My professional recommendation would be to run ONLY Mobil 1, Amsoil or Redline, PAO/Ester based synthetics in the Camry V-6 engine. This will allow you to run 7500 mile oil change intervals and still get excellent long term results. I have discussed this issue with all of the Amsoil dealers here in Huntsville, Alabama and we all agreed that anything over 7500 miles is pushing it in this motor. One of my coworkers has a 1999 Avalon with 150,000 miles on it; running oil change intervals of 7500-10,000 miles under highway driving conditions. The engine is still in excellent shape and consumes no oil between changes running a 0w-30 synthetic. So I know this protocol will work fine ....
Based on what I've seen in terms of oil analysis results from this motor, if I was crazy enough to run a petroleum oil I'd be changing it every 2500 miles ....I'd use a 10w-30, Group II basestock with perhaps 100-150 ppm of moly in it ....
TooSlick