go to the car wash.. put a wal mart bag over your 6637.. clean away.. i keep my engine running.. I have never had an elec issue in 315k..

 

I use a can of gunk engine cleaner, not the foamy stuff, I spray everything down, then I drive to the car wash and rinse it off, yes it will kind of stink for a day or two but it cleans good. I have been doing this for years on all of my vehicles (cars, boats, ford trucks, Peterbilts, etc) for years with no issues yet