New to this site but am amazed at the amount and variety of information. My 1998 Sienna has 74,000 uneventful miles on the infamous V6 prone to "sludge" occurence. At this point, I have been changing the oil every 4,000 - 5,000 miles (never felt comfortable with 7,500 mile interval) using Valvoline All Climate 5W-30 with Toyota's OEM filter. I hope to get 200,000+ miles from our van. Looks like the interval should be dropped to 3,000 to be safe. I am interested in any additional changes or items BITOG members would recommend to help me have the greatest chance of avoiding a Toyota warranty discussion due to "sludge" and make it to 200,000+ miles (e.g. treatment with Auto Rx, changing oil brands, etc.). Hopefully this horse has not been beaten to death in earlier posts. Thanks!