[vwBeetledriver]

remove and install new insulation

Hey I actually have this problem
and noticed a bit of difference from removing the upper dash, where the cabin filter is.
I removed the two upper dash pieces. anyone can do this on their own. Just be wary of the screws.
When you remove them, you will have to literally rip and pull out that grey insulation. it reeks.
Replace it with the new insulation with the foil on one side. I doubled up on the them under each one.
I had to be creative and cut two pieces for each of the dashes as one piece wont fit in.

Since I have done this. I have noticed a diff. But then again it's now chilly. I did test it by driving for a long time and turning up the heat. Way better.

I will notice more in the summer I suppose.

Good luck

 

[vwBeetledriver]

hey folks figured it out for sure
it's the sound deadner material underneath the floor carpet of your car.
go to any stereo/car audio place and they will pull back the carpet and show you the sound deadener stuf.
REEKS it stinks sooo bad.
you will want to replace it.
Kind of expensive but worth it.
just do under the carpet.
there is another lay of that stuf inside the dash up against the firewall. not worth doing it unless you have unlimited sums of monies.

 

[vwBeetledriver]

update

Had the underlay under the carpet removed and replaced with Silent Coat 2mm and Silent Coat foam and put the original carpet back on. I did clean the back .
the stench is pretty much gone! I will probably have the carpets shampooed as the stench from the underlay really did soak in a little bit into the carpet. But the smell is considerably gone.

There is additional material right inside the dash area. But I am not willing to pay someone for two to three days and in the 4 digit price to get the job done. So far so good though