GR Yaris Fluttering noise from behind dash at speed

[Duke]

I've had this for a while and and I figured it's about time I tried to figure out what might be causing it!

At much above 140 km/h (87 mph, fact fans) I hear what sounds like something fluttering right behind the instrument binnacle. It's exactly the kind of noise you'd hear if a bag or something was trapped under the car, but of of course I've checked, even removed the undertray, and cannot find anything obvious stuck anywhere.

The car has also had at least two services where, although I haven't mentioned it, none of the techs has ever identified anything untoward either.

It's clearly speed-related, being inaudible under about 120 km/h and get's more strident as you get faster until it gets drowned out by other wind and road noise when you get above 200 km/h.

I'm sure the 'right behind the instruments' is just an audio quirk and the actual source is somewhere else, just audible through the bulkhead at the most obvious point.

Apart from the noise the car runs just perfectly; no ill effects after over a year, and it definitely started at one point about a year or so ago.

Anything anyone can think to check? I can only assume something is loose or there is a crisp packet lodged somewhere that I cannot see!

 

[spectre7]

I've had this for a while and and I figured it's about time I tried to figure out what might be causing it!

At much above 140 km/h (87 mph, fact fans) I hear what sounds like something fluttering right behind the instrument binnacle. It's exactly the kind of noise you'd hear if a bag or something was trapped under the car, but of of course I've checked, even removed the undertray, and cannot find anything obvious stuck anywhere.

The car has also had at least two services where, although I haven't mentioned it, none of the techs has ever identified anything untoward either.

It's clearly speed-related, being inaudible under about 120 km/h and get's more strident as you get faster until it gets drowned out by other wind and road noise when you get above 200 km/h.

I'm sure the 'right behind the instruments' is just an audio quirk and the actual source is somewhere else, just audible through the bulkhead at the most obvious point.

Apart from the noise the car runs just perfectly; no ill effects after over a year, and it definitely started at one point about a year or so ago.

Anything anyone can think to check? I can only assume something is loose or there is a crisp packet lodged somewhere that I cannot see!

Not sure if it is helpful in this case, but sometimes I get fluttering wind noise from my passenger's side A pillar. In my theory it is either caused by occasional rubber seal of door window not flushing perfectly (not leaking or anything, just might be slightly imperfect due to all dirt and stuff on winter roads) or plastic covers that are below windscreen wipers. Happens to me once per few months, usually after opening and closing windows fully and making sure everything in the front is tight it goes away. Also it definitely doesn't help that we can have extremely bumpy roads here so... but once again it might be completely different thing.

 

[Duke]

Not sure if it is helpful in this case, but sometimes I get fluttering wind noise from my passenger's side A pillar. In my theory it is either caused by occasional rubber seal of door window not flushing perfectly (not leaking or anything, just might be slightly imperfect due to all dirt and stuff on winter roads) or plastic covers that are below windscreen wipers. Happens to me once per few months, usually after opening and closing windows fully and making sure everything in the front is tight it goes away. Also it definitely doesn't help that we can have extremely bumpy roads here so... but once again it might be completely different thing.

Thanks, I don't think this is a door/window seal as it's definitely not coming from that area, and is consistent.

I'm thinking it must be a leaf or something caught in the cabin air intake. Need to see if i can disassemble the cowl and check inside.

 

[Duke]

Whetever it was, it's gone.

Seems like it must've been an arch liner or something that was replaced when the front end was fixed after my wildlife coming together.

 

[banzai2]

Have you got front mud flaps? I also get this noise and figured it was likely these. If you do not have them I will have to look elsewhere!