A couple of years ago GM
A couple of years ago GM voluntarily asked owners of 2010-2012 of the GMC Terrain, Chevrolet Equinox, Buick LaCrosse and Regal with the 2.4 liter four cylinder engine bring their vehicle back to the dealer for the reprogramming of the oil monitoring system. Seems the elevated warranty claims on this engine was diagnosed as oil change intervals that were too long. The reprogramming shortens that interval. Almost 800,000 vehicles were involved. I change my oil and filter every 5,000 miles. I use synthetic oil. On my '09 Corolla I can look through the oil fill hole in the top of my valve cover. After 135,000 miles with 5,000 mile intervals, the valvetrain looks just as clean today as when I bought it. I would not have believed it if I had not seen it with my own eyes!