A very common problem on the Z32 is that the dashboard around the defroster comes loose and peels up.

So how do we fix this ?

Remove the plastic defroster guide by using a flat screwdriver

Put some very strong adhesive (preferably 2 component epoxy) in the opening (white arrow)

NOTE: Before doing this, you might want to cover the rest of the dashboard with old papers, 
so incase you spill some epoxy/adhesive your dashboard isn't ruined.

(Since it's a difficult area to get to because of the windscreen, using a small 
paintbrush to apply the adhesive, makes things a little bit easier)

Once the adhesive has been applied use some blocks of wood to firmly press everything together 

after letting the adhesive/epoxy dry for a few hours...