[devlmaycry]

Okay, just got a new to me 2014 435i xdrive. Everything seemed fine initially, but I just over the last couple days have noticed I have this super annoying ocean wave/beach sound coming from the center of the dash. Has anyone experienced this before? It sounds like a fan in the middle of the dash near the defrost vents cycling approx every 3 seconds. When the HVAC is off the noise is completely gone.

Googling it sounds like it could be related to the NBT cooling fan possibly, but I'm not sure. When the AC is on the noise starts and when it's off it goes away. Seems like it's right underneath the center speaker in the dash.

Adjusting the hvac fan speed doesn't change or affect the sound in anyway either.

Thanks for any help!

[im_an_alien]

Do you have the relaxation package 7SP? Ocean sounds are supposed to be calming..

[im_an_alien]

You may also need to have your system purged for air...

[devlmaycry]

Originally Posted by im_an_alien

You may also need to have your system purged for air...

What would be happening involving the HVAC that would cause that? It's not a rapid cycling compressor like one with a low or over charge. I've got manifold gauges and a vacuum pump. I'll check pressures later today or tomorrow. Though the AC blows cold and doesn't seem to ever get warm.

The sound seems like a fan and is dead center of the dash. Seems like it's right under the center dash speaker/defroster vents and has more of a fan noise. I've read there's possibly a cooling fan for the idrives stuff, but havent tracked down and FSM to check all the parts in the dash there. It sounds like when my RTX 2080 starts getting hot lol

[im_an_alien]

Originally Posted by devlmaycry

What would be happening involving the HVAC that would cause that? It's not a rapid cycling compressor like one with a low or over charge. I've got manifold gauges and a vacuum pump. I'll check pressures later today or tomorrow. Though the AC blows cold and doesn't seem to ever get warm.

The sound seems like a fan and is dead center of the dash. Seems like it's right under the center dash speaker/defroster vents and has more of a fan noise. I've read there's possibly a cooling fan for the idrives stuff, but havent tracked down and FSM to check all the parts in the dash there. It sounds like when my RTX 2080 starts getting hot lol

You probably have air in the core... Did you have any work done recently on the cooling system, like a thermostat change?

[devlmaycry]

Originally Posted by im_an_alien

You probably have air in the core... Did you have any work done recently on the cooling system, like a thermostat change?

Not that I know of, I just took ownership of it a few days ago. Didn't notice anything on the drive, but pretty confident it's been there. Running the coolant purge cycle on my lunch.

The AC compressor looks relatively new. I'll check the pressures later when I get home.

[devlmaycry]

[devlmaycry]

Ran the air purge cycle twice for the coolant system on lunch, it's still making the sound though.

[devlmaycry]

Originally Posted by im_an_alien

You probably have air in the core... Did you have any work done recently on the cooling system, like a thermostat change?

Tentatively fixed.

Evacuating the AC, vacuuming it out, checking for leak down, and recharging the system fixed the noise.