HVAC Noise...

[pacificoflyr]

Alright, next up for the Gremlins....anyone have a high/medium pitched tone on fan level two? I brought it up and the dealer said the tech agreed the blower motor needs to be changed out. Swapped it out.......................and the noise is still there. I will attempt to record it with my phone but it might not be that great.

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[jac04]

....anyone have a high/medium pitched tone on fan level two?

Almost a year late to the game here, but I just found this post.

Yes, I noticed an audible tone from my fan. For me, the tone seems most noticeable on level 1 or 2 with airflow set to the floor. Now, when I say noticeable, I mean that I can hear it with the radio turned way down and usually when stopped (so no road / wind noise). But I didn't let that stop me from trying to fix it.

I removed the blower unit and confirmed that the noise is not coming from the blower motor itself. The noise appears to be airflow related.

When I went to re-install the blower, I left it 'hanging' with the 3 mounting screws just started. This left a gap between the blower unit and the housing. When I turned on the fan the noise was GONE. With the fan running, I pushed it back up into position, and the noise instantly returned. When I let it back down, the noise disappeared.

So, it appears that the noise is the result of either the position of the blower unit in the housing, or the way the airflow reacts as it exits the fan and enters the housing (or a combination of both).

Knowing that, here is what I tried:

1) I made a 1/4"-3/8" thick foam gasket to go between the 2 parts, then re-installed the blower unit. I put 1/4" thick spacers at the 3 screw locations. The noise seemed slightly better, but not by much. Too bad, I was really hoping that this setup was going to work.

2) I taped off the top 1/2" of the squirrel-cage fan, but it seemed to have no impact on noise.

3) I went back to 1), but eliminated the foam gasket. This greatly reduces the noise, but allows some air to escape from the gap between the blower unit and the housing. That's the way I have it for now, but I don't like the uncontrolled airflow. It allows air from outside to be discharged directly into the cabin before going through the HVAC system

Future plans:
I'm going to re-visit 2). I think this strategy might work, but I just need to find what area of the fan to restrict the flow from. I think it may be the bottom instead of the top.

 

[pacificoflyr]

Thanks for your info! I took mine and they changed the blower motor, it was fine for a week then the noise is back, only on level 2 and on any position for air flow. Back I go to the dealer.

 

[SquirrelNuts]

Wait... you guys can actually hear your fan above all the wind noise and hum from your tires?

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