Selecting a good engine oil for your car?

Oil selection?!! Headache!

Selecting and using the right engine oil for your car is as important as eating healthy food. Using a good quality oil will not only make your car drive and feel good but it also keeps the engine healthy for a million miles and more.

The Recommended Method

This one is really simple and when in doubt follow the owner's manual. Your car's owners manual has the necessary information to help you select the correct oil for your car, it will tell you what viscosity and what grade of motor oil to choose. Just follow that and that works for most if not all.

The "Tender Loving Caring" Method

If you do not want to go by what your manufacturer words and is in a mood to do some reading and researching you might want to go this way. You are an enthusiast after all isn't it? Let me warn you that if you are not keeping track its easy to get derailed and confused, but there is a tool with which you can pull some sense out of this!

The Tool

Relative Performance Tool

Lubrizol Relative Oil Specification Comparison Spider Chart that literally compares relative performance among the different oil specifications. But be sure to read the disclaimer though "The performance charts are not a literal translation of a performance specification and should not be used as a replacement for evaluating engine oil performance in accordance with the relevant vehicle manufacturer’s requirements". But still this chart gives a overall fair idea regarding performance of various engine oil standards, which is very useful!

For example:
Mobil1 0W40 meets or exceeds the latest API SN (supersedes API SM) certification but it also has MB229.5 approval from Daimler among other OEM approvals. Now if you look up the oil specification of API SN standard in Lubrizol chart you can see that API SN standard is mostly about reducing oxidation thickening and piston deposits rather than offering good wear protection which we as an enthusiast expect from an oil!

Now observe the MB229.5 specification, this standard offers a lot more in terms of wear protection and other areas than the API SN standard. This means that MB229.5 is a standard that is vastly superior to API SN or SM and oils meeting this standard will offer more in terms of wear control, sludge prevention, reduced oxidation thickening, piston deposits and fuel economy when compared to an oil meeting only API standards.

API SN




API SN vs MB229.5



The owners manual of your Swift recommends that you use engine oil meeting the quality classification of API SG, SH, SJ, SL or SM (All of these has been superseded by API SN but old grades are available in the market). When you are getting the oil changed if you decide to use a good oil that complies with the most recent API quality requirement, like SN or SM, the engine will do fine as it offers basic protection as mandated by that quality standard. What you should be aware of is that oils with the obsolete API approvals are still made and sold in the market, and the manufacturer says its OK to use some of them (SG, SH, SJ) so if you use these obsolete standard oils you should be aware that these may not even provide as little protection as SM or SN oil will because the older standard calls for lower requisites, see the image below. But if you decide to use an oil that qualifies the API standards alongwith the more stringent OEM approvals your engine should do a lot better offering excellent and consistent performance.


Total Base Number (TBN)

If you have access to the technical data sheet of the oil you want to buy, note down the Total Base Number (TBN) of the oil if provided in the spec sheet. The TBN value is the numerical representation of oil's ability to resist the acids formed in the engine as a byproduct of combustion process. Higher the TBN stronger the Base (or Alkaline) value of the oil which helps resist the acids making the oil remain effective for longer prolonging the drain interval.

PS: I would still recommend sticking with manufacturer's oil change interval if you do not have access to Used Oil Analysis service to make an informed decision otherwise.