Good Afternoon Evros,The opposite side is entirely flush aside from some corrosion (admittedly, maybe severe pitting in my case) but well inside the o-ring internal perimeter.
Mahle is the OEM supplier for this one I can confirm.
Andy, is there any chance for you to check the new housing for flatness with a straight edge maybe?
Evros
Sorry I missed this.
Just checked with old steel rule and which ever direction I chose it looks flat.
Andy