Buying Oil Shouldn’t Be This Hard

The next time you go to the store for car motor oils, take a step back, and stop pulling out your hair. There are literally hundreds of different motor oils available for purchase, and it can sometimes be confusing deciding which one is right for your vehicle. In general terms, if you simply choose an oil that meets the viscosity and API requirements listed in your owner's manual, you will likely have no major problems with your engine.

But, for those who would like to carry the discussion a little further and are not just looking for adequate (for instance, if they are looking for better performance from their engine or are specifically intending to get the most life possible from their engine), knowing a little more about oils and how their quality specifications can be compared can go a long way toward helping you find the RIGHT oil for your application.

Obviously, viscosity is one of the first issues to consider, and, although it isn't quite as critical as many people think, tweaking your viscosity a bit CAN yield big returns if you're a high mileage driver or if you work your vehicle really hard.  Knowing how and when to tweak manufacturer recommendations is important here, because moving outside of OEM recommendations (although NOT grounds to void your warranty) could cause problems in certain situations.

Viscosity is actually a VERY complicated question once you consider venturing outside of OEM recommendations, so, if you are considering that possibility, "The Motor Oil Bible" would be a good place to start learning more about viscosity, so that you can make an educated decision regarding this issue.

Obviously, make sure that the oil you are using meets the API requirement listed in your owners manual.  If the vehicle calls for an API SL rated motor oil, make sure that the oil you're planning on using is rated API SL, SM or later (API specs are backward compatible and the higher the 'second letter', the better the oil generally is - in other words sM is better than sL).

If you're driving a diesel you'll see API specs like CG, CH, CI, CJ.  The C refers to a DIESEL and the second letter establishes how new the spec is.  Again, the higher the second letter, generally, the better the quality of the oil.  Here too, specs are backward compatible, so a CJ oil can be used for an application calling for a CI oil, although this may not ALWAYS be the best option.

Beyond that, you'll want to decide whether you want synthetic or petroleum or a blend.  Typically, I'd recommend steering clear of blends.  Not worth the money.  SOME synthetics will be worth it, but, be cautious about switching an older vehicle to synthetic.  In certain situations, even though a synthetic oil will generally be of higher overall quality, a petroleum car oil might STILL be a better option for you.

The truth is, although choosing car motor oils SHOULDN'T be that hard, in some case it can be, especially if you don't at least know the basics.  That is precisely why "The Motor Oil Bible" was written.  To help people understand the basics so that they can make an informed decision instead of simply relying on clever marketing and slick sales copy.

The Motor Oil Guy