Weird AC Sound from 2018 i3s BEV

[Bluei3s]

So before I start, my car is a 2018 i3s BEV with about 15k miles on it. Of course, I'm 2 months past the 3 year warranty, so there's that....now to get started.

I was driving around today on a normal 75ish degree day and had the AC on low (72ish) and I started to hear a weird sound that almost sounded like the a vent was rubbing against something. It wasn't particularly loud, but it was there. I've started/stopped the car a couple times since and the sound is still there (I just turned it on to check, but otherwise drove with the air off).

I just played with it a bit in the garage and took a few videos which are below. The video makes it sound way more aggressive than it actually is in real life, but it's definitely the right sound. The sound appears to be coming from the vents, and can be heard louder with the frunk open. It also changes volume drastically as the air is turned up and down (as you can see in the video).

Anyone know what this is? I'd prefer not to spend $20k replacing all the coolant lines....

https://vimeo.com/627018033
https://vimeo.com/627019965

 

[alohart]

Assuming that you reside in the U.S., is your warranty only 3 years? Our 2014 BEV had a 4-year warranty. Maybe BMW decreased the warranty length at some point.

 

[Arm]

I've the same car. I don't hear anything out of the ordinary. Plus your car should have 4 year, 50k mile warranty.

 

[Bluei3s]

Ah I think you all are right, sorry about that. I must be thinking of the care plan or whatever that was only 3 years. I haven't been to a dealer since I bought it so I haven't really thought about it!

 

[OLDBMWGUY]

Long shot: Have you checked your front inlet for the condenser? Before I installed a "grill" to protect it, I used to get leaves/debris in there and the leaves could be "sucked" up against the condenser when the A/C/Cooling system was pulling air in. Maybe that might make a noise as you describe.
Also, is it possible that one of the horizontal plastic "vanes" in there that flap up and down for temperature control might be bent/misaligned and responsible?

 

[Bluei3s]

Good question, I basically looked everywhere I could see without taking any parts off. The front inlet looked clear, but I was incredibly surprised by how open it is. I replaced my cabin air filters about 6 months ago and they were pretty clean, so I'm not sure how debris stays out of there.

Did you take the screen off and just stick your arm down the intake pipe? I looked at taking the grate off, but those bolt covers looked like something that would easily snap so I just took it to the dealer for a warranty look instead.

 

[Arm]

Good question, I basically looked everywhere I could see without taking any parts off. The front inlet looked clear, but I was incredibly surprised by how open it is. I replaced my cabin air filters about 6 months ago and they were pretty clean, so I'm not sure how debris stays out of there.

Did you take the screen off and just stick your arm down the intake pipe? I looked at taking the grate off, but those bolt covers looked like something that would easily snap so I just took it to the dealer for a warranty look instead.

What sound are you describing? From your videos, I honestly don't hear anything out of the ordinary. Are you talking about a squeaking type sound? Does it do it while the system is running? When you turn it off? When you turn it on? Etc?

I had my heater core and vent assembly replaced on a previous i3s (2019) because at start-up, I would hear a squeaking sound that coincided with the vent flaps internally moving to a different position or the fan spooling up. My 2018 i3s has a very subtle squeak coming on as well so it may need the same work done..hopefully prior to warranty end. But I didn't hear anything like that in your videos.

 

[Bluei3s]

It honestly sounds like one of those little foam fans when you stick your finger in it. That's why I almost think it's a leaf or something stuck in the system somewhere.

The volume/severity is directly correlated to the speed of the fan, so if I turn it off, it goes away, but if I turn it up to Max it gets a lot louder (especially in the frunk area).

I'm definitely used to all the songs of the car (I bought it new), but this is absolutely a new one that both me and my wife got nervous about. The service tech also noticed it pretty quickly.

 

[Arm]

It honestly sounds like one of those little foam fans when you stick your finger in it. That's why I almost think it's a leaf or something stuck in the system somewhere.

The volume/severity is directly correlated to the speed of the fan, so if I turn it off, it goes away, but if I turn it up to Max it gets a lot louder (especially in the frunk area).

I'm definitely used to all the songs of the car (I bought it new), but this is absolutely a new one that both me and my wife got nervous about. The service tech also noticed it pretty quickly.

Interesting...I didn't hear anything like that in your videos.

 

[Bluei3s]

Yeah the sound of the airflow almost drowns it out using a phone mic. Someone just sent me the below link which is the exact same sound. Given how similar it sounds, I'd guess that it's a bad fan bearing. I'll wait for the dealer (obviously), but now I feel better thinking it's not a leaf!

https://m.youtube.com/watch?v=X1L2b2CDkCc

 

[Arm]

That bearing fan would definitely be heard even over the airflow. That's really loud.

 

[frictioncircle]

It definitely sounds like either some debris caught in the fan or a bearing issue.

I would think that if debris (like a leaf) was caught in the fan, the debris wouldn't last long with constant abuse from the blades.

A failing bearing seems much more likely. Please share what you hear back from your dealer!

 

[Bluei3s]

Got the car back from the dealer today. Turns out it was a leaf in the fan, however the way the service tech explained it is that the fan is more like a dyson fan in that it's cylindrical with the fan around the outside. I guess that's why a leaf doesn't get shredded and just stays in there and makes a constant noise.

I also can't quite figure out how a leaf would get past the filters, but it sounds like it happens, so I may look into a very fine mesh to put in the intake under the hood to keep large debris from even getting to the filters.

They also tried to charge me over $700 dollars to remove some leaves....so there's that.

 

[frictioncircle]

Thanks for the update, Bluei3s, glad you're back in action!

 

[OLDBMWGUY]

Even in Hawaii I have found leaves in my A/C inlet, some of which made slight noise. I bought a conversion kit from Amazon that allows me to use my Shop Vac to use a very small, long thin, nozzle that enables me to reach through the inlet guards and the "fins" (when raised in the open position). I used that method to vacuum out any leaves stuck against the condenser. But it got to be a pain to do that at least monthly or when I heard a noise.

Then, based on the scary reports of the A/C problems (rock damage to the condenser with subsequent costly repairs) and following the always invaluable advice from "AlohaArt", I ordered some black flexible wire mesh (1/2 inch openings) from Amazon, measured and cut it to fit over the "grill", and secured it with some flexible black twist ties (4 hours work). It is not really that visible at all and keeps out the leaves as well as rocks/stones.

I kept a careful record of the battery temps during the last 9 months of the "mesh" usage and even in the summer time with high heat, the "mesh" does not affect the temperature (or A/C temp) so enough air is certainly passing through to cool the condenser.

I did spend 10 minutes removing it prior to taking it to the dealer for the "2 year" service last month just in case they might look askance at the "mesh" and claim some sort of "after market" alteration on my part. Then it took 10 minutes to re-attach it once service was completed. Cheap insurance.