Too much sun here... if I was to wash any of our fleet (all 3 are black, and it looks like a funeral directors here at times), then they would just end up looking like a hazy hologram as the heat causes the paint to looked scratched to ****.
Maybe I will do it in the dark as the next 2 weeks are forecast to be the same.
I’ve never had any issues washing engine bay. Modern engines are sealed well.
back in the days with the older engines water would affect the distributer/plugs/coils etc but my 2004 Maserati is fine. Just one thing. Never point the pressure washer nozzle close up to any components you will damage something. But a general rinse and scrub is fine.
imo, never wash and/or hose an engine bay, if you want to detail,then use small paint brushes and degreaser if that bad on older oily engine bays if you really must, remember the days when garages used to steam clean engine bays