High-pitch sound while above 80 km/h

[hermesr]

I've encountered a really weird issue. While driving at constant 130 km/h all of a sudden a sound appeared, high pitch, alternating between two frequencies, but constant. Speed does not seem to affect it, but the sound disappears below 80 km/h. At 130 it is very audible. Frequency change seems random, and I can't really confirm if bumps have any effect on the sound itself.

I had it checked today at a local Toyota dealership, but they could not identify any fault. No other behaviour is affected, no warnings, no changes in drivability, consumption, steering, breaking, etc.

Has anyone else encountered this? It's barely 5500 km brand new MY2022. This started after a long drive in the hot at a constant 130 km/h, but appears unrelated to road conditions.

Can't seem to track where this comes from, appears to be more audible when I open a window, so perhaps coming from the outside...

Thanks for any hints!

[Cyker]

Things vaguely like this I have experienced in my previous cars once I hit a certain (Different in each case) speed:

Piece of paper stuck under car (Very high pitched whistle, I imagine like blowing on a saxaphone reed)

Plastic bag stuck under car (Flappy sound into a weird buzzy sound not unlike a vuvuzela (Remember those?  ))

Missing fasteners on one side of the undertray thingy (Sortof a humming sound with a thud every time I went over a bump)

 

[hermesr]

Thanks for sharing. I was thinking about these as possible causes but they did not find anything stuck under the car in the dealership.

The sound itself reminds me of a flute, sometimes endlessly stuck on a single tone, sometimes changing between two or three (not dependent on speed).

Going through slightly rougher surfaces at speed does not really affect the pitch, though it makes it a bit rattle-y.

I am soon to travel 2000 more kilometers, it will be a pain for all passengers to endure through this constant whine for two or three days... Getting desperate already.

[TonyHSD]

Does it sound like a whining gearbox bearings or wheel bearings but at higher pitch? Can you record the sound with your phone and share it with us? Did Toyota checked your transmission fluid level? 
 

[hermesr]

Thanks for your suggestion. I can try recording, but not sure it will be easy to hear. Will try tomorrow. I can't say if it sounds as gearbox whining though. It's a hybrid cvt, so not sure what fluids, if any, go there. In any case, if the dealer wouldn't think of this as a possibility, I'd doubt their competence, mildly put. I had someone in the car withe to listen to the sound, they ran diagnostics too, but said there was nothing obviously wrong...

[RabButler]

See if opening up the central vents on the dashboard changes the noise.

[Cyker]

I've seen people reporting weird tones at speed being traced to the mirrors on occasion, with the fix ranging from cleaning around them to folding them in or out slightly more.

 

[TonyHSD]

26 minutes ago, hermesr said:

Thanks for your suggestion. I can try recording, but not sure it will be easy to hear. Will try tomorrow. I can't say if it sounds as gearbox whining though. It's a hybrid cvt, so not sure what fluids, if any, go there. In any case, if the dealer wouldn't think of this as a possibility, I'd doubt their competence, mildly put. I had someone in the car withe to listen to the sound, they ran diagnostics too, but said there was nothing obviously wrong...

Most likely a normal behaviour. Usually these cars has two electric motors and planetary gear set that rotates at very high rpm’s up to 20k . At these high speeds it is normal to hear some high pitch noises when the car goes into ev mode up to 70mph with your car and also when the system charges the Battery. All these noises are more prominent with windows down. For the transmission fluid in some cases when the transmission been overfilled can create whining noises at higher speeds 80mph , but your car is new and I think not likely to be the case. If  Toyota checked and say it’s ok then should be fine, if not and breaks they will fix it under warranty. Good idea to pay attention to what Rabbutler mentioned about the air vents. 👍

[hermesr]

23 hours ago, TonyHSD said:

Most likely a normal behaviour. Usually these cars has two electric motors and planetary gear set that rotates at very high rpm’s up to 20k . At these high speeds it is normal to hear some high pitch noises when the car goes into ev mode up to 70mph with your car and also when the system charges the battery. All these noises are more prominent with windows down. For the transmission fluid in some cases when the transmission been overfilled can create whining noises at higher speeds 80mph , but your car is new and I think not likely to be the case. If  Toyota checked and say it’s ok then should be fine, if not and breaks they will fix it under warranty. Good idea to pay attention to what Rabbutler mentioned about the air vents. 👍

I'd be surprised if this is an expected or in any other way "normal" behaviour. It did not happen for the first 5000 km, and is rather audible, kind of intrusive. The only "factor" I could isolate was speed - I can't hear the sound below 70 km/h, and it becomes quite noticeable above 90 km/h. I can't notice any correlation to the charging of the Battery or to running in ev mode.

Also - changing vents positions has no effect. Neither folding the mirrors.

Subjectively speaking, it sounds like an electronic sound emitted from a speaker. Not sure what affects the change in tone, but it does not seem to be speed.

If it is anything in the transmission, I'd be getting worried 😟

[Cyker]

The trick will be trying to locate the source of the sound but without a wind tunnel it will be tricky to do while moving at speed!

I have a feeling there's a gap somewhere that is resonating like a saxaphone reed when you get to a certain speed.

Could also be something that's being pushed into touching a moving part of the car when there's enough air pressure from forward speed...

Does the pitch vary with speed or engine RPM at all or is it very constant once it starts?

 

 

[hermesr]

30 minutes ago, Cyker said:

Does the pitch vary with speed or engine RPM at all or is it very constant once it starts?

 

 

The pitch does not vary by speed. When it changes, it is absolutely random. Typically, it is a constant uninterupted sound. More like pne from a flute than from a sax, but that's hardly a helpful hint 😀

What changes by speed is the volume, but I haven't gone above 130 km/h to see if it will keep increasing. Not much difference between 110 and 130 though.

[Cyker]

That would eliminate something rubbing and more strongly point to part of the car becoming a wind instrument  

All I can suggest is look around for narrow gaps that are facing the direction of air flow, maybe look/poke at the undertrays and make sure they are overlapping correctly, as if any work's been done down there and they've been removed, sometimes the lip gets overlapped on the wrong side because whoever put it back on didn't tuck it into place properly.

If there are any motorways near you with concrete barriers you might be able to try and hear if it's coming more from one side or the other, of further back or forward.

 

[hermesr]

So, a short update!

I took the car to the dealer from which I had bought it. We went out for a test so the representative could hear the sound. And... there was no sound! So, somehow whatever was doing that sound no longer is. The one key difference to when I had the sound at speed compared to that demo drive, was ambient temperature. In the latter case it was just 23 C, while previously above 30. Nothing to really point at the likely culprit, but given that sound is no longer present (and let's hope it won't be coming back), I'm happy.

[TonyHSD]

8 minutes ago, hermesr said:

So, a short update!

I took the car to the dealer from which I had bought it. We went out for a test so the representative could hear the sound. And... there was no sound! So, somehow whatever was doing that sound no longer is. The one key difference to when I had the sound at speed compared to that demo drive, was ambient temperature. In the latter case it was just 23 C, while previously above 30. Nothing to really point at the likely culprit, but given that sound is no longer present (and let's hope it won't be coming back), I'm happy.

I believe your car has an active grill on the front. Any possibility this was widely open at the time when the sound was presented 30C and perhaps now its closed for better aero and efficiency. If open widely may let more air in or if open oddly may let air in but increase air flow pressure and cause some air drag that sounded like bad bearing . Just my thoughts. 👍

[hermesr]

I wish they were as inquisitive and thoughtful. But I am afraid that to them "no problem now" is the same as "no problem at all"... Next time I go, I'll raise it as a possible cause, and hope for the best. Thank you for sharing!

[hermesr]

Well, I thought to provide a brief update. The problem got solved by my dealer while doing my first annual check up. It turned out the sound was due to the bars on the roof. The dealer attached some element to the front one, and there is no more whining while riding at speed. As weird as it is, and even more so that this was not previously considered as the culprit by the same dealer, the issue is now resolved.

These are standard bars I got from Toyota and which have never been taken down from the car. Possibly an element got detached while at speed, as the bars are structurally whole.