GM Defeats Excessive Oil Consumption Engine Defect Class Action

General Motors LLC won summary judgment in a proposed class action over an alleged engine defect after a federal judge ruled that the named plaintiff couldn’t prevail without expert testimony that had been excluded.

Without expert testimony on the root cause of the alleged defect, a jury wouldn’t be able to determine whether that defect caused excessive oil consumption as the customer claimed, the US District Court for the District of Colorado said Tuesday.

Earlier this year, the court found the expert’s opinions that piston ring wear caused the defect were unreliable because he failed to explain what engineering principles ...