Once you've managed to decide the type and viscosity of motor oil you should probably be using
, the question then comes down to determining which of the oils that meet your criteria are the best of the bunch. In most respects, the only way to really make that determination is to check the specs. It's not a perfect technique, since the specs can "lie" in some ways, but, it's the best option you've got. In order to help you with those comparisons, I've implemented a free online oil comparison database that will allow you to quickly and easily compare the specifications for over 650 different motor oils.