Crazy noise coming from the dash... need help diagnosing

So I broke my car out of storage this weekend since the temps in my area were going to be in the 50-60s. I set out to meet a family member for dinner about an hour away and noticed when traveling at highway speeds (70-80mph) that I was getting the crazy noise from what I can tell is deep in my dash. I have never heard this before and there seems to be no no rhyme or reason for when it starts or stops (read that as it doesn't matter if I speed up or slow down in that speed range it will sometimes go or not). Almost all the way down to my dinner meeting I could hear this even over the radio, but then on my way back I heard nothing 3/4 of the trip back and then it decided to start again.

Anyone have any idea what this could be?

Here's a few videos that I took on my way home once it started.

<iframe width="560" height="315" src="https://www.youtube.com/embed/XaKwaqbFdtw" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/tFXbsbT7OFw" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/sSM7Rk7cpUI" frameborder="0" allowfullscreen></iframe>

I will add one last thing, and I don't think this matters, but maybe... Briank just rebuilt my climate control this winter after losing the center console fan for the past year... obviously now it works again but the noise doesn't seem connected to the HVAC fan at all....

After watching the videos it does seem like it may be tied to speed... I can hear the rattling get worse as I hit the gas.

If it is tied to vehicle speed, I would first think wind/air - look under car, in suspension and under hood to see if you picked up anything.

silver2002 said:

If it is tied to vehicle speed, I would first think wind/air - look under car, in suspension and under hood to see if you picked up anything.

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I've been all up under the front and do not see anything out of the ordinary. I need to check in the wheel wells behind the liners when I get a chance yet.

Sounds like it could be the ABS unit.

Needs to get exercised and flushed.

I like the ABS idea, good call B2finity. Anyway to easily and temporarily disable it to see if that makes the difference at speed?
Before flush and exercise?

silver2002 said:

I like the ABS idea, good call B2finity. Anyway to easily and temporarily disable it to see if that makes the difference at speed?
Before flush and exercise?

Click to expand...

I just had the abs unit tore down and rebuilt with the seal kit sold on this site. I can tell you it's not the same sound.

Ok, next ideas:
1) check radiator fan [ also where it might hit shroud ] - it typically only comes on when engine is warmed up - see if shroud is loose or if you can make it hit the blades with a little pressure.
2) Test with climate control "off" [ push off button] - blower is always running unless it is "off"
3) I've used a small digital recording device with a mic on long cable in the past and it worked. Move it all around cabin methodically- and say in the recording exactly where you are placing it - like right foot well, left foot well, defrost right and listen later for where sound is loudest. You can even put it under hood near spare tire for a run. Pic of mic in lower right.
4) there are also fans in front of tires behind liner for a/c, I forget if it's one or two fans.

Is it possibly one of the actuators for the CCU air direction flaps?
When you hear it again, try cycling through the air direction modes to see if it stops.

NSXGB said:

Is it possibly one of the actuators for the CCU air direction flaps?
When you hear it again, try cycling through the air direction modes to see if it stops.

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I'll do that. My gut thinks it might be something in that area... It may be another month before I can get the car back out of storage and put insurance on it again though.

NSXGB said:

Is it possibly one of the actuators for the CCU air direction flaps?
When you hear it again, try cycling through the air direction modes to see if it stops.

Click to expand...

I agree that this is a possibility. Particularly the flap for the fresh air intake at the base of the windshield which could be influenced by the air pressure at the base of the windshield and therefor be speed sensitive..

As a first test, at rest, cycle the CCU through its function test and listen for any abnormal noises. Listen for anything that sounds like there might be a problem with the actuator mechanism. If that does not give any results, then do as NXGB suggests. In particular, under the same conditions where the noise previously occurred try cycling between the fresh air and recirc modes.