Oil advice & recommendations from oilman @ Opie Oils

[oilman]

Lots of things. The obvious ones are the quality of the basestock oils and additives used. The main other thing is quality control. Good oil companies will do a lot of testing on each batch of oil to make sure it is what it's supposed to be. Less reputable companies may only test one in five or one in ten batches and that can lead to the oil not meeting the specifications that it's supposed to and the oil might be a totally different grade to what it's supposed to be (like an oil that says 5w-40 on the label, is actually a 20w-40 in the can).

Cheers

Tim