Wife's car 2003 toyota avalon has 17'000 miles with 5w30 conventional,Interested in running GC 0w30 at next OCI (20'000) can GC 0w30 be used year round? 0-40 in winter with some days hitting -20 and staying 0 all day, summer is 75-95. Toyota recomends 5w30 year round, we plan on keeping this car for a long time and have been reading about (GC) on this site and it seems to be a great moter oil. The AZ where I live does have it, Being my wifes taxi only the best will do Thanks for your imput
