What prompts your desire to clean the engine internally? Do you have evidence of sludge formation? Piston oil control rings sticking? Prior owner only changed the oil every other year?

Pull the cam cover and inspect. If there is evidence of sludge formation, then use a professional cleaner designed specifically for this problem, such as Lubro Moly's Oil Sludge Remover and/or Motor Clean, both of which are used with the engine's 8 qts. of oil in place. Diesel fuel is NOT the appropriate tool for the task at hand.