Air blower noise when accelerating

[Paul41]

Hi all, bit of a weird one here but hoping that someone has experienced this before and knows what the issue is because I have absolutely no idea how to start trouble shooting it!

I have a 2017 Expy, 3.5 v6 Ecoboost, under heavy acceleration, at about 2500 revs+ I get an air whooshing noise, the noise itself sounds exactly like someone has turned the blower motor up full (imagine the noise of the air blowing out of the vents), as soon as I lift off the gas (or the revs even out) it stops, as though the blower motor is being turned off. When I first heard it, I thought I was having some weird electrical issue that was causing the blower motor to turn up full when accelerating, however I have ruled this out by turning the ac/air system off completely and still getting the same sound, there is no air blowing out of the vents when I can hear the sound. It sounds like it is behind the dashboard, mainly on the driver's side. I have no loss of power and the truck drives great, but the noise is driving me crazy as I don't know what is causing it.

I replaced the water pump recently and only noticed the noise since this has been changed but can't think why changing the water pump would bring this noise on. I don't recall hearing the noise before changing the water pump, but this could just be because the radio/music was masking the sound... possibly.

If anyone can shed any light at all on this, I would be eternally grateful.

 

[S20Workstation4]

I'm almost sure that the problem is that one of the hoses is not connected correctly, and air is leaking past the hose when boost pressure is applied. Check to make sure that there is not an air filter restriction, or one of the plastic clips haven't broke by the inlet side of the air pipes, and its trying to suck it into the system. Changing the water pump may have required the hoses to be removed, which if you removed them, they may not be on correctly.

My 2019 had this problem, this deep blower-type noise that happened under high-boost instances, and it turned out that the hoses weren't on correctly, and boost was leaking past.

- Joseph.

 

[Paul41]

I'm almost sure that the problem is that one of the hoses is not connected correctly, and air is leaking past the hose when boost pressure is applied. Check to make sure that there is not an air filter restriction, or one of the plastic clips haven't broke by the inlet side of the air pipes, and its trying to suck it into the system. Changing the water pump may have required the hoses to be removed, which if you removed them, they may not be on correctly.

My 2019 had this problem, this deep blower-type noise that happened under high-boost instances, and it turned out that the hoses weren't on correctly, and boost was leaking past.

- Joseph.

Thanks for this, and I think you are correct. When I have the window down I can hear the air noise much greater and seems to indicate it is one of the air pipes that I removed when replacing the water pump. I will get back under the hood this weekend and check it over!

 

[Pdipaolo]

Check the recirculating tube to your air intake. It should be connected from the blow-off valve at the bottom of your intercooler to a quick-connect on your air intake…

 

[Paul41]

Thanks for the response!
I checked at the weekend and can confirm it was the air pipe from the turbo to the inter-cooler not situated correctly. I'm guessing it was making sound like the blower motor as the pipe is situated deep down in the engine bay and right next to the firewall.
I've re-situated the pipe and the noise has gone!