The engine for the most part is water/resistant . I actually used the super suds feature at car wash and filled complete engine bay full of suds then used low pressure to rinse off. You try at you own risk, it worked for me on 2 srt6:s. I would probably limit amount of water pressure where the cpu is located in plastic box on pass side near/at firewall. also cover alternator with plastic bag. Do this when engine is cool. I think simple green with low water pressure would be ok. Then i take some cdc engine detailer and spray an wipe down where necessary.