Why do ethanol vehicles require a certain type of motor oil? Does this refer to
dedicated ethanol vehicles only?
Response:
Ford no longer requires the use of synthetic oil
in the flexible fuel (FFV) Taurus when operated on either E85 or unleaded
gasoline.
To the best of our knowledge, Chrysler does still
require a special FFV engine oil. The concern here is that uncombusted ethanol
(especially during rich cold start conditions) may migrate past the piston
ring resulting in cylinder wall washing which reduces cylinder wall lubrication
and could run down into the crankcase, diluting the engine oil.
While such occurrences are unlikely, the special
engine oil adds an additional degree of protection until more field experience
can be accumulated. These requirements apply to Chrysler FFV minivans if
they are to be operated full- or part-time on E85.
