whistle noise with blower fan

[spderjhn]

My blower motor on the ac whistles louder and louder as fan speed increases. Anybody know what causes this? or better yet has fixed it

[Tarheel_6.4L]

The last time I had a whistle, it turned out to be a hole in my intercooler.

[allevil]

I thought my Blower Motor had a Whistle to it too. Like the last couple speeds.

Turned out, I had the Dash Vents Closed on the Passenger Side.

I only use the Driver's side when I'm alone.

Opened them Up and the Noise went away.

Try it and see. Hope it helps.

[spderjhn]

been through the whole vent closed thing. It is still doing the same thing that increases when fan speed increases

[jrod80]

I noticed a whistle in mine and it was because I took the rear vents out from behind the back seat and dynomated over the hole. My subs were making them rattle. Without the rear cab vents it creates pressure causing the whistle. As soon as I cracked a window or the rear slider it went away. I need to poke some holes in the dynomat or something I guess. lol

[spderjhn]

learned something new about my whistle. It only whistles with heater on. if you turn down the temperature to 70 or so whistle goes away. It doesn't matter which vent is open floor dash defrost still whistles ....help?

[53 willy]

I take it this is on a truck with elec climate control. I just took a heater box apart today from a lariat, The only thing I can think of would be that the blend door isnt closing tight on the cold side. When you turn the heat up it closes the door to the cold side. I wonder if the gasket around the door has came off or ripped so it doesnt seal tight. Has it always done this? If its under warranty I wouldnt recommend doing it yourself. You have to take the whole dash out, prob 1-2 hrs, then take the heater box apart which is melted together at the factory, it has provisions to be screwed back together after being taken apart but you would have to get screws. When its cold out see if the temp that it stops whistling at changes from when its warm out. It has a sensor for the intake air so it knows where to have the blend door set to get a set outlet temp. Also try changing pass and driver temp settings If one temp can be hotter than the other then Im sure this is what it is.