3 ms·

Does anyone know how putting diesel into the motor oil causes the engine to "[run] more smoothly and [use] less fuel"?

• kenz0r 11y ago
  It thins the oil, so there are less frictional losses, at least until the bearing surfaces get damaged.
  • chrismbarr 11y ago
    So why isn't oil like this normally? Are the downsides to doing this?
    • jacquesm 11y ago
      Yes, it shortens engine life.
    • maxerickson 11y ago
      There is a general trend towards specifying lower viscosity oils: http://www.consumerreports.org/cro/news/2012/09/fuel-economy-race-brings-expensive-oil-to-inexpensive-cars/index.htm http://www.consumerreports.org/cro/news/2012/09/fuel-economy...