What is base oil?

Base oil is produced from refining crude oil. This refining process requires heating separating light and heavy hydrocarbons. Light ones are used for producing petrol and other fuels. Heavy ones are more suitable for bitumen and base ois.

What are the different types of base oils?

American Petroleum Institute (API) cateorized base oils into five types based on viscosity and the proportion of saturates and sulfur content among all the other properties. Currently, these five base oils are used in engine oils of all different specifications.

1. Group 1. API defines it as  "base stocks contain less than 90 percent saturates and/or greater than 0.03 percent sulfur and have a viscosity index greater than or equal to 80 and less than 120". It is used in what we normally call conventional oil.
2. Group 2. It is a better grade of Group1. API defines it as "base stocks contain greater than or equal to 90 percent saturates and less than or equal to 0.03 percent sulfur and have a viscosity index greater than or equal to 80 and less than 120".
3. Group 3. It is the best grade of petroleum base oil. API defines it  as "base stocks contain greater than or equal to 90 percent saturates and less than or equal to 0.03 percent sulfur and have a viscosity index greater than or equal to 120". Although Group 3  engine oils are based on petroleum base oil some engine oil manufacturers call Group 3 engine oil as synthetic oils.
4. Group 4. Consisted of synthetic oils made of Poly-alpha-olefins (PAO) , Group 4 based engine oils have higher oxidative stability, low pour points. and a viscosity index range of 125 - 200. PAO oils are more suiable for very cold or very hot climates.
5. Group 5.It is anything that is not defined from any of the Group 1~ Group 4.

What are the main properties of base oil?

1. Pour point.  It is the lowest temperature at which oil can be poured.
2. Viscosity.It is the resistance to oil's flow. How fast and slow oil can flow determines the viscosity.
3. Viscosity index (VI). Viscosity index is defined  by the Society of Automotive Engineers (SAE). This is what we normally use in choosing the engine oil. Different temperatures will affect oil's viscosity and such results are categorized with Viscosity Index (VI).
4. Purity. Defines limits of different lubricants including sulfur, nitrogen and polycyclic aromatic compounds.

Major functions of engine oil

1. Lubrication: Engine oil plays important roles in protecton of engine parts by forming a very thin layer of oil film offering best possible lubrication between moving metal parts.
2. Decontaminants: Engine oil contains properties that could remove any harmful byproducts from the engine. In the process of oil flow from the oil pan to the strainer, the oil filter, and then to the engine, engine oil collects such contaminants which are then filtered by the oil filter.
3. Engine Temperature Control:  Engine oil is used for heat dissipation from the engine. It is known that approximately 40% of the engine heat is removed by engine.
4. Engine Performance: Engine oil seals microscopic spaces between the piston and cylinder for optimum perforance. Without such seals, proper pressure may not be realized potentially causing issues including miss fire.

What are the types of engine oil ?

1. Fully Synthetic Oil. It is engineered to offer higher viscosity, better resistance to corrosion, oxidation. Typically fully synthetic oil is recommended for high performance engines.
2. Semi-Synthetic/Synthetic Blend Oil. It is like a hybrid of conventional and fully synthetic oil. It is the optimum choice between the conventional and expensive fully synthetic oils. It offers better resistance to oxidation with low-temperature properties.
3. High Mileage Oil.For long distance drivers, this high mileage oil is recommended with unique formula optimized for oil seals, oil leaks, oil burn-off, engine smoke and emissions as well.
4. Conventional Oil. It is the engine oil manufactured from crude oil and refined with different viscosities.

How do I chooose the right engine oil?

Each vehicle is different, it is always recommended to refer to your vehicle's manual. Normally, recent engines require 0W-16, 0W-20, 5W-20, 5W-30. Wrong specifications of engine used could potentially  cause issues with your engine system.  For example, If engine oil is too thick in cold start up, engine oil could not flow as designed thus not being able to proect the engine effectively.

How often should I replace engine oil?

Again, you need to refer to your vehicle's manual. Typically, car manufacturers recommend about 10,000km intervals. However, some change engine oil in every 5,000km. It all depends on oil specificiations required by your engine and your driving environments.

Should I change oil filter every time I change engine oil?

For example Honda recommends replacement of engine oil filter in every 20,000km. Some change oil filter in every 10,000km. It all depends on your choice.