I need help choosing an oil for a car, and I can’t quite decide what would be ideal no matter how much I read and search. First, I’ve read BITOG periodically for about eight years, but this is the first time I’ve needed to ask a question. Really like this site and the high quality responses. I’ve read Dr. Haas’ “Motor Oil University” to get up to speed. I've searched and read about a few opinions on this engine, but not this exact scenario so I have to ask. Car: 2002 Lexus ES300. 224,500 miles. Excellent cosmetic and mechanical condition throughout. Current Usage: ~1,200 miles/month, or 15k/year. Mostly 45 mile round trip daily commute at 50 to 70 MPH, interstate + smooth state highway road mostly. Little real “city” driving. Seattle area, so yearly operating conditions are from 30F to 85F mostly, with 80% of it between 48F and 70F; so pretty narrow temperature ranges. Car was driven in North Texas the first three years then the last nine in Seattle, so it has never seen a real winter. The vast majority of the high mileage has been true highway/interstate miles. Car condition is excellent, 9/10 (or better) cosmetically and mechanically. Recently I redid the timing belt again. Has all correct fluids and synthetic transmission fluid, and are changed on schedule or ahead of schedule. I have had the oil control valves out recently to inspect (they control the variable valve timing gear via oil pressure modulation for those unfamiliar with Toyota VVT engines; critical to oil health). They were both very clean. Inside of valve covers clean, too. Not "spotless" - varnish here and there but no sludge, etc. After 2,000 miles since last oil change, oil is golden with some black dirt/contaminant in suspension visible. Oil has been the recommended 5w-30 mineral oil at 3k to 5k or intervals (Toyota spec is 5k). The engine purrs flawlessly and recently I redid the suspension springs and struts; the car just runs and drives like new. The engine is the Toyota 1MZ-FE used in V6 Camrys, Toyota Highlanders, Lexus ES and RX models, Toyota Avalons from 1996 to c. 2007. We really like this car and want to keep running it several more years; maybe a long time. I want to get maximum engine wear protection in line with reasonable OCIs. I am thinking of switching to a full synthetic. I see people who are fans of Castrol Edge, Mobil 1, Pennzoil Platinum. I am unfamiliar with the last few years of advances in synthetic technology. As mentioned, I read through Dr. Haas’ “Motor Oil University” on the forum to get up to speed as best I could. I have the following questions, and open to other suggestions of course: - Is this change mineral->synthetic a good move at this age/mileage? - Should I look at an “extended performance” formulation, or “high mileage” formulation? - These engines are great, but have a reputation for sludging if oil is neglected. What OCI should I do with a (given) synethetic with our usage profile, wear protection goal? - What would a good synthetic be if I going that way is good? - Should I consider another weight, 0w-30, or 0w-20? Toyota has backwardly spec’d 0w-20 and 5w-20 for the engine in addition to original 5w-30 specification. Based on Dr. Haas’ information, this sounds like a good idea to me. Or should I be more conservative given mileage? it does not burn oil with mineral 5w-30 and mileage on engine. - If a longer OCI, should I change filter more often, or just always do new filter and oil at the same time? Opinions are deeply appreciated.