I'm one of the odd ones out.. I use artists oils for most of my washes, I use Turpenoid (synthetic, odorless turpentine) to thin it. Because it is mostly thinner when it is put on you have about 12 to 24 hours to play with it then another 12 to 24 till dried. These work well around engine areas and for panel line washes... it also works well because wround engines you can simulate oil leaks from access panels...
other than that I use acrylics on wide open areas where I don't worry about some accumulating in a crevice and drying before I have time to get it out...