Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Sound of air escaping

This site may earn commission on affiliate links.
So, I've noticed this issue lately. When starting to decelerate, I can hear the sound of air escaping from somewhere under the car. It's the same sound that you would hear when the pneumatic doors of a bus opens. After I drive for 15 or 20 minutes, though, it seems to go away.

I emailed Tesla Service - they said that it represents air from the suspension system used to recharge the dehumidifier, but it seems excessive, considering the number of times I hear the noise. There are absolutely no driving issues, and air suspension works fine.

Anyone else experience this?
 
they said that it represents air from the suspension system used to recharge the dehumidifier
I don't know enough to say for sure, but this sounds really weird. Why is there a dehumidifier? I haven't seen that mentioned before. Air Conditioning by its nature pulls moisture out of the air, but it doesn't need a pressurized air source to function. Further, they sell cars without the air suspension. What's the impact of a system that requires pressurized air from a suspension component that doesn't exist?
 
I emailed Tesla Service - they said that it represents air from the suspension system used to recharge the dehumidifier

This sounds like nonsense to me. There is no dedicated dehumidifier in the Model S other than the AC, which shares no interaction with the air suspension. Do air suspension cars come with an added dehumidifier just for the air suspension system? Maybe, I don't know.
 
No, I can definitely hear the usual mechanics behind raising and lowering the suspension. That's not what I'm referring to. This is clearly a blast of air, and sounds just like a bus door opening, or the pneumatic brakes on a truck activating.

This is the reply I got from the service center:
"The air suspension compressor will occasionally release a burst of pressurized air to regenerate the dehumidifier. It is normal operation for the vehicle to make that noise."

 
I had also wondered what that sound was. Thanks for clearing up this mystery!

Over more than a year of driving, my car has made this sound about 3 times, and those occasions were all very rainy days. The first time freaked me out, as it sounded like a large truck was coming up in my blind spot and hitting its brakes. This was definitely a loud blast of air, not the normal gentle sound of the air suspension raising and lowering. I've always assumed it was purging water that got into the air suspension, but was never quite sure.
 
For once the service center tech is absolutely correct. They use air to purge a desiccant to keep the system free of humidity. Here's the patent that describes how it works: Patent US4327936 - Air dehumidifying arrangement for pneumatic vehicle suspension system - Google Patents
Whaaaat? I'm pretty sure that more than half the time they just make stuff up. I find it hilarious that this seemingly-ridiculous statement is the one that's actually true, when so many of the plausible things they say are false. Explains why the air suspension needs a dehumidifier and the coils don't.
 
This makes sense to me. The air suspension has an air compressor. When the air compressor compresses the air it condenses the humidity out of the air. You don't want the water in the air system, because freezing would be a big problem destroying stuff and the potential for corrosion too. So, they need to separate the water from the air, so they use a desiccant. On the equipment I am involved in building, we use a turbo 2000 air dryer, which uses a heated element to keep the system operating below freezing. In our case we have a removable/replaceable desiccant. It appears tesla is extending/regenerating the desiccant (cool!).

I too have heard this on my Tesla. I was very puzzled as to what this was, until I ran across this thread. I brought up the issue to Tesla a couple times, but they thought I was crazy or had no idea what I was talking about, and I couldn't replicate the issue (it seemed to happen randomly). But this thread gives me a much better idea of what is going on.
 
May air suspension is completely silent while raising or lowering, there should be no noise.
What is this silent air suspension you speak of? I can hear mine 15 - 20 feet away outside of the car, and easily inside of the car. Plus I get lovely brake booster chatter thrown in randomly too.

So these noises are not normal? I am not asking in jest.
 
Last edited:
Whaaaat? I'm pretty sure that more than half the time they just make stuff up. I find it hilarious that this seemingly-ridiculous statement is the one that's actually true, when so many of the plausible things they say are false. Explains why the air suspension needs a dehumidifier and the coils don't.

Yes, I think most of those guys have no clue. In this forum alone I've probably heard a hundred different things service has told people that is just total BS!
 
What is this silent air suspension you speak of? I can hear mine 15 - 20 feet away outside of the car, and easily inside of the car. Plus I get lovely brake booster chatter thrown in randomly too.

So these noises are not normal? I am not asking in jest.

I don't hear any compressed air sounds from my suspension ever. Not once. That's what I'm referring to. Sitting inside the vehicle there is no apparent noise from the air suspension while raising or lowering.
 
On every car I've been in you can hear the compressor when it kicks in. Not loud per se, but no mistaking it either. If you are in a relatively dry area, you may never hear the desiccant purge though.
 
On every car I've been in you can hear the compressor when it kicks in. Not loud per se, but no mistaking it either. If you are in a relatively dry area, you may never hear the desiccant purge though.

I live in Arizona so that may be why. Although I had one loaner about 2 years ago that made that loud hydraulic pffft sound several times on the freeway and it scared the bejeezus out of me.
 
I don't hear any compressed air sounds from my suspension ever. Not once. That's what I'm referring to. Sitting inside the vehicle there is no apparent noise from the air suspension while raising or lowering.
Sigh. I've got an appointment at the service center this Friday for a variety of things. Tire pressure sensor warnings off and on, noisy air suspension, brake booster pump noise, car lowers randomly when sitting still and no one in car, and some HVAC issues.

I'm only 90 days into ownership, and it's my second time into service. First was because the passenger airbag sensor failed and the trunk lid was loose. That was 10 days, I wonder what this will be.
 
Sigh. I've got an appointment at the service center this Friday for a variety of things. Tire pressure sensor warnings off and on, noisy air suspension, brake booster pump noise, car lowers randomly when sitting still and no one in car, and some HVAC issues.

I'm only 90 days into ownership, and it's my second time into service. First was because the passenger airbag sensor failed and the trunk lid was loose. That was 10 days, I wonder what this will be.

Was your car a December 2015 delivery?