Frequently Asked Questions
What do engine oils do?
An engine is made up of a large number of important moving parts, such as pistons, crankshaft, valves and the camshaft, etc., and engine oil plays several important roles in ensuring that these all work together properly.
1) As a lubricant. Reduces friction and wear that occurs when parts move against each other, for example between the cylinder liner and piston ring, or the camshaft.
2) As a coolant. Absorbs the heat produced in the engine combustion chambers and piston undercrown area, cooling the engine and helping to prevent overheating.
3) As a sealant. Seals the space between the piston ring and the cylinder liner to prevent combustion pressure (engine power) from escaping.
4) As a detergent. Prevents waste matter resulting from combustion and impurities produced by oxidation from sticking to the engine interior, helping to keep it clean.
5) As a rust inhibitor. Neutralises acids produced by combustion gases, preventing rusting and corrosion.
2) As a coolant. Absorbs the heat produced in the engine combustion chambers and piston undercrown area, cooling the engine and helping to prevent overheating.
3) As a sealant. Seals the space between the piston ring and the cylinder liner to prevent combustion pressure (engine power) from escaping.
4) As a detergent. Prevents waste matter resulting from combustion and impurities produced by oxidation from sticking to the engine interior, helping to keep it clean.
5) As a rust inhibitor. Neutralises acids produced by combustion gases, preventing rusting and corrosion.
Why do you have to change oil, and what happens if you don't?
Engines work through the process of burning fuels such as gasoline. As a result, non-combustible by-products such as residual gases and soot are produced. Engine oil captures and prevents these impurities from coagulating inside the engine and works to keep it clean but as it does this its effectiveness diminishes. The effects of combustion heat and oxygen in the air can also cause engine oil itself to deteriorate, and therefore it is essential that the oil be replaced after a period of use.
Continuing to use engine oil past the manufacturer's recommended drain interval can cause a build-up of sludge, which could inhibit piston ring movement and in the worst case can cause the oil to become sticky and tar-like, leading to engine trouble. Replacing the oil flushes out the dirt, impurities, water and other particles that adversely affect the engine. To protect your engine and keep it running smoothly, it advisable to change your oil on a regular basis.
What sorts of intervals are recommended for changing engine oil?
The standard criteria for changing engine oil are distance and time. Generally, 3-5,000km or 6 months (whichever is first) is the interval normally used in Japan. Although the actual trend for oil change intervals as specified by the manufacturers is trending towards 10-15,000km plus (or once a year), to really keep an engine consistently working in prime condition people often replace their oil at shorter intervals. Furthermore, for vehicles that have higher power output, turbo cars and diesel cars, or those on severe drive cycles, short change cycles are recommended depending upon conditions of use.
It may seem strange, but using your car for short trips only (such as a quick 10 minute or so visit to the local supermarket) means that the engine oil does not heat sufficiently and water and fuel can accumulate in the engine, leading to a build-up of sludge and rust, and causing wear. So, in actual fact, the belief that the car has not covered much distance and therefore changing the oil isn't necessary is misled. The true condition of the engine oil in a car is difficult to assess and careful regular maintenance is important to maintain peak performance.
Can you use gasoline engine oil in a diesel car and vice-versa?
Because gasoline engines and diesel engines run on different fuel, they have different characteristics and therefore the performance requirements of engine oils must also vary accordingly.
Dispersion cleaning properties (washing out residual particles such as sludge to keep the engine interior clean) and anti-wear protection for the camshaft are especially important in gasoline engine oil. Furthermore, gasoline engines are equipped with catalysers to purify exhaust fumes and an oil formulation that prevents adverse effects to these is essential. Diesel engines, on the other hand, produce more soot and so an ability to control the soot build-up is crucial. Also important are antacid properties to neutralise the acidic particles that are produced by the combustion of sulphur present in diesel fuel. As particular emissions are more controlled vehicle manufacturers are designing engines with emissions equipment that requires high performance oil.
Consequently, it is not advisable to use gasoline engine oil in a diesel engine, or diesel engine oil in a gasoline engine. The SL, SJ, etc. performance ratings of gasoline engine oil all begin with the letter 'S' (Spark ignition), and the CF, CD, and so on of diesel engine oils with 'C' (Compression ignition), so it is quite easy to tell them apart. [Gasoline/Diesel dual use] engine oils that carry the rating [SJ/CF] have been specifically formulated for both types of engines and can be used in either, according to conditions of use.
What is the difference between synthetic oil and mineral oil?
Mineral oil is derived from crude oil. Once gasoline, kerosene, diesel, heavy oil, etc. have been distilled from crude oil, the heavy remaining constituent is refined to produce mineral oil, which forms the main ingredient (often termed the base oil) in some engine oils, gear oil, and so on. Engine oils that are produced using this mineral oil and enhanced with chemical additives, are known as 'mineral based oils'. Since mineral oils are derived from natural products they all have a level of impurities present which reduces performance slightly.
Synthetic oil, on the other hand, is chemically produced from a resource such as naphtha. Compared to mineral oil, it contains almost no impurities and has far superior characteristics, including viscosity and resistance to extreme heat. Because of its extremely high performance and quality synthetic oil, which is chemically engineered, is targeted more toward applications where maximum performance is required.
A combination of these oils, which mixes mineral and synthetic oils together, can be known as 'part synthetic oil'.
Does using off-the-shelf oil enhancement products cause any problems?
The chemical additives contained in engine oil have been carefully and specifically formulated to suit that particular oil's performance requirements. Adding more of these additives upsets the chemical balance and can adversely affect the original performance qualities. There is also the possibility of exceeding limits affecting fuel consumption and gas emission restrictions for which the original oil received approval.
The biggest issue, however, is that the resultant mixture will not have any of the oil tested performance approvals such as API, ACEA, OEM, as the additives level will fall outside the tested levels.
Swallow engine oil?
In the event that someone accidentally swallows engine oil, give plenty of water or other mild drinkable fluids and call a physician immediately. Do not induce vomiting.
Should oil get into the eyes, flush with clear water for at least 15 minutes or until irritation subsides. If irritation persists, seek medical attention.
In case of contact with the skin, remove contaminated clothing and wash before reuse. Wipe excess material from skin. Wash exposed area thoroughly with soap and water.
**Please be advised that the above refers to engine oil and that first aid measures may vary according to oil products. In accordance with the Product Liability Law, every oil product displays a [warning] message, a [caution when handling] message, [first-aid measures], [oil and container disposal guidance] and [storage instructions]. Please be sure to read these carefully.
Does adding too much or too little oil cause problems?
Adding too much oil can cause increased oil consumption as the lubricant is drawn in through valve guides, etc., so please ensure that you adjust to the correct level.
Too little oil can affect the oil pump's ability to draw up oil so make sure that you regularly top up with the same oil to maintain the correct level.
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