i was really tempted to steam clean my engine bay when i first got my car. then i found out about the harness problems and held off. caught up with me anyway and had to have the harness done but i'm still not going to steam clean it. i wipe the grime with quick-n-brite (as seen on tv), work it in as needed then sponge it off. i use simple green on other parts and rinse with water...
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"