Originally Posted By: Valentine
Hey,thanks to everyone for their advice. Just to clarify, I wasn't trying to select an oil for a particular vehicle. I was wondering more about how you pick one oil over all the other choices which appear to be so similar. For example, my Wife's vehicle is a 2015 Hyundai Sonata. I believe the manual for that vehicle calls for a 5w-20 conventional oil but I'm currently running Mobil-1 0w-20 in it. I got a good deal on the Mobil-1 and that was the primary reason I chose that oil over the other brands which were available to me. That and that fact that Mobil-1 is so highly regarded here. I guess my real question is how does an average guy like me know that Mobil-1 is actually better than Supertech Synthetic or any of the other brands sitting on the same shelf? I know Royal Purple is a cool color but besides being more expensive, is it actually better than other brands? If so, what is it that makes it better? I've always been a "most bang for my buck" kind of guy. I Don't want to get too far from the original point of my post which was simply trying to determine what qualities to look for when selecting one oil over all of the choices which are available.
-Valentine
Well, when you get down to it, any oil that matches what your car's maker recommends/requires is probably fine.
But, here's a summary of my oil selection process for your amusement.
When I started changing my own oil, I wanted to use synthetic 5W30 as Subaru recommends to avoid any warranty complications. Mobil 1 is the synthetic that you always hear about, so I bought some of that on Amazon...only to find out that it is cheaper at WalMart for me. Anyway, I noticed other oils like Royal Purple, Texas Tea, and Redline on Amazon and got interested in them.
Started poking around online and found that some people felt the specialty oils were "better" because they are made from superior synthetic stocks than M1, which was alleged to be derived from chemically modified crude (which I think is largely true). I found some evidence that Royal Purple used "better" (group IV) base oil, so I bought some of that at WalMart at about $10 more than M1 for my next change.
Then, I saw some crude cold pour tests on YouTube that made RP look really bad at low temps. I ski and often park my car outside overnight in very cold conditions for winter weekends, so this freaked me out. Then, I found this website...
http://www.pqiamerica.com/March2013PCMO/Marchsyntheticsallfinal.html
I studied up on what the various test results meant and decided Quaker State Ultimate Durability looked really good, and it is cheaper than M1 at WM. This site also verified that the RP cold viscosity was higher than most of its competitors. I was able to return the RP and bought some QSUD, which I used for my next change.
Then, I started seeing discussions online about Direct Injection Turbo (DIT) engines like I have and problems with knock-like events. Found this paper which investigated a possible link between these events and calcium in motor oil...
http://papers.sae.org/2014-32-0092/
QSUD had significantly more calcium in its formula than M1 according to the PQIA, so I have switched back to M1 for now. Castrol Edge had even lower calcium than M1, but its cold viscosity was about the same as the RP that scared me a few months before. It is worth noting that both of the Pennzoil products in the PQIA chart have been reformulated since 2013, I believe they have test results for the newer products if your search around on that rather Byzantine website (which I still use a lot).
You know what, though?
I'm sure any of these oils would be fine for me. I just have fun trying to pick the "best" oil. There are some 5W30 M1 diesel oils that are interesting to me now, but they are hard to find and it is also hard to find information about them. It is interesting to me that a lot of turbo Subaru drivers (WRXs in particular) use 5W40 diesel oils in their cars, but they are not an option for me until I'm out of warranty.