Hi folks, new kid here with a question. The car is a 2004 Outback, basic model. Lately I've been getting a horrendous screeching sound from under the hood when I hit passing speed on the highway - 65 to 75 MPH (okay, that's actually cruising speed here in northern NJ). It's not constant, and it's not predictable.

 

So I look under the hood where I think the sound is coming from - the rear right-hand side near the firewall, and I see this thingie:

http://www.inpayne.com/temp/thingie.jpg

 

Looks exactly like a horn, but it's not THE horn - that's in front of the radiator. It's not part of the alarm system, 'cause I can't get it to make a noise by setting or tripping the alarm.

 

So what the heck is this thing, and could IT be making that awful screeching sound?

 

Thanks!

Is there a vacuum line or electrical line hooked up to it? or both? It kind of looks like a vacuum diaphragm to me...

Have you checked the condition of your serpentine belts? Tension? Cracking in the ribs?

What's the mileage on your car? Have you had your timing belt / tensioners / pulleys / water pump done lately?

it kinda looks like the horn to me. in an odd place but still looks like the horn.

 

 

are there wires going to it or vacuum lines? anything at all?

 

 

if there are wires, it could be something of that nature (horn,alarm speaker) and it could be shorting out causing the sound.

 

is the sound mechanical? an electronicish sound? maybe sounding like if a banshee screamed into a loudspeaker?

 

 

-Justin

That is the horn for the alarm system. Probably not your noise.

Ah, but when I set the alarm, and then made the alarm go off, the noise came from the horns under the grill. This thing never made a peep!

 

Banshee screaming into a loudspeaker! Yeah, like that!

 

Yes, I see a wire connected to it. I'll have to duck my head in deeper to see if there's more than one connection.

 

My impression was that the screech is mechanical - either a slipping belt, or maybe (please no) something in the transaxle rubbing on something. But when I saw this thing, I started doubting myself.

Grab a bar soap.. hold it on the belts while the engine is running to get some of the dry soap on the belts.. if the problem goes away you need new belts..

I'm gonna guess that it's wind noise from the gusset seal on the passenger side window.

...or maybe it's that cat that's been trapped in the air cleaner for the last month.

 

That soap trick is interesting...

i would say unplug it and see if that helps. it really seems like its a horn.

 

try the soap deal. the schreaking sound under a hood is normal when belts start to go out. mainly because the surface of the belts (and pulleys) become smooth and slip.. (not really a bad thing) but they make that sound too.

 

 

-Justin

I was going to say air cleaner box

If this is what I'm thinking it is this is peculiar to 2000+ outbacks. Many folks won't be familiar with it. You're talking about a really high pitched squealing noise right? It has nothing to do with your engine or trans and probably only occurs during high cross winds - but that might vary.

 

It's something to do with the gutter in front of your windscreen i believe.

 

It sounds really bad, metallic and too high pitched, but ends up just being bad vibrations. I forget the actual issue or how it's corrected but i've read about it.

 

The gusset noise he's talking about is wind noise from the side view mirror/front door glass area. But it's not nearly as high mitched.

That would be too weird, but it actually fits the symptoms! I really does sound like it's coming from behind the dash in the glove box area, which could be anything around that area.

 

Is there a reason it would only show up after six years? Or could it be that I had a new windshield put on just a few months ago - hmmmmm. I'm gonna check the windshield moulding, maybe it's loose.

Hey, I appreciate everybody helping out the newbie, thanks.

Grossgary, you're a genius. Check this out (if you can make it out):

http://www.inpayne.com/temp/gap.jpg

 

The moulding is loose right where the noise is coming from. The stuff is very flexible. I have to road test it, but I betcha that it's vibrating like a reed in a flute when the slipstream hits it just right. I'll take my wife for a ride this week and have her watch it.

 

It's gonna be tough keeping her on the hood at that speed, but it's worth a try.

 

 

 

 

I'll figure out a way to paste it down. This is the fifth replacement windshield on this car (NJ commuting is hell), and with my luck this fluttering rubber thing will shatter it!

I'll figure out a way to paste it down. This is the fifth replacement windshield on this car (NJ commuting is hell), and with my luck this fluttering rubber thing will shatter it!

 

A little duct tape should hold it.

If you want something more aesthetically appealing, a small bead of this between the glass and the trim should do the trick: http://www.shop3m.com/70070385854.html

That or some Window-Weld ribbon sealer. Window weld is much more expensive though and you'll probably end up with about 25 feet extra that you don't need.

I started researching the cross wind noise on my 2004 Subaru Legacy and ran across this post on another site.

 

http://www.scoobymods.com/windscreen-noise-speed-during-strong-t5358.html?t=5358

 

I'm going to try it out.

Hope your having luck finding the noise!

As for what that thing actually is, it is a horn. On models with A/C one horn sits in front of the a/c accumulator. Strange place for one I thought. Check the Haynes manual 12-21. I also checked my car, sure enough....

My car used to make a high pitched squealing / whistling noise when I get up to about 40... Finally found out it was the window seal just above the top of the mirror. I shoved a pit of paper in the crack between the car an the seal and it's gone.... Nothing like fixing your problem on the road. hah.