Sorry for the bad links
I hope this will help all the forum members on synthetic oil life. But i would add my two cents Change synthetic oil every 8000 miles or six months which ever is earlier with a good oil filter. I do not recommend using one year or >10000 mile synthetic oils especialy for toyota engines. For the fact any toyota engine from 1988-1998 will burn some amount of oil. Every one claims they have the best synthetic oil, yes yes yes in the labs.
I drive a 1992 camry V6 with 5W-40 synthetic oil and 180000 miles, and no problems yet?
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Stick to your 5W30 since you line in minesota, similar to our weather in canada. It is no worry if your toyota is consuming 1/4 qt for every 1500 miles.
But if you are lossing oil by a leak, fix it, changing to 10W30 or 40 will not fix the problem.
Warning: If you use 10W40 ? and the temp drops to 45 deg F, your car RPM will almost increase by 30% and may be dangerous for your engine. and as such for your state you may have temp above 50 deg F for 3 months anyway? so stick to 5W30.