Ok, so I just picked up 5 quarts of Penzoil Platinum. The lady at the store recommended me getting
10w-30 over 5w-30 because my engine has about 120k miles on it, is it better to get 10w-30 if my car has high mileage? Also, are Penzoil Platinum any good? Suggestions and Experience with using Penzoil would be nice. Thanks.