There's alot of talk of oil sludge problems in the 3.0 v6 and 2.2 i4 Toyotas. I own a 99 Avalon and received a letter last year about the new policy. I had been using Mobil 1 10w-30 and changing on the recommended 7.5K normal interval since after the first 1500 mile break-in on factory oil. After the letter and research I became quite concerned. I have currently switched to Amsoil Series 2000 0w-30 and plan to change every 5k. I plan to do an oil analysis next oil change. I also noticed the PCV was rather small and plastic and seemed somewhat prone to clogging, though mine was still functioning. I replaced it also , and plan to do so on a schedule of every 10k. Right now it runs great and the oil stays very clean. Bottom line is I need this car to make it to 10 years and 150K at least. My dad has an 82 Cressida that still runs great and I had expected similar performance from the Avalon. Will what I'm doing 100% guarantee I never get oil sludge, or do I need to do more like start doing analysis periodically or pulling a valve cover every year?