Modern car engines are easy to clean. Almost every OBD-II car built after 1996 has insulated electrical connectors and sealed air systems that keep dirt and water from ruining the engine. Unless there’s something broken or missing, detailers can usually hose down, degrease, and scrub engines and engine bays without any issues.
Older cars can pose more of a problem. This 1969 Chevrolet Camaro is typical of mid-century muscle cars, as the engine has exposed electronic ignition systems, air filters, carburetors, pulleys, and other moving parts. But with a couple plastic bags and some other detailing tricks, the Detail Garage crew prepare and detail the entire engine without any issue from the water or cleaners.
Isolate any exposed air and electrical parts with plastic bags and tape where needed. Rinse away loose dirt and debris, then spray the engine bay down with diluted degreaser to break down oil, grease, and grime. Try Chemical Guys AllClean+ citrus-based all purpose cleaner and degreaser. Dilute 5:1 for tough cleaning power on filthy engines without damaging any sensitive surfaces.
Finish by air-drying with a blower or microfiber towels, then dressing rubber and plastic parts with a spray dressing like Black On Black dressing. The refined oil-based formula penetrates deep into plastics and rubber to restore a like-new look on faded hoses, covers, lines, connectors, and cowls.