Jim, in the GM 2.4L I often see 3-4% fuel dilution and up to 9-10% during cold weather driving. Using 5W-30 oil. I tried different types of oil and saw an improvement in oil stability. The SuperTech FS lasted less than 2k before it shared to 20 weight. I tried AC Delco FS from the dealer, which is made by Mobil/Exxon, and it lasted 2500 miles. I then tried Amsoil Signature Series for 4500 miles before it sheared to a 20 weight. I finally went to the Amsoil 0W-40 European and now at 11k miles and it is still a 30 weight oil, and wear rate is 4x lower. GDI is hell on oil and that does not consider the abrasive soot that contaminates the oil. I use a 2 micron bypass to keep clean. These engines as you may know have suffered, excessive wear, timing chain wear, and oil consumption (rings sticking). I have been asking for years for data on viscosity shearing due to fuel dilution from oil manufacturers. Some even claim up to 7% is acceptable, including Polaris Labs. I've given up and just resort to the next higher grade of oil, and a high quality Group IV. Recommend TestOil for oil analysis on GDI engines. Includes TBN, oxidation, and Particle Count and the GC fuel test is highly accurate and they go up to 10%. I wish Blackstone would start using GC.