Model-level reading
What changes the warranty calculation
85 submitted complaints appear in the BMW X4 file. They stretch across 12 model years, with the middle annual count at 7.
Report volume peaks at 18 for 2015. Without registration counts or equal vehicle age, the peak cannot serve as a defect ranking.
Among the matching repair categories, Engine replacement or major internal repair tops the parts midpoints at $7,000. That is the system I would locate in both the factory warranty and any proposed service contract.
