would you recommend to wipe on them to keep them supple and doing their job?

 

 

 

[OldCadTech]

I think @rockfangd made a good point asking about the recirc as that would eliminate some of the outside air draw through the climate control system. So check that out with a quick test drive. 

Also, @cdgrinci makes a good point about the wipers, take them off and test drive it also.

The best stuff I found to use on the door seals was a silicone spray we used from GM. I think it was called super lube. 

I think any good quality silicone spray or dielectric grease will work the same though.

I listened to the sound-track several times and I admit it does sound like a blower motor, BUT, if it was, it would stop when you turned off the A/C and it would NOT be vehicle  speed related.

Remove the trim around the wipers before you put the arms back on so you can see the bottom of the windshield and check for missing or dried butyl sealer along the bottom of the windshield and tape it off, It might be a little ugly and messy but tape the windshield completely off around the windshield trim, completely cover the trim with the tape. Then test drive and see if the noise is still there.

There was on some years a little motor that would draw air in for the in car temp sensor but even it would only run when the climate control was on. I don't have an '02 manual so your vehicle may not even have it or with the dual climate control maybe they changed the design.

Another place to check is the hood seal near the windshield for splits or any missing sections due to rodent damage

[BodybyFisher]

3 hours ago, OldCadTech said:

There was on some years a little motor that would draw air in for the in car temp sensor but even it would only run when the climate control was on. I don't have an '02 manual so your vehicle may not even have it or with the dual climate control maybe they changed the design.

We have seen this before.  There is a little motor that makes noise when it goes bad sort of like the little cooling fans in computers.   Look for a small vent about 1 inch wide on your dash and listen carefully there.  Its called the aspirator motor and the 2002 does have one, its AC Delco 155730.

[KHE]

I would not suspect the blower motor - it will either work or not work.

The sound file would not play for me.  Is the sound a droning noise?  I have had a loud droning noise on my '05 Deville but it was very intermittent and could not get it to act up to troubleshoot it.  It hasn't done it for two years so I forgot about it until reading this post.

The aspirator motor that BBF suggested would be a good place to start.

[cdgrinci]

To me the sound was like a vibrating reed (as in a wind instrument); that leads me to believe that you have some loose trim that is setting up a harmonic when conditions are just so.

[Nohilow]

It has been very hard to reproduce the sound . It's like having to go to the doctor and once you get there, your symptoms disappear...

So I cleaned out the other side of the garage which has been the "catch all" area, gave her a good vacuuming and wash job, and moved her inside so she is protected from the elements.  

I may have to wait for a trip into the mountains again where it manifested itself the first time...or a very windy day. Stay tuned, I'll have the wife vid it this time and maybe that will help. I may also change out the blower motor (they really aren't too expensive),

[Bruce Nunnally]

Intermittant problems are harder to solve, but more rewarding once you do figure it out

[Nohilow]

On 7/1/2016 at 9:22 AM, cdgrinci said:

To me the sound was like a vibrating reed (as in a wind instrument); that leads me to believe that you have some loose trim that is setting up a harmonic when conditions are just so.

And.....WE HAVE A WINNER! 

A recent trip produced the sound again, and a large truck spitting rocks gave me a pesky crack in the windsheild across my passengers view. 

Being the annoying, overly protective owner that I have become, I made a point of telling the windsheild guy about me PERFECT 14 year old car and wanted it to be in that condition when I left his care. Wisely, he said..."Let's take a look..." and proceeded to show me the little nick's and scratches around the windsheild that my rose-colored glasses had missed. Along the way he pointed out that  the trim at the top of the windsheild on the driver side, was sticking out a small way and definitely exhibiting a LESS- than perfect state.

"Oh." I humbly acknowledged.

Following his windsheild replacement, the trim was definitely tucked down closer to the body, AND.....following another trip this weekend....a quiet, WHISTLE-FREE trip, I am happy to announce that I believe cdgrinci nailed the issue in the least amount of words. THANK YOU!

Thank you, also to everyone else who took part in this puzzle, and it is indeed rewarding when these issues are solved. Thank you, Bruce for providing this forum for us.

 

[BodybyFisher]

[BodybyFisher]

Thanks for reporting back the fix.  This is great info. 

 I actually had this on my wifes Hyundai Sonata (junk), the windshield was replaced before we purchsed it and leaked air at highway speeds, took it back the next day and had to strong arm them to fix it...  it was removed and resealed and no more noise.  Their service department was pitiful.  It had a bad stabilizer link and they told me the bump induced noise was normal  I replaced the link, noise gone.   The engine needed replacing at 29K...due to loud bearing knock, that they tried to blame me for saying I didn't change the oil  me?  right