*Introduction

Lubricant is a substance that can eventually be liquid in form of water or oil or also can be in the
form of solid which can be graphene or graphite and it is also found in the form of gaseous
substances like air and semi-solid substances like grease. Lubricants and their properties can
very easily be classified based on oil and mineral acceptable oil where most of the lubricant contains
activities that improve the performance where the application has the determination of base oil which
should be used. The types of Lubricants are solid lubricants, liquid lubricants, semi-
solid lubricants, and gaseous lubricants.

The role of a lubricant

The role of a lubricant is to reduce the friction between various substances which are in mutual
contact which ultimately reduces the heat among these surfaces that move simultaneously.
Lubricants can also help the functioning and transmission of foreign particles which can be cooling of
the surface or heating of the surface. Lubricants are very essential and play a very important role in
car engines and reduce wear and tear in this situation. The role of a lubricant in the vehicle sector
is that it cools the hot areas of any engine and the moving parts of the vehicle and the moving parts
of the engine. It also reduces the friction among these engines and the lubricant also improves the
efficiency of the engine which reduces the consumption of the fuel for the vehicle. Lubricants also
protect the mechanical parts of the engine from corrosion which also guarantees long life and
efficiency for the engine. Lubricants also help the engine to be kept very clean and also guarantee a
long life for the engine which helps the engine parts be very clean and good in conditions which
village the imperial it is that occur through the filter of the oil and the changes regarding the oil.
Types of Lubricants

There are various types of lubricants and these are classified in forms of solid lubricants, liquid
Lubricants, semi-solid Lubricants, and gaseous Lubricants. Liquid lubricants include every sort of
mineral, oil, natural ways of liquid that can act as a lubricant. Following that solid Lubricants include
all sorts of lubricants which are in a solid form and are graphite and graphene which have
composites and coatings present in it. Semi-solid lubricants include grease which is generally
present in minerals and vegetable oils and consists of a soap emulsified in it. And lastly,
gaseous lubricants typically include lubricants that are in the form of gas which is air.
Lubricants and their properties
Lubricants and their properties are very essential for any mechanism. One of the most important
properties of lubricants is viscosity which defines the internal resistance of the fluid. Following that
the thermal stability of the lubricant is also determined to be a good property because it refers to the
ability of the lubricants to resist The breakdown regarding high temperatures was stability in the
thermal sector can result in deposits and an increase in viscosity. Oxidation stability is also referred
to as one of the most important properties of any lubricant and refers to the ability of the lubricant to
be resistant in chemical combination regarding oxygen which results in the creation of deposits of
sludge the oxidation stability is accelerated through metal heat and light and acids are formed in
water contamination is done through the lubricants.

Lubricants have several physical properties that

serve their function and performance.
 Viscosity
 Specific gravity and density

 Pour point
 Film strength
 Flashpoint
 Oxidation resistance
 Water separation

 Rust and corrosion protection

Viscosity
The most important property is viscosity. Viscosity, which measures oil’s resistance to
flow, is the most important property of a lubricant. Water has a relatively low viscosity;
molasses has a much higher viscosity. However, if you heated molasses, it would get
thinner. Likewise, oils also get “thinner” as they get hot. Viscosity has an inverse
relationship with temperature. As pressure increases, the viscosity of oil increases, too.
Therefore, the viscosity of oil in service varies with its temperature and pressure.

The viscosity of industrial oils is generally reported at 40˚C. The International Standards
Organization uses this as the standard for its ISO VG grading system that ranges from
ISO VG 2 to ISO VG 1500. The ISO VG is defined as the midpoint of a range that is +
10%. For example, a hydraulic fluid with a viscosity of 31.5 cSt at 40C has an ISO VG of
32. The viscosity of crankcase oils is typically measured at 100C. Lubricating oils can
range from very low viscosity like solvents and kerosene used for rolling metals, to high
viscosity fluids that barely flow at room temperature, such as steam cylinder oils or gear
oils used in sugar mills.

A characteristic of viscosity is the Viscosity Index. This is an empirical number that

indicates the effect of change on the viscosity of a lubricant. A lubricant with high
viscosity index does not thin down very fast as it heats up. It would be used for oils that
are used outdoors in summer and winter. Multi-viscosity engine oils have a high
viscosity index.

Specific Gravity and Density

Specific Gravity – the mass per unit volume of a substance is called density and is
expressed in pounds per gallon, kg/m, or g/cc. The specific gravity is defined as the
density of a substance divided by the density of water. A substance with a specific
gravity greater than one is heavier than water and vice versa. It is a measure of how
well a substance floats on top of water (or sinks below the surface.) Water has a density
of approximately 1 g/cc at room temperature. Petroleum fluids generally have a specific
gravity of less than 1, so they float. Oil slicks float on the surface of a puddle.

Water drains in reservoirs are positioned at the bottom of the reservoir. The lower the
specific gravity, the better the oil floats. Oil with a specific gravity of 0.788 floats very
well. The density of oils decreases with temperature; they float better as they heat up.
Density of petroleum products is often expressed as API gravity which is defined as
Degrees API = (141.5/ Sp Gravity @60˚F – 131.5). The API gravity of water is 10. Since
API gravity is the reciprocal of specific gravity, the higher the API gravity, the lighter the
oil; therefore the better it floats.

Pour Point
The Pour Point of oil is the lowest temperature at which it will pour, or flow, when chilled
without disturbance. The very first additive that was used in engine oil was a Pour Point
depressant additive.

Film Strength
Film strength is a measure of a fluid’s lubricity. It is the load-carrying capacity of a
lubricant film. Film strength can be enhanced by the use of additives. Many synthetic
oils have greater film strength than petroleum oils.
Flash Point
Flashpoint is the temperature at which the vapors of a petroleum fluid ignite when a
small flame is passed over the surface. In order for combustion to occur, there has to be
a certain air/fuel mixture. If there is too much air, the mixture is too lean – there’s not
enough fuel. If there’s too much liquid, it essentially suffocates the flame.

The flashpoint is the temperature where there are enough molecules bouncing around
in the air above the surface to produce an air/fuel mixture that will burn (if there is a
spark to ignite them as evidenced by a popping sound.

The flashpoint is directly related to evaporation rate. A low viscosity fluid will generally
evaporate faster than high viscosity oil, so its flash point is typically lower. For safety, it
is a good idea to choose oil that has a flashpoint of at least 20°F higher than the highest
operating temperature in the equipment. Fire point is the temperature that supports
combustion for 5 seconds.

Oxidation Resistance
Oxidation resistance affects the life of the oil. Turbines and large circulating systems, in
which oil is used for long periods without being changed, must have oils with high
resistance to oxidation. Where oil remains in service only a short time or new oil is
frequently added as make-up, those grades with lower oxidation resistance may serve
satisfactorily.

The rate of oxidation of petroleum oils tends to double for every 18˚F (10°C) rise in
temperature, therefore for every 18˚F(10°C) that you raise the temperature of a system,
expect to change the oil twice as often. Another way of stating this is for every 18˚F
decrease in oil temperature, oil life is doubled.

Water Separation
The separation of oil from water is called demulsibility. Water can cause rust, corrosion
and wear, among many other detrimental factors such as foaming and cavitation. Some
base oils have a natural repulsion to water whereas others are readily miscible. Certain
additives can be used to offset the potential mixing which would lead to emulsification.

Circulating oil systems require oils that demulsify well. Once-through systems do not
require demulsifiers because the oil doesn’t recirculate and collect enough water to
cause rust. Demulsifiers are not necessary if the system is hot enough to boil off any
water such as an engine. In certain instances, oil is mixed with water to improve fire
retardancy or metalworking fluid cooling. Emulsions are important for fire resistance and
metalworking cooling.
 Water/Oil Mixture Partial Separation Full Separation

Rust and Corrosion Inhibiting

When machinery is idle, the lubricant may be called upon to act as a preservative.
When machinery is in actual use, the lubricant controls corrosion by coating lubricated
parts. Once at rest, the lubricant rust and corrosion inhibiting film has now coated the
surface protecting it from water.

Lubricant Chemistry
Lubricants are built with a base oil(s) and additives. Petroleum oils account for most of
the two general categories of industrial and transportation lubrication. They are refined
from crude oil, which, as everyone knows, was formed from billions and billions of tiny
microorganisms that converted over time and pressure to oil. The term hydrocarbon
simply means that it is predominantly comprised of hydrogen and carbon, although
there are small amounts of other elements such as sulfur and nitrogen.

The two principal types of petroleum oils used for lubricants are paraffinic and
naphthenic. When you think of paraffin, you think of wax. That gives you a good idea of
the strengths of paraffinic oil. Wax is an excellent lubricant; it is slippery and quite stable
at high temperatures. It is ineffective at low temperatures because it turns solid. For this
reason, paraffinic oils are recommended for most industrial and transportation
lubricants, except where they run at cold temperatures. Another characteristic of wax is
that it leaves very little residue when it oxidizes, but the small amount of residue is hard
and sticky.

Naphthenic oils are not waxy, so they can be used to very low temperatures. While they
tend to leave more deposits than paraffinic oil, what is left behind is soft and fluffy.
Compressor manufacturers often prefer naphthenic oils because the deposits get blown
out with the compressed air rather than building up on discharge valves. Naphthenic oils
are also used in many refrigeration applications because of their good cold temperature
properties.

Physically, paraffinic oils can be distinguished from naphthenic oils because of their
higher pour points and lower density. Paraffinic oils typically weigh between 7.2 and 7.3
pounds per gallon, while naphthenic oils are slightly heavier. Be careful about
characterizing the base stock of a formulated product based on physical properties
because additives can strongly affect physical properties.

(a) and (b) - Paraffin, (c) - Naphthene, (d) - Aromatic

 With the advent of more sophisticated refining techniques, base stocks have been
categorized into Group I, Group II and Group III. Group I base stocks is conventionally
refined oils. Group II is base stocks that contain greater than 90% saturates and less
than .03% sulfur with a VI between 80-119. They are often produced by hydrocracking.

Satures Conten
Base Oils Sulfur Content Viscosity Index
t
Group I <90 % >0.03 % 80 – 120
Group II >90 % <0.03 % 80-120
Group III >90 % <0.03 % >120
White oils are highly refined petroleum oils that meet food and drug requirements for
direct food contact. Customers may ask that the product be certified as USDA H-1 for
incidental food contact. While the USDA has disbanded the organization that tested and
approved H-1 lubricants for incidental food contact, producers can now self-certify that
their products were formally approved under H-1 or currently meet the requirements set
forth by that standard.

Synthetic Base Oils

Synthetic base oils are produced, mainly, from low molecular weight hydrocarbons, the
process produces high quality and extended service life capability base oils under
extremes operating conditions. In general terms, synthetic base oils are able to handle a
wider range of application temperatures, so they provide the best protection both to high
and low temperatures.

[Text Wrapping Break]

Base
Type of Base
Oils
Group IV Polyalphaolefin
Group V Other Synthetic Bases
[Text Wrapping Break] API Classification (2nd part)

Synthetic Hydrocarbon Fluids

The SHFs comprise the fastest-growing type of synthetic lubricant base stock, they all
are compatible with mineral base stocks.

Polyalphaolefins (PAO) are unsaturated hydrocarbons with the general formula (-

CH2-)n, free of sulfur, phosphorus, metals and waxes. Provide excellent high-
temperature stability and low-temperature fluidity, high viscosity indexes, low volatility
and compatible with mineral base oils. Although the oxidation stability is lower than
mineral oils and their solvency of polar additives is poor, usually PAOs are combined
with other synthetic oils. This base oil is recommended for engine oils and gear oils.
Alkylated Aromatics formed by alkylation of an aromatic compound, usually benzene
or naphthalene. Provide excellent low-temperature fluidity and low pour points, good
solubility for additives, thermal stability and lubricity. Although their viscosity index are
about the same as mineral oils, they are less volatile, more stable to oxidation, high
temperatures and hydrolysis. They are used as the base of engine oils, gear oils and
hydraulic fluids.

Polybutenes are produced by controlled polymerization of butenes and

isobutylenes. Compared with other synthetic base oils they are more volatile, less stable
to oxidation and their viscosity index is lower; their tendency to produce smoke and
shoot deposits is very low so they are used to formulate 2-Stroke engine oils, also as
gear oils combined with mineral or synthetic base oils.

Polyalkylene Glycols (PAG) are polymers made from ethylene oxide (EO), propylene
oxide (PO), or their derivatives. Solubility in water or other hydrocarbon is depending on
the type of oxide. Both provide good viscosity/temperature characteristics, low pour
point, high-temperature stability, high flash point, good lubricity, and good shear
stability. PAGs are not corrosive for most metals and compatible with rubber. The main
disadvantages are low additive solvency and pour compatibility with lubricants, seals,
paints and finishes.

They are used as a base for hydraulic brake fluids (DOT3 and DOT 4) due to their water
solubility, 2-Stroke engine oils due to the low deposits at high temperatures, compressor
lubricants and fire-resistance fluids.
Synthetic Esters are oxygen-containing compounds that result from the reaction of an
alcohol with an organic acid. They have good lubricity, temperature and hydrolytic
stability, solvency of additives and compatibility with additives and other bases.

But some esters can damage seals so they require special compositions. They are used
as base oils for engine oils, mixed with other synthetic bases, because they improve
low-temperature properties, reduce fuel consumption, increase wear protection and
viscosity-temperature properties.

Also, as 2-Stroke engine base oils, they reduce deposit formation, protecting rings,
pistons and sparks. They allow you to reduce the quantity of lubricant from 50:1 of
mineral oils to 100:1 and up 150:1 due to their outstanding lubricity.

Phosphate Esters are used as anti-wear additives due their high lubricity and as base
oils for hydraulic fluids and compressor oils due to their low flammability. But their
hydrolytic and temperature stability and viscosity index is low and their low-temperature
properties are poor. Also, they are aggressive with paints, coats and seals.

Polyol Esters have good high-temperature stability, hydrolytic stability and low-
temperature properties, low volatility and low Viscosity Index; the polyol esters also may
have more effect on paints and cause more swelling of elastomers. To take advantage
of their miscibility with hydrofluorocarbon (HFC) refrigerants, polyol esters are used in
refrigeration systems.

Perfluorinated Polyethers (PFPE) with a density nearly twice that of hydrocarbons, they
are immiscible with most of the other base oils and non-flammable under all practical
condition. Very good viscosity-temperature and viscosity-pressure dependence, high
oxidation and water stability, inert chemically and radiation stable; these properties
joined their shearing stability. They are suitable as hydraulic fluids in spacecraft and as
dielectric in transformers and generators.

Polyphenyl Ethers have excellent high-temperature properties and resistance to

oxidation but they have fair viscosity-temperature properties, they are used as hydraulic
fluid for high temperature and radiation resistance.
Polysiloxanes or Silicones have high viscosity index, over 300, low pour point, high-
temperature stability and oxidation stability so they run well in a wide range of
temperatures; they are chemically inert, non-toxic, fire-resistant, and water repellent,
they have low volatility and are compatible with seals and plastics.

Their disadvantage is the formation of abrasive silicon oxides if oxidation does occur,
effective adherent lubricating films are not formed due to their low surface tension, and
they also show poor response to additives. They are used as brake fluids and as
antifoam agents in lubricants. The table compares different synthetic base oils
properties against mineral oil. Comparison among base oils.

Bio-bases Oils
They are mainly produced from soybeans, rapeseed, palm tree, sunflowers and
safflowers. Their advantages are high biodegradability, superior lubricity, higher flash
point and viscosity index; but their pour point is high and the oxidative stability is poor,
also the recycling is difficult.

Main applications are hydraulic fluids, transmission fluids, gear oils, compressor oils and
greases. Better when application is total loss, indoors or where low pour point is not an
issue, food industry or environmentally-sensitive areas.

Additives

Lubricants require additional ingredients beyond a base oil to provide functionality. The
following is a list of the common materials used. Additives 5% to 30% of an oils formula
with engine oil using the highest concentration.

Typical passenger car engine oil contains detergents, dispersants, rust inhibitors, anti-
wear additives, pour depressants, antioxidants, anti-foam additives and friction
modifiers. Anti-wear additives help reduce wear between heavily loaded engine parts;
detergents and dispersants help prevent buildup of contaminants, sludge, soot and
varnish; and oxidation inhibitors help prevent lubricant breakdown at high operating
temperatures.

Extreme Pressure (EP) Agents – a phosphorus, sulfur, or chlorine-based additive

typically used in gear oils that prevents sliding metal surfaces from seizing under
conditions of extreme pressure. At high local temperatures it combines chemically with
the metal to form a surface film. The EP additives made of sulfur, phosphorus, or
chlorine. They become reactive at a high temperature (160+F) and will attack yellow
surfaces and can be slightly corrosive to some metals, especially at elevated
temperatures.

Antifoam or Foam Inhibitor – silicone-based additives used in turbulent systems, it

helps combine small air bubbles into large bubbles which rise to the surface and burst.
It decreases the surface tension of the bubble to thin and weakens it so that it pops.
Most oils contain foam inhibitors that work by altering the surface tension of the oil. It
allows bubbles to combine and break. Foam inhibitors are either based on silicone or
are organic antifoam agents.

Rust and Corrosion Inhibitors – carbon-based molecules designed to absorb onto

metal surfaces to prevent attack by air and water. Rusting and corrosion work by
slowing the deterioration of a component surface due to a chemical attack by acidic
products of oil oxidation. Rusting refers to the process of a ferrous surface oxidizing due
to the presence of water in oil. Oils that contain rust and oxidation inhibitors are known
as R&O oils in the US, and HL oils overseas.

Oxidation Inhibitors – amine and phenolic antioxidants act by interrupting the free
radical chain reaction that results in oxidation. Essentially, as the oil starts to
decompose in the presence of oxygen, these inhibitors interrupt the reaction. They also
keep metal from speeding up the oxidation reaction by deactivating the metal. Oxidation
inhibitors are added to extend the life of the oil. Oxygen reacts with the oil to produce
weak acids that can pit surfaces. Oxidation inhibitors slow the rate of oxidation.

Oxidation stability is important in most compressor applications because of the heat that
is generated. Oxidized oil can create deposits that build up on discharge valves allowing
them to stick open. This causes hot air to get sucked back into the compression
chamber where it is recompressed. The air can generate enough heat to ignite the
deposits and cause a fire or explosion. Use of synthetics can minimize this possibility.

Anti-wear Additive – Zinc dialkyl dithiophosphate (ZDDP) is the most common anti-
wear additive, although there are many zinc-free additives based on sulfur and
phosphorus that also impart anti-wear properties. The zinc-sulfur-phosphorus end of the
molecule is attracted to the metal surface allowing the long chains of carbons and
hydrogens on the other end of the molecule to form a slippery carpet that prevents
wear.

Not a chemical reaction, rather a super-strong attraction. There are other anti-wear
additives that do not contain zinc. Some are based on sulfur, and some on fatty
materials. Anti-wear additives, as a rule, are not as aggressive as extreme pressure
additives. Oils that contain anti-wear additives are often called AW oils in the US or
carry the HLP designation in Europe. Zinc containing anti-wear oils are generally not
recommended for air compressors because the anti-wear package may compromise the
oxidation stability of the oil.

Demulsifier – carbon-based polymers affect the interfacial tension of contaminants, so

they separate out from oil rapidly. Hydrolytic stability is the ability of the oil to resist
degradation in the presence of water. This is important because any system open to the
atmosphere will be exposed to some moisture from humidity and condensation. Some
ester-based fluids have relatively poor hydrolytic stability and will rapidly turn acidic in
the presence of water.

Pour Point Depressants – chemicals designed to reduce the solidification of the oil to
the lowest temperature at which it will pour under an ASTM laboratory test. Typically,
these are methacrylate molecules and will inhibit the crystallization of the wax
molecules.

Viscosity Index Improvers – chemicals designed to reduce the thinning of an oil when
the temperature increases. These chemicals are typically methacrylate molecules and
will inhibit the thinning of the oil by expanding their molecular footprint this reducing
flowability as the temperature increases.

Detergents – typically used in engine oil formulas, they are designed to keep the
system clean of deposits. Often, they are alkaline by nature thus contribute to increase
then TBN of the oil. Diesel engine lube oils are compounded with alkaline additives to
help neutralize acids from combustion. They also provide antioxidant properties. Typical
compounds contain calcium or magnesium.

Detergents have their disadvantages. Detergents move deposits downstream where

they may build up on heat transfer surfaces in coolers. Detergent oils absorb water. If
water can build up in the oil, it will cause rust and will accelerate oxidation.
Compressors generate water because the humidity from the air condenses as the air is
compressed. It is generally removed in a coalescer or knockout drum, but some water
gets into the oil. For this reason, detergent oils are only used in limited applications.
Dispersants – designed to capture particulates such as soot to form a micelle and keep
in suspension. These compounds can be part of the detergent chemistry or be metal-
free so they can be used in an ashless formulations. Some additives can actually
contribute to wear. Too much metallic detergent/dispersant can leave ash type deposits
that can be abrasive. There is a test to measure the amount of ash left behind when an
oil is burned. It is commonly known as a sulfated ash test. Some engine manufacturers
limit the amount of ash that is in an oil. An “ashless” oil required for some aviation
engines has less than 0.1% ash, while a high ash oil used in some marine engines with
high sulfur fuel can have ash in excess of 1.5%.

Additives can be depleted in service. There is a quick field test used to measure the
level of detergency and dispersant of used oils. It is commonly known as the Oil spot (or
patch) test. A simple test is when oil is filtered through a patch and treated with a
solvent. If particles are concentrated in the center of the patch, it indicates that water or
anti-freeze may be impairing dispersancy. The oil spot test can also pick up fuel soot,
which are particles formed from fuel that is not completely burned. The filter patch can
show evidence of dirt contamination, too.

Compatibility

Lubricant additives were developed to enhance the existing characteristics of the base
oil(s) a lubricant is formulated with, to reduce the deficiencies of the base oils(s) or
impart new performance characteristics. Engine oils were the first lubricants to be
formulated with additives. They have been and still are the largest market segment for
lubrication. So, it is no surprise that most of the research and development efforts have
been placed on engine oil enhancement.

In 1911, the American Society of Automotive Engineers (SAE) established the oil
classification system. This was related only to oil viscosity and not performance. Until
the 1930s, engine oils did not contain any additives. They were only base oils. Prior to
the introduction of additive chemistry, the oil drain intervals were 750 miles. Due to
increasing consumer demands and economic pressures, internal combustion engines
became more sophisticated. Engine oils were becoming increasingly stressed and
challenges on their performance reserves gave rise to a need for additives.

The first oil additive developed was the pourpoint depressant. These acrylate polymers
were developed in the mid-1930s. Anti-wear additives such as zinc dithiophosphate
were introduced in the early 1940s followed by corrosion inhibitors and then sulfonate
detergents. The sulfonate detergents were found to provide acid neutralization as well
as oxidation inhabitation as well as rust and corrosion inhabitation.

In 1932, the American Petroleum Institute (API) established a specification system for
engine oil performance classification. This is an important consideration because it is
the only system by which a lubricant can be deemed compatible with another from a
different manufacturer without the need to test compatibility. As long as the oils are of
the same viscosity grade and have the same API classification and SAE viscosity, the
oils are compatible; the user can mix oils if need be. This is not the case for other
lubricants.

When mixing different lubricants, an adverse reaction may occur between two oils at
certain working conditions in a system. This is considered ‘lubricant incompatibility’.
Most often the cause of incompatibility is the neutralization of an acidic additive in one
oil by an alkaline additive in the other oil. The result is that the additives react with each
other instead of the metal surface, particle or free radicals in the oil.

The newly formed compound becomes ineffective and precipitate (drop out). Most all
additives are polar which is what drives this reaction. This is by design. The polarity
affords surface reaction as well as contamination reactions all that benefit the asset.
During the reaction of incompatibility, often a soap forms that can precipitate a grease-
like gel that interferes with lubrication and oil flow.

However, mixed oils may not always lead to incompatibility issues. They can exist
without precipitation or reaction in an operating system for an indefinite period until
water is introduced. Water can quickly lead to a reaction between the polar additives.
Iron and copper found on the molecular level can act as catalysts in these reactions.
Incompatibility reactions are not reversible. Removing water by drying the system and
the oil does not remove the formed gel or eliminate the soap.
Typically, acidic additives can be found in gear, hydraulic and some circulating oils.
Alkaline-based additives are used in engine oils. There are some additives that are
neither acidic nor basic but neutral, these types of additives are used in compressors
and refrigeration oils. Additives that are acidic are identified as being strong acids and
will react faster than acids that are formed during the initiation stage of oxidation, which
are typically carboxylic acids or nitric acids, and are weak acids due to the limited
number to protons donated.

Weak acids react slower than strong acids. This is the reason why oils that have
incompatible additive chemistry react so fast. Additives are not the only culprit.
Propylene glycols, polyglycols, phosphate esters, polyol esters base oils have fair to
poor compatibility with mineral oil-based lubricants. While these oils may not for solid
substances, they may form a sludge. Many will not mix with the mineral-based
lubricants.

What does the "API" symbol on the engine

oil label mean?
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What does the "API" symbol on the engine oil label
mean?
API is an acronym for American Petroleum Institute which is one of the
organizations that set the engine oil performance standards for each type of vehicle,
both gasoline and diesel engines, in order to certify the qualifications and quality that
meet the requirements to support the engine technology that has been continuously
developed from the past to the present. Most automakers in Thailand and many regions
around the world refer to this API standard to specify the recommended engine oil
quality in the manual for each car model.
The API standard for gasoline engine oils begins with the letter “S” followed by
the English alphabet in ascending order as the standard evolves, starting from API SA
to the latest API SP standard that was introduced in 2020 (2563 B.E.).
The API SP standard has been developed to outperform the previous API SN
and API SN PLUS in almost every aspect. It was designed to support and be suitable
for modern gasoline engines that are rapidly developing, whether reducing engine size
(Engine Downsizing), the use of direct injection fuel system (GDI) or the air
compressing system with a turbocharger. Due to these developments, it is necessary to
have an engine oil that can support these advanced technologies in order to improve
driving performance, engine protection as well as the fuel economy.
So how is the new API SP engine oil superior to the previous AP SN?
With features that have been developed in many aspects, the API SP engine oil
meets the needs of modern gasoline vehicles very well. The advantages of the API SP
are as follows:
 Help prevent severe engine damage from the risk of low speed pre-ignition (LSPI)
that can occur in modern vehicles with direct-injection systems (GDI and Turbo-
GDI).
 Protects the timing chain from wear and elongation in all driving conditions to
maintain the efficiency of the precise valve timing and good performance of the
engine for a long time.
 Helps to control cleanliness of internal engine parts, especially piston and rings.
The ability to prevent sludge and varnish in the engine is better than the previous
standards as well.
 Better heat and oil degradation resistance to support smaller size of engine which
has higher build-up heat in the engine
And today, let PTT Lubricants introduce you to one of the latest engine oils
guaranteed by global standard API SP and ACEA A3/B4-21, PERFORMA SUPER
SYNTHETIC SAE 0W-40 which is a fully synthetic engine oil.
Developed from the existing API SN and ACEA A3/B4-16 standards,
PERFORMA SUPER SYNTHETIC is meant to outperform the previous version in all
aspects, including:
 Superior cleaning power in the engine with the unique innovation of high quality
additives SMART Molecules
 Superior heat and oil degradation resistance to prevent sludge formation and
provide long service life.
 Superior maximum engine protection from starting to high speed and high
temperature
 Superior low-friction engine lubrication with a strong oil film developed on the
EVOTEC Technology platform
 Superior acceleration response and maintaining engine compression for excellent
performance
 Superior environmental friendliness as it helps reduce exhaust gas and carbon
dioxide emission. The PERFORMA SUPER SYNTHETIC is also not harmful to the
exhaust gas treatment equipment.

Therefore, PERFORMA SUPER SYNTHETIC SAE 0W-40 is ideally suitable for

high performance direct injection gasoline engines (GDI/Turbo-GDI) of passenger cars,
sports cars, sport utility vehicles (SUVs), and all gasoline engines with conventional fuel
injection (PFI) that are compatible with unleaded gasoline (ULG) and gasohol (E10, E20
and E85).
 Elevate your driving experience to the next level with PERFORMA SUPER
SYNTHETIC SAE 0W-40, the new formula ‘API SP’ from PTT Lubricants

Some Engine Oils Currently on the Shelves Can Harm Your Engine - Read the
Labels!
There are engine oils currently on the shelves at auto parts stores, gas station convenience
stores, food stores, and other retail outlets that can cause harm to your car’s engine. Yes, you
heard correctly - Cause harm to your car’s engine. These are obsolete engine oils formulated
for use in cars built prior to the 1930s! Know how to read the labels on the front and back of
the bottles of oil you buy or you may be using product that can cause unsatisfactory
performance or harm to your engine.
The service rating of passenger car and commercial automotive motor oils is classified by the
American Petroleum Institute (API). The program certifies that engine oil meets certain Original
Equipment Manufacturer (OEM) quality and performance standards. The service rating is
shown in the API "Service Symbol Donut" on the product label. As shown in the illustration
below, engine oils with an API SA Service Classification were formulated for use in cars built
prior to 1930, and are now obsolete. Yet, there are still not hard to find in retail outlets. Read
on about what you need to read on the labels.

API SERVICE CLASSIFICATION FOR PASSENGER CAR ENGINE

OIL
Read the Labels!

SAE Viscosity Grade

The labels include important information to determine if an engine oil is appropriate for use
in your vehicle. The first piece of information speaks to viscosity grade. The Society of
Automotive Engineers (SAE) defines a numerical system for grading motor oils according to
viscosity. The suffixes (0, 5, 10, 15 and 25) followed by the letter W designate the engine
oil's "winter" grade.

Look to your owner's manual. It specifies the viscosity grade required for your car's engine.
Today, the most common grades are 5W-30.

API Service Categories

Whereas the labeling on the bottle of engine oil may suggest the product is a 5W-30, note, if
there is no "W" between the 5 and the 30 it may not be a 5W-30. As an example, a 5-30 is
not the same as an SAE 5W-30.
The next "code" to look for is the API Service Classification. Although it might appear
complicated to understand at the start, it is really a simple system to get your arms around.
Think of it this way, when cars were first built, the oil they required needed an API SA
Service Classification. From there, it moved to SB, SC, SD, and so on (skipping only SI and
SK).
So if you buy an engine oil meeting only API SA, it's an engine oil formulated for use in
vehicles built in the 1920s. And SA is not hard to find mixed in with SN on the shelves at c-
stores and others. Furthermore, it's also not hard to find SF, SJ and other API Service
Categories on the shelves. Also, don't let price guide you. Engine oils with a Service
Classification prior to SN (including SA) are often priced close to that of API SN.
The service rating of passenger car and commercial automotive motor oils is classified by the
American Petroleum Institute (API). The program certifies that an oil meets certain Original
Equipment Manufacturer (OEM) quality and performance standards. The service rating is
shown in the API "Service Symbol Donut" on the product label.

The labels include two important

pieces of information to determine if an engine oil is appropriate for use in your vehicle. The
first piece of information speaks to viscosity grade. The Society of Automotive
Engineers (SAE) defines a numerical system for grading motor oils according to viscosity.
The suffixes (0, 5, 10, 15 and 25) followed by the letter W designate the engine oil's "winter"
grade.
Look to your owner's manual. It specifies the viscosity grade required for your car's engine.
Today, the most common grades are 5W-30 and 10W-30.

OEM Specific Performance Specifications

Although the majority of vehicles currently on the road in the US specific the use of motor
oils meeting a specific API Service Category, some vehicle manufacturers require use of
lubricants that meet the original equipment manufacturer's (OEM) specifications. General
Motor’s dexos is one example. Click for more about the dexos specification. Always check
the labels on the motor oils purchased to assure they include any OEM specifications
required in your vehicle.
Read the labels on the oils you buy, ask questions when you have your oil changed and read
your car owner's manual.
Always consult your vehicle owner's manual to determine what motor oil you should
use, and READ THE LABELS ON THE OIL YOU BUY.

American Petroleum Institute

Gasoline Engine Oil Service Classifications

Category Status Service

On November 9, 2017, the API Lubricants Standards Group approved the adoption
of SN PLUS, a new classification that may be used in conjunction with API SN
and API SN with Resource Conserving. API began licensing oils against the SN
SN PLUS Current PLUS classification on May 1, 2018. Click for more details.
Introduced in October 2010 for 2011 and older vehicles, designed to provide
improved high temperature deposit protection for pistons, more stringent sludge
control, and seal compatibility. API SN with Resource Conserving matches ILSAC
GF-5 by combining API SN performance with improved fuel economy,
turbocharger protection, emission control system compatibility, and protection of
SN Current engines operating on ethanol-containing fuels up to E85.
SM Current For 2010 and older automotive engines.
SL Current For 2004 and older automotive engines.
SJ Current For 2001 and older automotive engines.
CAUTION - Not suitable for use in most gasoline-powered automotive engines
built after 1996. May not provide adequate protection against build-up of engine
SH Obsolete sludge, oxidation, or wear.
CAUTION - Not suitable for use in most gasoline-powered automotive engines
built after 1993. May not provide adequate protection against build-up of engine
SG Obsolete sludge, oxidation, or wear.
CAUTION - Not suitable for use in most gasoline-powered automotive engines
built after 1988. May not provide adequate protection against build-up of engine
SF Obsolete sludge.
CAUTION - Not suitable for use in gasoline-powered automobile engines built
SE Obsolete after 1979.
CAUTION - Not suitable for use in gasoline-powered automobile engines built
after 1971. Use in more modern engines may cause unsatisfactory performance o
SD Obsolete equipment harm.
CAUTION - Not suitable for use in gasoline-powered automobile engines built
after 1967. Use in more modern engines may cause unsatisfactory performance o
SC Obsolete equipment harm.
CAUTION - Not suitable for use in gasoline-powered automobile engines built
after 1951. Use in more modern engines may cause unsatisfactory performance o
SB Obsolete equipment harm.
SA Obsolete CAUTION - Not suitable for use in gasoline-powered automobile engines built
 after 1930. Use in more modern engines may cause unsatisfactory performance o
equipment harm.

One case study of a lubrication problem and its solution

is the case of a manufacturing company that produced
heavy machinery used in the mining industry. The
company was experiencing frequent equipment
breakdowns, resulting in costly downtime and
maintenance repairs.

After investigation, it was found that the problem was

due to poor lubrication practices. The company was using
a low-quality lubricant, and the maintenance team was
not performing regular oil analysis or changing the oil
frequently enough. As a result, the equipment was not
adequately lubricated, leading to increased friction and
wear.
To solve the problem, the company implemented a
lubrication program that included the following steps:
Selecting a high-quality lubricant that was suitable for the
equipment and operating conditions.
Developing a schedule for oil analysis and oil changes
based on equipment usage and manufacturer
recommendations.
Training the maintenance team on proper lubrication
practices, including how to properly apply the lubricant,
how to check oil levels, and how to monitor equipment
for signs of wear or damage.
Implementing a centralized lubrication system that could
automatically apply lubricant to the equipment at set
intervals, ensuring that the equipment was always
adequately lubricated.
After implementing these changes, the company
experienced a significant reduction in equipment
breakdowns, leading to increased productivity, reduced
maintenance costs, and improved equipment reliability.