Frequently Asked Questions (FAQ)
What’s the difference between synthetic and mineral oil?
Synthetic lubricants are made up of molecules that have been modified under complex chemical processes and allow for enhanced performance under extreme conditions of temperature, pressure and forces. Mineral lubricants are composed of molecules present in crude oil that are separated in the distillation process at a refinery.
What is viscosity?
A liquid that has a relatively high resistance to flow can be described as viscous. For example, water has a low viscosity compared with honey, so in this case honey has a higher viscosity than water under the same temperature. A good quality lubricant keeps its viscosity steady under different temperature and usage conditions for a longer period of time.
What is multi-grade oil?
Lubricants that are able to maintain their performance in high and low temperatures are called multi-grade. They are defined by two numbers. The first (followed by a W) indicates the lubricant’s viscosity under lower temperatures. The second and higher number indicates the lubricant’s viscosity under greater temperatures. A multi-grade lubricant minimizes viscosity differences under temperature variations.
What are additives and why are they used?
Additives are chemical compounds which, when added to base oils, improve the performance of the lubricants, protecting them from aging and allowing them to respond to all the demands of the modern engine. The blend of various additives is what sets a quality lubricant.
My oil consumption is very high. Why?
You would be wise to check for faults, taking into account the type of engine, its age and the driving conditions to which it has been exposed. Faults could be caused by a leak in junctions or seals, wear to pistons or cylinders, or deposits limiting the lubrication of some surfaces.
Does the color of the oil mean anything?
The color of an oil has no special meaning, but depends on a number of factors, such as the refining process and the types of base oils, additives and crude oil used. Oil may turn a darker color after use because it contains a number of suspension particles – the reason for this is that oil cleans the engine of particles and other deposits produced by the high temperature combustion, keeping the particles in suspension to avoid depositing them on the engine’s surface.
What do the classifications and specifications on the back of the pack mean?
Lubricants vary in their use and quality. Some are only suitable for particular engines, while others can only be used in certain climates. Even two oils optimized for the same engine and climate conditions can have vastly different levels of performance. Universal criteria to describe oil performance and usage are therefore used. In your car manual there are details on the motor oil specifications required for your engine. When choosing motor oil it is important that the product you select meets the specifications in your car manual.
Why does my oil go black almost immediately after an oil change?
The oil should go black as it disperses and suspends the soot. If not held in a finely dispersed form by the oil, the particles would stick together forming sludge that could block oil ways or large hard particles that could wear bearings, cam lobes, etc. Essentially the oil is doing its job. If an oil takes time to go black it is not performing as well as the oil that goes black quickly.
If I change from another engine oil brand, is SOC’s oil compatible with the one I am using?
Each engine oil formulation is a carefully balanced blend of performance additives and base oils. Accordingly, it is generally safer not to mix different engine oils. However, it is not a problem if you use a mineral oil based engine oil of similar specification for the occasional or emergency top-up. However, we would recommend that the oil is drained out and changed within the next thousand kilometres or so. As a rule of thumb, never mix Synthetic and Mineral oil based lubricants.
My oil consumption has gone up since I changed to SOC oil?
This should not cause undue concern. This rarely happens but, in some cases the introduction of a new oil can result in higher oil consumption, particularly after the first fill with new, higher performance oil. This is typically attributed to the new oil ‘cleaning-up’ the deposits in the piston and ring areas which can lead to a temporary increase in oil consumption. Typically the oil consumption will then drop to its previous level or lower. If high oil consumption persists, this may be an indication of a hardware problem in the engine.
Can shorter oil drains allow me to use a lower quality oil?
Yes, but only true up to a point. For a high output engine operating at, or close to, maximum output, highly stressed parts of the engine need the extra protection offered by a higher performance oil whereas the same engine run at light load can probably operate satisfactorily with a lower performance lubricant.
Is it possible for engine oils to reduce fuel consumption?
Yes – The engine is lubricated by oil that is pumped around by the oil pump to the critical points in the engine where the oil forms a protective film between the moving parts e.g. in the bearings and piston rings/cylinder assemblies. This oil film separates the metal surfaces and reduces friction. By designing and selecting oils that (a) reduce the power required to pump the oil around the engine and (b) minimized friction between the moving parts of the engine, it is possible to minimize the power and friction losses in an engine. Use of quality multi-grade oils will provide 2-3% reductions in fuel consumption compared to mono-grade oils.
My oil pressure is lower than with my old oil?
This could simply be due to using a different viscosity grade. However, this should not cause you to worry. Assuming the oil pressure gauge remains accurate, it is measuring pressure in the oil gallery after the positive displacement oil pump. This pump moves a constant volume of oil at any given engine speed. Assuming that there is no major leakage from, for example, a badly worn main bearing or even oil pump, any variation in pressure is the result of a change in the resistance to the flow of oil meaning that it is easier for the oil to flow to where it is needed and not an indication of lack of oil. In contrast, high oil pressure can indicate either excessive oil thickening resulting in difficulty in pumping the oil to the bearings, or blockages of the oil ways e.g. from deposits formed by breakdown of poor quality oils. This can result in oil starvation and early engine failure.
Can I mix two different types of oil?
Lubricants are always optimized to meet the requirements of international classifications (API, ACEA). However, there are many ways of formulating a specific type of lubricant. Mixing two oils that have equivalent properties will not pose a problem, but final performance cannot be guaranteed. All market oils (petrol engine or diesel, mineral or synthetic) are mixable. However, a blending of two oil qualities lower the superior quality.
Can I use diesel engine oil in a petrol engine, and vice versa?
Petrol and diesel engines have different lubrication requirements. During development, lubricants undergo a number of tests, some common to diesel and petrol engines and others specific to one or the other type, that categorize their performances. At the end of this process, they are awarded an API or ACEA/CCMC compliance standard. These specifications characterize the acceptable functioning of the lubricant in each type of petrol or diesel engine. Lubricants for four-stroke engines usually comply with both petrol and diesel specifications. For example, an API SJ/CF lubricant meets petrol specification SJ and diesel specification CF. But this does not necessarily mean that it will perform in the same way in both petrol and diesel engines.
Can I put in my gear-box the same oil as in my engine?
The answer to this question depends on the technology used. Although some older vehicles allow the same lubricant to be used for both the engine and the gearbox, new vehicles require different products for each. Follow the manufacturer’s recommendations.