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Just as I resolved the annoying brake squeal, another sound comes up. This whirring sound coming from the dash/vents drones on for 5-10 mins at a time before going away. Sound starts upon startup, stays on during idle or driving, stays on for some time after turning off the engine. Not sure if it's related, just once recently my engine revs were hanging high after I stabbed the throttle while changing lanes.
Please see attached, very short clip. You might have to turn up your speakers to hear the whirring sound.
Make a longer clip and at night when it's generally much quieter outside. On my 2013 my nav unit had a faulty fan that was making a clicking sound that you could hear clearly at night and when you put your ear to the cd slot. From your description it doesn't sound like the same issue.
Sure your not just hearing the nav drive spinning? It's a laptop size disk drive.
Beginning at 8 seconds (of the 12 second long sound clip) it sounds to me like a very small motor being energized and coming under load as it performs its duty.
My guess is that this sound is coming from one of the air (damper door) vent servo motors that are needed to blend hot or cold air and to direct the airflow to a particular vent. These small servo motors are electrically signaled soon after ignition start when the sophisticated A/C system determines what airflow and vents need to be used, however the A/C system continually makes adjustments based on many inputs to its system. If I am correct, this sound you are hearing is of no concern and typical of its proper operation.
Below is a picture of a typical servo motor, which is responsible for rotating plastic gears to-and-fro within the unit, which is ultimately connected to one of the A/C system's air (damper door) vents. When the servo motor is signaled to operate (by receiving a positive or negative voltage) the tiny motor is put under a significant load as it opens or closes a damper door. I believe this sound you are hearing is the servo motor, and the change in tone at the 8 second mark of your sound clip is the servo unit actually moving the damper door.
As an aside, the plastic gears that the servo motor rotates can break teeth due to the damper door getting stuck/frozen or lodged, which usually happens during very cold conditions. When a gear has broken teeth there is usually a clicking or ratcheting sound as one plastic gear tries to engage with another plastic gear, but can't due to missing teeth on the circumference one of the other gears. As the gears try to engage there is a clicking or ratcheting sound that is heard. You do not want this (broken gear teeth) to happen because it is a pain in the *** to replace the servo motor unit in most cars and it can be very labor intensive. I think the price of a new servo unit is around $150 to $200. I've heard that some labor (only) estimates have been as high as $800 just to replace the unit in some Lexus vehicles. I feel sure that in some model vehicles it is fairly easy o replace and others are a lot more labor intensive to replace.
Thank you for such a thorough explanation! Now that you mention it, there may be a correlation with this phenomenon and lower temps. While I’m glad this doesn’t point to an engine/drivetrain issue, it’s hard not to worry about something that has never happened before in 4.5 years of ownership. I guess I’ll wait and see as spring approaches!
That said, I’d be happy to hear from others in case there are alternative hypotheses.
What is the round thingy to the left of the clock? My GS does not have that.
The round thing is a magnet mount clipped onto the vent. I got it from Logitech a few years ago. It’s not that strong a magnet so I have to attach the metal plate outside my phone case. It was also more expensive ($12?) than a generic version but looks nicer and blends in better.
Thank you for such a thorough explanation! Now that you mention it, there may be a correlation with this phenomenon and lower temps. While I’m glad this doesn’t point to an engine/drivetrain issue, it’s hard not to worry about something that has never happened before in 4.5 years of ownership. I guess I’ll wait and see as spring approaches!
That said, I’d be happy to hear from others in case there are alternative hypotheses.
Again, thank you!
You are very welcome. As I said, it is my best guess of what the noise you're hearing is about.
As you change the A/C system's temperature up or down you may cause a servo unit to respond. Servo units seem to be activated soon after ignition engine startup and also when the outside temperature is about the same as the vehicle's inside temperature, which can cause the system to switch back-and-forth between upper vents and floor vents.
The round thing is a magnet mount clipped onto the vent. I got it from Logitech a few years ago. It’s not that strong a magnet so I have to attach the metal plate outside my phone case. It was also more expensive ($12?) than a generic version but looks nicer and blends in better.
I think that round thingy is making the noise. My GS does not have one, and it makes no such noise. Have you tried removing it (the thingy)?
03-02-18, 09:11 AM
What's this whirring sound from dash?
