Thumping under floor when AC is on.

fruitcakesa

Top Post Dawg
Joined
Feb 18, 2007
Location
Vermont
TDI
04 jetta 5 spd wagon
This happens only when the fan is set to 4.
On the lower settings it is quiet.
It feels like it comes from the floor area but I know the AC is not anywhere near.
If it matters, the foam has come off the blend doors but I still get cold air from the vents.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Does it happen if you drive in reverse? Yeah, it sounds like a stupid question, but I have an angle...
 

meerschm

Top Post Dawg
Joined
Apr 18, 2009
Location
Fairfax county VA
TDI
2009 Jetta wagon DSG 08/08 205k buyback 1/8/18; replaced with 2017 Golf Wagon 4mo 1.8l CXBB
I want to guess that since you have some foam moving around, that at high speed one of the HVAC doors is being blown against the stop (instead of being quieted and sealed by the foam) and that this vibration is traveling around where you hear it.
 

fruitcakesa

Top Post Dawg
Joined
Feb 18, 2007
Location
Vermont
TDI
04 jetta 5 spd wagon
I want to guess that since you have some foam moving around, that at high speed one of the HVAC doors is being blown against the stop (instead of being quieted and sealed by the foam) and that this vibration is traveling around where you hear it.
I think you have hit it as the foam has/is coming out in large chunks and it is distinctly in the footwell/underdash area.

I have been reading up on the fix it procedure and just need to take the time to tackle it along with all the other jobs the car require on a regular basis:eek:
At least it still blows some cold air at lower fan speeds. Hot summer days.
 
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