Navistar expresses "disappointment" in investor Carl Icahn, saying it has strategy to turn the company around.
EGR-only engines put up to six pounds of soot into oil during a 40,000-mile interval.
Navistar will move from EGR and adopt the SCR path taken by its competitors to meet 2010 diesel emissions regulations.
A court rejected the ruling that allowed Navistar to sell heavy-duty diesel engines that don’t comply with emissions standards.
Company sought to force the U.S. Environmental Protection Agency to recall 2010 model year engines using selective catalytic reduction.
Most manufacturers have yet to extend change intervals, but oil seems to thrive in the new engines.
Navistar alleges nitrogen oxide emissions skyrocket when drivers don't keep diesel exhaust fluid topped off.
Agency calls on SCR engine makers to develop warning systems that alert drivers when diesel exhaust fluid tank is nearly empty.
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