The tatty areas seem to have a primer under the silver paint.
Whilst doing a service (77,000 now) recently I saw that the mating face is heavily pitted, which I imagine is the Magnesium element of the alloy corroding faster than the relatively stable Aluminium.
Plan will be to whip off the two covers and clean them up by hand, then prime and paint with rattle cans.
Thought I'd whip out the fixing screws and seals; plug tunnel seals; and the oil filler, then to rub down the affected surfaces using well-oiled wet-or-dry paper on a flat surface, then clean off oil with solvent and immediately spray on an etching primer (before the Mg corrodes again) and paint.
Anyone else done this by hand can offer advice?
