The true automobile enthusiast have always taken the longer more detailed route in the care of his pride and joy. However, do you honestly believe that a business or service department that handles hundreds of cars a week and has a two week plus appointment backlog does the same. Every shop I've worked for , managed or visited fires up the steam cleaner or pressure washer and has at it when it comes to cleaning the engine compartment and undercarraige. Care is taken not to saturate any of the electronic components even though they are sealed against moisture intrusion. Remember. These components are exposed to the elements of vastly different climates and driving conditions around the world. How else would your engine compartment get so dirty in the first place.