Is it safe?

Can you spray in the engine bay? I know you shouldn't for too long but it's pretty dirty under das hood

 

If you MUST then only use a garden hose. Make sure your oil dipstick is tight and cover any sensitive electrical areas.

 

I've cleaned a lot of engine bays over the years without any issue..Never covered anything or really avoided anything in particular. Common sense goes a long way, I am not saying spray water directly into your intake or purposely excessively hose down electrical stuff but I don't think anyone needs to be overly paranoid either. There is always some risk I guess of water getting into something it shouldn't, but the engine bay isnt exactly weather tight from the factory, the stuff can get wet.. I also use a leaf blower to blow it off after.. Heres a shot of my old STis engine bay, super clean...Hosed it down all the time..

 

https://youtu.be/PRSoRkM8GcM