You gotta be very careful with free flowing water on the hi tech engines with so many sensors/electricals, so from my side its a BIG NO. Although they are insulated to be water proof but if something is not and you end up with it giving up, it can turn out be very messy/expensive to trouble shoot the issue. So better be safe than sorry.
Having said that, international detailer do detail engine bays of such advanced cars using :
- a steamer for engine bay cleaning (I've seen Ahmad Bhai do that to even prius).
- tornado cleaner (attached to an air compressor)
- If you dont have the steamer, then warm up the engine half way through that its warm but easily touchable and then use the degreaser/APC based cleanup with that in a spray bottle and a detailing brush for agitating the greasy/dirty areas and instantly wiping it away with an MF. Be careful with a strong engine degreaser as those aren't againt meant to be used for these hi tech cars engine that has several components materical type from pastic, aluminium, magnesium etc. Safe bet is to spray the APC on the towel and use that to
In any of the above cases, make sure you UNPLUG the battery and to dry properly and not leave any water/liquid. Ofcourse dress it well as most of these hi tech engines have a large plastic trim so that looks great.
I hope this helps and you can get loads of forum posts on international forums about the DOs and DONTs. Also For practical advise, I would ask @ahmad_yar to fill in details from his practical experience with such cars.
