I have always had great luck using the engine clean function at a high-pressure do-it-yourself car wash on engine comppatments and always wanted to take the Viper, but the engine is so hot by the time you drive to the car wash it would be insanity to be spraying water on the engine. A couple of weeks ago I dropped my car off at an independent service center to have the AC charged after I replace the six o-rings in the system. The guys finished the car about 10:30 am. Just so happens there is a do-it-yourself high pressure facility right next store, so I pciked the car up about 3:00 after it had sat for a good four hours, drove it for about a minute to the get into a bay at the car wash and after a little wait to let the headers cool down had at it. First I did the "engine clean" setting and went all over the compartment and radiator area. Then I switched to soap and finally rinsed like crazy. I disconnected the injector plugs and blew them out then let them air-dry while I towelled everything down. WOW did it work! I had the intake manifold off recently and was disgusted how dirty the top of the block and thermostate housing were. While it was apart I went at it with Simple Green and a tooth brush and it did not even touch it. I gave up and put everything back together dirty. Now, after the power car wash if you look down through the intake runners you can see that the top of the block is a nice clean aluminum color (I had sprayed stright down ont he engine taking care to blow through the intake runners). I do not know what chemical thsoe car washes use for the "engine clean" function, but it works (and did not do any damage to the powder coating on the intake/valve covers).