I put Lucas Heavy Duty Oil Stabilizer in my 1998 GMC Yukon 4x4 350. First I want to say I have always maintained my Yukon like clock work. From the first oil change I used Mobil 1 and changed it every 3500 miles. At 116,000 miles I noticed after my annual hunting trip my dip stick was a quart low with 600 miles since my last oil change. Since day one my truck never went below the top reading on my dip stick. I emailed Lucas and got a quick response stating that it maybe blow by and suggested staying with Mobil 1 and substituting one quart with Lucas Heavy Duty Oil Stabilizer making my oil a blend. Thank you I took your advise and my oil pressure went up and oil consumption went away. I noticed at highway speeds my oil pressure went up 7 pounds and the engine runs cooler. My 350 woke up and has more power and the thought of a new Chevy Tahoe purchase went away. Thank you for that email I am sold and will continue to use your products!