I want to detail the engine of the 280. As you can see, after removing the plastic engine cover, the top is filthy and covered in dust. 
What do you suggest I use to clean this? Would a light spray of diluted G101 on this area, agitated with an EZ brush and then washed off with a light water spray be safe, or is that a complete no-no?  If so is there an alternative or so I shove the cover back on and clean around it? 
the engine and bay are not too bad however, the alloy parts, such as the engine mounts, alternator engine body etc. are all badly pitted and corroded. Never seen the like. Certainly the CR170 was no where near this bad and that was four years older. So that’s one thing I do want to rectify so suggestions please! As always, any help / suggestions most welcome. 

Edited 2 June, 20206 yr by numskull

Plenty of nooks and crannies there. Can see the pipe work that you’ve cleaned. I would suggest that a light spray is a no no. I have no idea. If your on FB, post a request on Detailing Addicts where there are plenty of guys who are well into this kind of intensity of car cleaning! Impressive work to be seen.