Used ATF contains micro sized friction materials as well varnish and metal. Magnet will help with the metal, everything else will pass thru the filters. What it does to pumps, injectors or cylinder walls, feel lucky? Oil reduces octane numbers considerably in a gasoline motor, why would it be different in a diesel? Have you ever added gasoline to start a diesel and the results were?
Years ago that guy with the 200 mpg carb would not sell out to car manufactures or oil companies, later on he vanished like no body to be found. Foul play who knows, he was originally from Arizona. He had a heating system to vaporize the fuel instead of droplets of fuel a carb delivers but then carb supplied fuel droplets vaporize due to intake heat and pressure drop. With fuel injection things are better but not the best like direct injection for gasoline motors which will be available soon. Wait until the throttle less motors come out were idle to full power is controlled by valve lift and duration only without any air duct restrictions, BMW has it and gained 11% hp and 13% Tq right off the get go. Sorry getting off topic but in the general area.
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