So it's ok for the coil packs to get wet? I am wanting to scrub clean my 2010 Police Charger with low pressure water and soap. Figured I'd shroud the alternator and computer with aluminum foil, but am weary about getting coil packs wet.
Just cleaned my 300C engine compartment, the way I've done it for decades.
I went to one of those coin-operated car washes, popped off the engine cover, and wrapped the exposed electronics with plastic and a little painter's tape (not too much, degreaser turns it into a gooey mess).
I sprayed everything down with foaming engine cleaner (either Gunk or Supertech, the Walmart house brand), let that sit for a few minutes then hit it with foaming spray from the hose (if it's a dual-pressure system, use the low pressure around your intake and electronics), then finally a clear water rinse with low pressure.
If you don't have much in the way of grease or oil deposits on the engine and it's just a dirt-and-dust cleanup, foaming spray and a clear rinse should do the job just fine.