Muddy waters and the bearing blues
Some 2009-2013 Mazda6 vehicles equipped with the 2.5L engine (produced before Feb. 15, 2012) and the 3.7L engine (produced before July 18, 2012) may exhibit an unusual humming noise from the front wheel bearings.
This may be caused by muddy water (or other contaminants) entering the wheel bearings, which causes the bearings to rust.
The bearing seal has been improved to eliminate this concern.
When installing the improved bearing, be sure to replace the retaining clip, dust cover and locknut with new parts.