Communicate the discovery and cause of excessive fuel
dilution in 2007–2010 light-duty diesel pickups from Ford,
GM and Dodge and the resultant reduction in the drain
interval recommendation for AMSOIL Premium Diesel Oils
in these applications.
AMSOIL has documented increasing levels of diesel fuel
contamination (fuel dilution) in the engine oil in 2007–
2008 light-duty diesel pickups from all major vehicle
manufacturers, and indications are that 2009 - 2010
models are affected as well.
Research indicates that fuel dilution is intensifying due to
the use of in-cylinder post-fuel injection during the engine’s
exhaust stroke to regenerate the diesel particulate fi lter
Fuel in the oil reduces the oil’s life expectancy and
effectiveness. Because diesel fuel is a natural solvent, fuel
dilution in motor oil causes a decrease in viscosity which
may lead to an increase in engine wear rates.

Read more here: AMSOIL Technical Service Bulletin