GM had some warranty issues with cams and bearings years back. Most all the failures had a intake manifold resealed 3- 6 months prior. The 3M Scotch Brite pads were used for cleaning the intake surfaces, and there was material in the oil filters and oil pan. They were also charging the dealers back for warranty repairs if Scotch Brite pads were used. https://gm.oemdtc.com/TSB/MC-10082814-5448.pdf
