Whistle from HVAC while in footwell-only mode

[Murds]

Picked up a new LC in October. We had a warm Fall in the NE but now in full heat season. At first I thought I had a door or sunroof seal issue but I have a whistle that is the actually from the HVAC. Easiest described as the sound when one of your windows isn't quite rolled up all the way at highway speeds. After chasing it down there is an obvious whistle coming from the center dash vents when HVAC is set to footwell only mode. In any blend mode (footwell+dash vents or footwell+defrost) or full on dash or defrost it is whisper quiet. I decided to look here to see if anyone else had the issue or maybe there is just a defect with mine. I saw a reference by @Meteor to it in this related heater thread, so this is a design/manufacturing issue. I stuck my boroscope down the center vents to see what I could see. There is a horizontal cylinder with different fluting that rotates its position depending on the mode. No obvious issue. Talked to my buddy who is a Lexus mechanic. He said that the blower box is a unit, and you have to rip the whole dash off to get to it. I am not in a big hurry to have that happen to a truck with 500 miles on it.

Post back if you have the issue and even better if you have had Toyota look at it. If enough people have this issue I will approach Toyota for them to launch an investigation and maybe get a TSB.

 

[RRanger1996]

I have a whistle coming from the driver side vent to the left of the steering wheel. I have my 6 month maintenance appointment next week and will inform the dealership at that time. If I close the vent, its not an issue and that's been my current workaround.

 

[Kevin]

I'm having the same issue. A whistling sound when the heat is set to only blow out the floor vents just as you described. I haven't talked to my dealer about it, but I'll mention it when I have my first service appointment. However, that is probably 2-3 months away at this point.

 

[Madscientist]

My rig does the same- somewhat high pitch whistling noise when HVAC system is directed 100% to footwell space- much quieter when routed through all other venting options.

 

[uraniumrich]

Picked up a new LC in October. We had a warm Fall in the NE but now in full heat season. At first I thought I had a door or sunroof seal issue but I have a whistle that is the actually from the HVAC. Easiest described as the sound when one of your windows isn't quite rolled up all the way at highway speeds. After chasing it down there is an obvious whistle coming from the center dash vents when HVAC is set to footwell only mode. In any blend mode (footwell+dash vents or footwell+defrost) or full on dash or defrost it is whisper quiet. I decided to look here to see if anyone else had the issue or maybe there is just a defect with mine. I saw a reference by @Meteor to it in this related heater thread, so this is a design/manufacturing issue. I stuck my boroscope down the center vents to see what I could see. There is a horizontal cylinder with different fluting that rotates its position depending on the mode. No obvious issue. Talked to my buddy who is a Lexus mechanic. He said that the blower box is a unit, and you have to rip the whole dash off to get to it. I am not in a big hurry to have that happen to a truck with 500 miles on it.

Post back if you have the issue and even better if you have had Toyota look at it. If enough people have this issue I will approach Toyota for them to launch an investigation and maybe get a TSB.

Yup. Even at the low speeds the blower is very loud. I was wondering if I might have an issue with the damper switching between the different modes (def/dash/feet vents). But, I think it might just be poor design.

 

[MrBrownSugar]

Same here on a 2024 1958.

The noise is coming from behind the front vents or behind the middle/central display.
There is even a secondary whistling component mixed with the main sound of air flow.
Here is a recording of what I hear on mine -

Murds, thanks for pointing me to this thread. And cool idea with the boroscope. If you still have it, it will be interesting if you can loop it through the floor vents and see if there is anything obstructing the airflow. Even though it doesn't sound like an obstruction - more like an actuator/door not completing its motion.

Btw, not sure if you have seen this thread on Tundra. Sounds similar. AC/Heater Whistling

 

[Murds]

Same here on a 2024 1958.

The noise is coming from behind the front vents or behind the middle/central display.
There is even a secondary whistling component mixed with the main sound of air flow.
Here is a recording of what I hear on mine -

Murds, thanks for pointing me to this thread. And cool idea with the horoscope. If you still have it, it will be interesting if you can loop it through the floor vents and see if there is anything obstructing the airflow. Even though it doesn't sound like an obstruction - more like an actuator/door not completing its motion.

Btw, not sure if you have seen this thread on Tundra. Sounds similar. AC/Heater Whistling

I did try and go up through the floor vents. I couldn't get a clean look at anything, too many turns. Best guess is the cylinder is not rotating to the proper spot or they put in small bypass holes for some minimal airflow to the center vents not planning on it sounding like forcing air through a crack. With enough folks reporting it we can go to Toyota and have corporate open a case. This may be one of those problems solved by turning the radio up...

 

[mav]

I have the same issue on a LCL.C. Loud wind noise from the front air vent area only when foot air only mode is selected or when I chose auto (can’t tell what mode auto is putting it in). If I change the air mode to direct air to both feet and anything else (front vents etc) the sound goes away. Sound doesn’t noticeably change when. I manually adjust air level or temperature up or down. But it may be a bit louder when accelerating. I took it in for 5K service and they couldn’t diagnosis and now want to get in the dash but don’t know if they could even get the parts if needed so it could take weeks. Uggh. What should I do? First and only problem with my trail dust LC.

 

[MrBrownSugar]

Yes, the problems is caused by having the air go entirely towards the footwells(down). The way Auto is programmed is that, if it needs to heat up then it points the flow down, and if it needs to cool down it points directly towards the passenger/driver (front). You can try to start decreasing the target temperature and the moment it reaches a level where it doesn't need to heat anymore, the air will get redirected and the noise goes away.

And yes - despite that the noise is triggered by the direction of the airflow it is correlated to the wind strength outside. So if you're driving on the highway the noise keeps going up and down - acting like a wind noise amplifier. I wonder if we should make experiments with the outside vents that are next to the windshield. The more information we provide to the dealerships the more likely they will be able to think of a solution.

On the bright side - once the car warms up the noise goes down even when on Auto. I personally always set it on Auto and then manually change the direction to be down+front. This way all other functionality of Auto is still active (controlling the temperature and the fan RPMs) and I just override the direction. Obviously this is far from ideal and I hope Toyota figure out the root cause.

 

[Murds]

I have the same issue on a LCL.C. Loud wind noise from the front air vent area only when foot air only mode is selected or when I chose auto (can’t tell what mode auto is putting it in). If I change the air mode to direct air to both feet and anything else (front vents etc) the sound goes away. Sound doesn’t noticeably change when. I manually adjust air level or temperature up or down. But it may be a bit louder when accelerating. I took it in for 5K service and they couldn’t diagnosis and now want to get in the dash but don’t know if they could even get the parts if needed so it could take weeks. Uggh. What should I do? First and only problem with my trail dust LC.

Personally I won't let them start tearing down the dash. They are unlikely to fix it and you are going to end up with squeaks and rattles or even a pry mark. I would direct them to this thread and make the point that this issue isn't just your truck. There is an issue in the blower box. I think this issue is bigger than the number of posts here. From what I can tell Auto directs footwell-only when it is pretty cold outside, otherwise it likes to blend (no noise). So our friends in the more temperate climates aren't even in tune with this (yet?).

As you'll see mentioned in other threads in this forum - we are the beta testers and we have found an issue. TBD if it is resolvable. In the mean time it's turn up the radio or manually set the flow to blend.

 

[Bajacruzzer]

Picked up a new LC in October. We had a warm Fall in the NE but now in full heat season. At first I thought I had a door or sunroof seal issue but I have a whistle that is the actually from the HVAC. Easiest described as the sound when one of your windows isn't quite rolled up all the way at highway speeds. After chasing it down there is an obvious whistle coming from the center dash vents when HVAC is set to footwell only mode. In any blend mode (footwell+dash vents or footwell+defrost) or full on dash or defrost it is whisper quiet. I decided to look here to see if anyone else had the issue or maybe there is just a defect with mine. I saw a reference by @Meteor to it in this related heater thread, so this is a design/manufacturing issue. I stuck my boroscope down the center vents to see what I could see. There is a horizontal cylinder with different fluting that rotates its position depending on the mode. No obvious issue. Talked to my buddy who is a Lexus mechanic. He said that the blower box is a unit, and you have to rip the whole dash off to get to it. I am not in a big hurry to have that happen to a truck with 500 miles on it.

Post back if you have the issue and even better if you have had Toyota look at it. If enough people have this issue I will approach Toyota for them to launch an investigation and maybe get a TSB.

Did you replace the cabin filter? This may sound weird, but if you put the filter in upside down they will make a whistling noise. I had this issue on my TRD 4X4 Offroad.

 

[MSINAL]

I did try and go up through the floor vents. I couldn't get a clean look at anything, too many turns. Best guess is the cylinder is not rotating to the proper spot or they put in small bypass holes for some minimal airflow to the center vents not planning on it sounding like forcing air through a crack. With enough folks reporting it we can go to Toyota and have corporate open a case. This may be one of those problems solved by turning the radio up...

Wondering if directing all air flow to floor vents creates over pressure in diverter chamber which bleeds out into other ducts at high velocity (whistle). Could be due to ducts and vents of foot wells being too restrictive. Might be an easy fix - when mine arrives and i still think noise is caused by duct restrictions, i'll volunteer to take a smallish holesaw to foot well duct to prove hypothesis.

 

[Roonie]

I had the dealer diagnose my whistle and they said all the Landcruisers they had on the lot sounded like mine. Really loud! They were not going to do anything.

 

[gourd]

I received the same report from my dealer this afternoon: That's how Land Cruisers sound. There's nothing to fix.

I am unhappy with the result and particularly bothered by the service advisor saying that he could not hear the obvious whistling sound.

 

[Roonie]

I received the same report from my dealer this afternoon: That's how Land Cruisers sound. There's nothing to fix.

I am unhappy with the result and particularly bothered by the service advisor saying that he could not hear the obvious whistling sound.

My service advisor heard it and commented it sounded like someone is brewing tea inside. But said there is nothing they will do because they all sound like that. I was like wow an 85k rig sounds like shit when warming up then.

 

[ultane]

My service advisor heard it and commented it sounded like someone is brewing tea inside. But said there is nothing they will do because they all sound like that. I was like wow an 85k rig sounds like shit when warming up then.

AGREED!!!

 

[gourd]

A tea kettle whistle is a great description of the sound.

I measured the HVAC mode sound levels with the fan on high using the
free NIOSH Sound Level Meter application. The footwell-only mode is approximately 67 decibels. All other modes are approximately 60 decibels.

This objective measurement may be something that I can use to drive a resolution with the dealer or Toyota. It will be great if other people can chime in with how their LC's measure using NIOSH or any other sound level application. If I have time to go this weekend, I'll ask the dealer where I purchased the LC if I can measure the LCs on their lot.

 

[Meteor]

On the bright side - once the car warms up the noise goes down even when on Auto. I personally always set it on Auto and then manually change the direction to be down+front. This way all other functionality of Auto is still active (controlling the temperature and the fan RPMs) and I just override the direction. Obviously this is far from ideal and I hope Toyota figure out the root cause.

I've been doing exactly this while we're in cold weather. This is a much simpler fix/alternative than bringing it to the dealership, wasting time with them, potentially having them open the dash, not fixing it, squeaks and rattles from opening the dash thereafter... Don't get me wrong, I'm not happy about it, but it's a non-issue, all things considered.

 

[gourd]

I called Toyota again. The person I spoke to said that the whistling is not a known problem. If your HVAC whistles, please call Toyota at 800-331-4331 to help get this on their radar.

 

[ZNFRNO]

Same whistling and noise with mine too.