John, first off in most localities I have visited this is illegal.  The run off is a pollutant !  Use a Pressure washer at your home and make sure the run off goes somewhere nice, good luck with that !  I do this all the time here at my shop out on my gravel drive in front, gravel catches most of the grease.  As far as what needs to be protected, nothing, if all is as it was designed to be everything in the engine compartment is water proof and not affected by water.  Always start the engine immediately afterward to see "if" it starts and to warm up the engine to dry it off.  If the engine does not start then you need to find and fix the problem.  You can use any one of the numerous engine degreasers available at your FLAPS.  Afterwards, I Krown oil the entire engine compartment, this does two things, loosens crusty stuff the degreaser did not get at so the next time you pressure wash, it will get cleaner, and it protects all the components, rust and corrosion inhibitor for metal parts and adds life to rubber and plastic components.  

On 2013-06-21, at 1:34 PM, Automatic digest processor <LISTSERV@GERRY.VANAGON.COM> wrote:

> I need to degrease my engine and was thinking of taking it to one of
> those car wash places with the pressure wands. Just wondering what I
> need to protect from the wash.

Cheers,    

Frank Condelli
Almonte, Ontario, Canada
'87 VW Westy, '00 Kawasaki 250 Sherpa, "98 Ducati 750 Monster & Lionel Trains (Collection for sale)
Frank Condelli & Associates - Vanagon/Vanagon Westfalia Service in the Ottawa Valley
BusFusion a VW Camper camping event, Almonte, ON, June 06 ~ 09, 2013