I started using Lucas oil additive in my 2008 GMC 2500HD 6.0. I had heard many issues with sludge in the oil pan and bad oil pressure when cold. I had bought the truck with 160,000 on it which was clearly hard miles. The oil pressure was not the greatest so we flushed the engine using motor flush and then if you can believe it diesel fuel. After I have run regular 10w 40 oil with a 60/40 mix of Lucas Oil Stabilizer and the truck has great oil pressure, runs like new, and has approximately 420,000 miles on it. I haven't done a thing to the motor besides flushing it and using Lucas. Since then I use Lucas in all 15 trucks we have and all 30 pieces of heavy equipment. I think Lucas makes an great product and it is the first I can remember that called my attention to additives through their old display where you crank the wheels and see the difference. -Joseph K., Plymouth, MA