Synthetic motor oils are manufactured based on high quality base oils with the addition of an effective additive package. Lubricants of this group are used in modern engines, including in difficult operating conditions.
- Engine oil deciphering (SAE)
- Types of synthetic motor oils by production method
- Hydrocracking oil (HC-synthetic)
- Polyalphaolefin oil (PAO, Full Synthetic)
- Ester oils
- Glycol synthetics
- Areas of application of synthetic motor oils
- Advantages of synthetic oils
- Popular questions about synthetic motor oils
- Can I use synthetic oil after mineral oil?
- Is it true that synthetics are thinner and can seep through the seals?
- If the manufacturer recommends one brand of oil, does using a different brand automatically take the car out of warranty?
Engine oil deciphering (SAE)
The low-temperature viscosity rating means the following:
* 0W- oil is suitable for use in frosty conditions down to -35-30 degrees Celsius. С
* 5W- the oil is suitable for use at frosts down to -30-25 degrees Celsius. С
* 10W- the oil is suitable for use at frosts down to -25-20 deg. С
* 15W- the oil is suitable for use at frosts up to -20-15 deg. С
* 20W- the oil is suitable for use at frosts down to -15-10 deg. С
The high-temperature viscosity rating means the following:
* 30 – the oil is suitable for use in heat up to +20-25 deg. С
* 40 – the oil is suitable for use in heat up to +35-40 deg. С
* 50 the oil is suitable for use in heat up to +45-50 deg. С
* 60 oil is suitable for use in heat up to +50 deg. C and higher
The smaller the number, the “thicker” the oil is, the higher the number, the thicker it is. Thus engine oil 5W-30 may be used at ambient temperature from -30-25 degrees below zero to +20-25 degrees above zero.
Types of synthetic motor oils by production method
Lubricants differ from each other by their composition, which largely depends on the production technology. Unlike mineral oils, which are produced by distillation of crude oil products, synthetics are produced by directed organic synthesis. In the production process a maximum homogeneous molecular composition is obtained in order to increase the operational properties of the oil. The complexity of the technology determines the high price of the product. The cost of synthetic motor oil can be several times higher than that of mineral oil.
Hydrocracking oil (HC-synthetic)
The heavy petroleum base of the material is hydro-treated and deeply refined. Changes take place at a molecular level: crystal structures disappear, macromolecules are broken up into smaller links. Chemical impurities are not removed from the base oil, but modified, obtaining substances with desired properties. Thermal stability is improved, other performance properties are improved, sulfur content is reduced, and the viscosity index is increased. A package of additives helps to get a product with the desired characteristics.
Polyalphaolefin oil (PAO, Full Synthetic)
The product is produced in a complex multistage process of directed synthesis in reactors. Short monomers are used as raw materials. First the base mixture is oligomerized (creating long molecular chains), then double distillation (purification), hydrogenation with catalysts (getting rid of unstable double bonds by saturating them with hydrogen). PAO lubricants compared to hydrocracking ones have a more homogeneous composition and low volatility. The oil change interval is extended while retaining high characteristics.
Lubricants are based on vegetable esters. This is a unique group of oils produced by esterification of alcohols and carboxylic acids. Polar molecules with excess electron density of near-oxygen atoms are obtained. The negatively charged ends of the particles are attracted to the metal surfaces of engine parts and create a stable film. Ester oils are highly environmentally friendly, have good low-temperature, dispersant properties, but are expensive.
There are also glycol synthetics. These are high-performance engine oils with excellent low-temperature properties, but they are incompatible with other types of oils. Therefore, glycol-based materials are almost never produced nowadays.
Areas of application of synthetic motor oils
Synthetic oils are used in modern gasoline and diesel engines of passenger cars, with and without turbocharging, with exhaust aftertreatment system, with particulate filters. The use of synthetic oils is recommended by almost all manufacturers of business class cars. The use of oils in the engines of outdated modifications with high mileage is limited. Improved characteristics of synthetic oils contribute to quick dissolving of deposits and carbon deposits. Contaminations are detached from the surface by large particles and clog the lubrication system.
Advantages of synthetic oils
- High viscosity index. This parameter characterizes the stability of an oil’s properties. Viscosity is measured at different temperatures and its changes are determined by determining the index. The higher the number obtained, the less the oil’s characteristics are subject to fluctuations. Materials with a high viscosity index have a wide temperature range of application, provide a stable film thickness in conditions of extreme heating and cooling, reduce wear of engine parts.
- Low pour point. The parameter defines the moment of the oil viscosity characteristics sharp increase up to complete loss of fluidity. The pour point is caused by the presence of paraffins of normal structure in the liquid. As they cool, they crystallize, clogging all or part of the oil reservoir. In a good synthetic oil, the normal paraffins are removed or chemically transformed into a branched structure to keep the fluid composition uniform. Additives are also added to the materials to lower the pour point. As a result, the grease retains its fluidity when it cools. The oil is able to flow quickly into the engine during cold start-up.
- Low volatility. Natural oil loss occurs during operation. It evaporates, the oil volume decreases, and the concentration of contaminants increases. You have to periodically refill the oil to protect the engine from premature wear. The low evaporation characteristics of synthetic oil increases its efficiency and reduces the cost of refilling.
- Low coefficient of friction. The lubricant creates an oil film on the surface of the contacting parts. It prevents direct friction of structural elements, providing design power, engine efficiency, reducing fuel consumption and increasing unit life. The lower the friction coefficient, the better the sliding and the less the heating.
Popular questions about synthetic motor oils
Can I use synthetic oil after mineral oil?
You can switch from mineral to synthetic oil at any time, but it is recommended to clean the engine with a full flushing fluid beforehand.
Is it true that synthetics are thinner and can seep through the seals?
Not true. If the engine is serviceable and the oil seals are not worn, oil will not leak. Traces of oil often show up on engines with mileage when the seals lose elasticity. You just need to replace them with new ones.
If the manufacturer recommends one brand of oil, does using a different brand automatically take the car out of warranty?
To keep the warranty, it is important to use oil with viscosity and temperature specifications that meet the manufacturer’s recommendations. As a rule, brand requirements are not mandatory. It is also important to consider the season, the region in which the car is used, and the service intervals.