[Solved] I've Developed a Whistle in the Center AC Vents

After a brutal 50-mile off-road drive in SE Utah my truck now whistles when I turn the AC fan on high and direct all the air to the top vents. Sounds like a leak around the two center vents but I'd like to be sure before I remove stuff to fix it. The truck is 20+ years old... Any suggestions?

 

Can you post a recording?

 

Make sure all the vents are fully open. I had the same whistle but I found out that the passenger vent near the door was partially closed, causing the whistle.

 

If I remember correctly isnt there a foam strip that seals the center vents to the ducting? If so, the foam could be all gone and the whistle is from the air escaping around the joint.

 

I had a whistle noise once and it was from the fan motor,

 

this. Check this first. Does it change pitch or go away depending on the fan speed? Look there first then, and give it a little oil if it is indeed the culprit.

 

It sounds like somebody learning to whistle thru his teeth, or trying to whistle when one tooth is missing

The whistle wants to start when the fan is one step below max, but it doesn't quite make it. It starts when the fan is turned up to max. Then it wavers in pitch a little. I'm sure I'll find something I can fix behind the center louvres, just don't quite know what.

Sorry, no audio.

 

You can also blow compressed air into the vents to clear away dust and any restrictions. Turn on fan while doing this to clear any debris. (wear safety goggles) Also blow into the cowl vent under windshield wipers.

 

you need to oil the blower motor.

 

Huh. First I've heard of this. How do you do it exactly?

 

I know exactly the sound you’re talking about. In my case it only happens when I have the center vent flow selector not fully closed.

Check your vents, and your blend door.

 

Just remove the blower motor and oil the center part that spins, basically the axis part near the bottom of the unit

 

Just teach it the words...

 

Same exact thing for mine

 

The title of this post says SOLVED but the solution isn't documented. What was your fix @skeezix?

I have the same whistle when running max air flow through the vents.

 

Post 6 & 12 explains it

 

Has the whistle come back after you oiled the blower motor?

 

So a member has time to change the title of his thread, stating "SOLVED" but does not take the time to inform his fellow members what the solution was. Who does this?

 

Only an idiot...

Usually I'm pretty good at documenting fixes to my problems but I sure missed the boat on this one. Or maybe 'cause it fixed itself??? I don't recall doing anything to fix it other than removing and reinstalling the motor.

If it happens again, I'll try oiling the motor like has been suggested.

 

oiling the blower only puta. bandaid on the issue, which is normally wear on the pinion or bearings. Blower motors are cheap. If the sound comes back just install a new motor.

Thanks for returning!