Well, the window film grille block was still intact and doing its job, but it was starting to loosen a second time, and the latest hot air treatment only seemed to last about one day, so I decided to replace the film with black plastic.
The material was liberated from an expanding portfolio, and I think is some kind of polyethylene, maybe similar to what Craig Vetter is using on his
Aero Helix scooter.
I made a paper template and used scissors mostly to cut the plastic.
I made the plastic in two sections. Here is the first side fastened.
I used zip ties to fasten the plastic, after drilling small holes (inside view):
Here is both sides fastened. The black stock trim piece is used to hold the top portion of the grill block to the front of the grille. So I only used three zip ties on each side along the bottom to secure it. If it starts to come loose, I can add more zip ties later.
Here is the re-blocked grill installed on my Lil' Red Protege:
Here you can see the open area inside and below the Mazda emblem:
The open area (about six inches of open area, I believe) will allow a bit more cooling air into the radiator, although I did not notice any temperature elevation from the window film block.
I may block the sides of the lower grille in the future, so I don't feel the need to fully block this upper grille right now.
Total time: about 2 hours, plus 30 minutes to post here
.