is it a big deal choosing the good ranked Oil?
Go as far down the list as possible, eg. ST.
S means spark ignition, the alternative being C for compression ignition, or Diesel motors. The letter following the S is the standard or standards met. The higher the letter the better. If you are looking to use one of the synthetics that doesn't carry an API rating, there are two reasons why they would do this. First, it costs a lot of money to have an oil certified. The fact that they aren't willing or able to spend that money is probably something to think about. But the other reason is that current API specs require low levels of the anti-wear additive ZDDP. It's being removed, because even in small quantities, it can poison catalytic converters. The new additive packages are more expensive, and so we come back to the question of why you would buy oil from a company that can't afford certification.
