Looks like he switched the covers, so its on the back of the driver side cover.

Mine also melted due to the proximity to the turbo, so I bought a metal one off ebay.

 

So you removed the fill neck. How difficult it is to fill without the neck while the turbo is installed?

Actually, it's the fill neck that partially melt not the cap. I have plastic vented fill cap for fresh air as part of my RX dual valve catch can. It's just a stock cap drilled and fitted with filter and check valve.

 

Just unscrew the neck and then screw the filler cap back into the valve cover.

 

I use a long funnel, so not hard. My plastic cap was melted so I got the metal one. My turbo also sits further forward and closer to the engine than most, so the exhaust housing would be touching the fill neck.