Windshield "Whistle" at 78+ MPH and High Outside Temp

[BKH]

Ok - I did a forum search and read all the previous postings, but I'm still not sure the forum holds an answer for what occured this past week. If it does, I must not have used the right search terms.... Anyway, here is what happened:

While on an otherwise flawless road trip, a LOUD whistling sound started at the windshield, but only under the following conditions:

Outside temperature: At least 88 degrees (would not occur at lower temp);
Speed: 78mph and higher (would not occur at lower speeds);
Vehicle: Stock. Standard grill, no crome add ons.

There was no "popping" sound as mentioned in the windshield TSB, and this was much more than just wind noise or an air-leak. I tried turning off the HVAC and that did nothing. Only lowering my speed would make this go away -- until I tried the following:

Turning on the windshield wipers would eliminate the sound once the wipers were at their vertical position. Once they started to go back towards their horizontal, resting position, the whistle would resume. Rather than drag my wipers across a dry widshield, I decided to use a LOT of wiper fluid. To my surprise, the wiper fluid appeared to cool off something - either the wipers or the windshield, or both - and the sound would go away for a while. So, it appears the sound is caused by something temperature dependent.

As summer is approaching and this is such a great road trip car, I have to find a solution. It would be torture to have to drive this car under 78mph!!!

I know this is the type of problem where a service department would just write "cannot duplicate problem" without even bothering to drive to a freeway and get it up to speed - let alone do it when the temperature is high enough.

I have checked the wipers and nothing looks out of the ordinary. Could they possibly be adjusted just a bit too high so that they are interferring with the airflow? If so, I'm not sure how the heat factor comes into play.

It looks like others have had similar problems. Has anyone found a successful solution?

Thanks in advance for any advice.

PS: MPG over 2000 miles ranged from 22 to 28! Though the A/C was on all the time, the MPG really seems to decrease when the temperature gets past 85 degrees.

[Northern Rider]

That's a head scratcher. I haven't heard a problem similar to yours described here before. and, believe me, if there is any reoccuring problem with the 300, we know about it here on this board.

The 300 cabin is very well sealed and normally very quiet at high speeds. The exterior design seems to not produce any loud wind noises. that means something is wrong. I suspect you have an air leak around the windshield somewhere that is forcing air through a tiny fissure (thus the whistle) from outside into the cabin at high speed in hot air.

The heat may be causing something to expand, causing the opening. Moving the wipers seems to disturb the airflow and stop the whistle.

I would try the dealership first and point them towards a possible leak in the windshield seal. That should be covered under warranty.

[joey]

Maybe this 2005 TSB applies to your 2006 car.
It is a long shot.
I occasionally get whistling noise, but usually only when it is windy and/or strong cross winds. I get a lot wind noise from the windows, around the door mirrors.

Windshield Header Buzz Or Humming Sound
http://www.wkjeeps.com/misc/LX/TSB/TSB_2302304.pdf

SYMPTOM/CONDITION:
In warmer weather the vehicle operator may report a buzz or humming sound from the upper front windshield area particularly at speeds above 45 mph (72 kph). Some vehicles may have been built with the upper windshield molding partially rocked forward. When air passes over top of the tail section of the molding it may vibrate creating a buzz or humming sound and is more likely to occur in warmer ambient temperatures when the molding material is more flexible.

[DanRealtor]

It's the seal aound the windshield, At the top. Mine does the same thing no since I had my windshield replaced. I will post the renedy after it's fixed.

BTW: It stops at about 120mph

[color_me_c]

Hello... Posted this in another forum... reposting here. This might help you replicate the noise for your dealer (haven't had a chance to visit mine yet...so I don't know if there is a DCX fix for it)...
**********
I've had the same problem at 85+ mph. Especially frequent on windy days or when overtaking large vehicles (cross-wind/buffeting). High pitched whistle (sounds like a tea pot...or morse code...exactly) comes and goes.

Just yesterday I found a way to re-create the sound ON DEMAND while driving. Find a nice open road with no cops, get up to 85-90, and then apply moderately firm pressure with your right hand to the inside of the windshield. You'll want to press right along the top edge of the windshield...in the center...basically just in front of the rear-view mirror along the black edging of the windshield. Works every time for me... the longer I apply pressure, the longer I get to hear the tea pot. Now that I can (finally) recreate the problem, my dealer's going to need to find a way to fix it.

Hope this helps others. Post again if anyone gets a resolution from your dealer.