Re: Things you must know while selecting engine oil

In your write-up, your enumerated four points as the things you must know while selecting engine oil starting with the type of oil one has been using followed by the age of the vehicle then manufacturers specification and finally, the weather condition.All the points you raised, are among some of the things oil manufacturers consider […]

In your write-up, your enumerated four points as the things you must know while selecting engine oil starting with the type of oil one has been using followed by the age of the vehicle then manufacturers specification and finally, the weather condition.
All the points you raised, are among some of the things oil manufacturers consider when formulating the engine oil. They don’t label the oil containers with these points you raised but they follow the International System (SI) set by the society of automotive engineers (SAE) and the American Petroleum Institute (API). There are basically two things you must know while selecting engine oil for your vehicle, after knowing the vehicle manufacturers specification.
These are:-
i.    SAE  grading
ii.    API classification.
These two informations are always labeled on the oil containers (Gallons)
•    SAE grading: The first information you look for speaks to viscosity grade. The society of automotive engineers (SAE) defines a numerical system for grading motor oils according to viscosity. It is always boldly written as SAE 30, SAE 40 or SAE 50 on the container. The higher the number the thicker the oil.
As the automotive technology improves so also the formulation of engine oils. The improvement in technology brings us to multi-grade oil where you have labels like SAE 5W-20, SAE 5W-30, SAE 0W-20, etc. Note “W” designates the engine oil winter grade. 
•    API classification: The next “Code” to look for is the API (American Petroleum Institute) classification. The API classification, classified engine oils into gasoline (Petrol) engine oil and diesel (Gas) engine oil. Oils design for gasoline engines fall under API’s “S” (Service) categories, while that of diesel engine fall under API’s “C” (Commercial) categories.
The API classification uses alphabets from A – N in an increasing order of quality, omitting letters I & K. If an engine oil is labeled API SC or SF you should know that the oil is for gasoline engine. If it reads API CC or API CF you also should know that the oil is specifically formulated for diesel engines only and cannot be interchanged with the “S” class.
There are also the universal engine oils that can be used on both the gasoline and diesel engines. They are normally labeled as API CF/SL.
Other things to know while selecting engine oil includes the API certification mark, also known as “Starburst”. An oil displaying this mark meets the current engine protection standard and fuel economy requirements of the international lubricant standardization and approval committee (ILSAC), a joint effort of USA Japanese automobile manufacturers.
ILSAC standard for passenger engine oil are specially formulated to provide improved high temperature deposit protection for pistons and turbo chargers, more stringent sludge control, improved fuel economy, enhanced emission control system, etc. the ILSAC standard for passenger car oils are designated as GF-1 to GF-5 being the latest.
And for diesel engine we have labels like CH-4, CI-4 and CJ-4.
When next you walk into a shop to buy engine oil do not  allow price to guide you on which oil to buy. You should always be guided by the SAE and API labels. For example, if you are using Honda ‘98 Accord (baby boy) or Toyota Corolla 2005 model then you are looking for SAE 5W-30, as specified by the manufacturers.
Multi-grade oils such as SAE 5W-30 and SAE 10W-30 are widely used because under all but extremely hot or cold condition, are thin enough to flow at low temperatures and thick enough to perform satisfactorily at high temperatures.
Now that we know the things to know while selecting engine oils, the next issue is to know how authentic are the SAE and the API standards on our oils? Are the oil contents really what they are label to be? These are issues that can only be answered by the standards organization of Nigeria (SON) and the NNPC.
I sincerely commend your effort for raising this sensitive and very important issue.
Njidda is Organizing Secretary, Nigerian Automobile Technicians Association (NATA), FCT Chapter. [email protected]