All that, only to find out my battery fan filter is perfectly clean after 6 years of owning the car. Oh well, better safe than sorry.
Did you figure out anything in the process, make it easier next time? Or it’s just your typical “diabolical fastener”…
I was turning the Phillips head screw counterclockwise while simultaneously prying the washer up with a flat head screwdriver, but it wasn't budging. Then I tried the brute force method with a couple of different pairs of pliers, but it wasn't easy to get a good grip, as can be seen by the damage I did to the hole in the panel. Diabolical is a good description. I guess I will try to pick up another clip from the dealer, but I'm tempted to just leave it unclipped. The panel stays in place quite well anyway.
Very simply, I would have drilled a small hole with a reverse counterclockwise drill bet and released it with one of these fluted screw extractors. 5Pcs Screw Extractor, Straight Fluted Screw Extractor Set, Broken Damaged Bolt Easy Out Removal Tool Square Type
I'll keep that in mind for future issues, but for a plastic screw it seems like overkill. The screw was turning, but possibly the ribs on the underside of the washer had become too brittle to bend inward. In fact, it was quite a job to pull and twist on the head of the washer until it separated from the bottom part, which (I guess) fell into the crevice next to the battery.
