Motor oil has many functions to perform in the engine, but the primary one is to reduce friction between moving parts by separating the mating surfaces with a layer or film of oil. If the oil film is not sufficiently robust to separate the surfaces, they will come into contact with one another and cause wear and possibly irreparable damage. An important indication of the ability of an oil to separate moving surfaces is the viscosity of the oil.

In simple terms viscosity is the “thickness” of a liquid. For example, water will flow more readily than honey. That is because the viscosity of honey is high compared to that of water. We can therefore say that viscosity is an indication of the resistance to flow. In common engineering sense a liquid with a high viscosity will separate surfaces better than one with a lower viscosity. There is however a fine balance between the oil being thick or viscous enough to keep the moving surfaces apart and the oil being fluid enough to be pumped effectively in the engine.

This is complicated by the fact that the viscosity of oil decreases with an increase in temperature and vice versa, therefore the temperature at which viscosity is measured must always be specified. The viscosity of lubricating oil is generally measured at 40⁰C and 100⁰C. The operating temperature of motor oil in modern engines is normally around 100⁰C and therefore the viscosity of engine oil is stipulated at this temperature as shown in the last two columns in the table below:

 

 

 

 

 

 

 

SAE J300 Engine Oil Viscosity Classification

Oils defined by the SAE J300 classification system, cover a single requirement only and are known as monograde oils. The higher the SAE number the thicker the oil. The lower viscosity grades have a “W” (for winter) attached to the number. These oils must also conform to sub-zero viscosity requirements to make them suitable for low temperature applications. If we draw graphs of a typical SAE 15W and SAE 40 monograde oil with viscosity (plotted as a logarithmic function) on the vertical axis against temperature (as a linear function) on the horizontal axis, we come up with the blue and red lines in the diagram below:

 

 

 

 

 

 

 

 

The SAE 15W oil will flow sufficiently at low temperatures to protect engines during startup on cold mornings but will be too thin to provide adequate wear protection at operating temperatures. Contrarily the SAE 40 oil will perform satisfactorily when the engine is hot but will be too viscous to reach moving surfaces swiftly when cold. The solution? An oil that is ‘thin’ when cold but with a viscosity similar to a SAE 40 at operating temperature. To achieve this, we add a viscosity modifier (also known as a viscosity index improver) to the oil.

A viscosity modifier (VM) is an oil additive that is sensitive to temperature. When cold the VM contracts and does not impact the viscosity of the oil. At elevated temperatures it expands to increase the viscosity of the oil. If we start off with a thin oil (for argument’s sake the SAE 15W above) as base and add sufficient VM to meet SAE 40 viscosity limits at 100⁰C we have a SAE 15W-40 multigrade oil.  Similarly there are SAE 5W-30, SAE 5W-40, SAE 10W-40, SAE 20W-50, etc.  multigrade engine oils available in the market. In summary multigrade oils provide better engine protection at low and high temperatures than monogrades because they maintain optimum viscosity over the full engine operating temperature range.

If you have any questions regarding engine oil or any other lubricant related issues, simply mail us at info@bcl.co.za. Our experts are at your disposal and ready to provide you with advice and guidance.

Heat Transfer Fluid or Thermal Fluid is a liquid that partakes in a heat exchange process. It moves heat (thermal energy) from one section of a system to another. Heat transfer fluids are used in countless applications and industrial processes which require heating or cooling – normally in a closed circuit and in continuous cycles. The cooling system of a vehicle is a typical example where the coolant removes heat from the engine and transfers it to the radiator to be cooled down.

Water is the most common heat transfer fluid owing to its low cost, high heat capacity and favorable heat carrying properties. The useful temperature range of water is, however, restricted by freezing at 0⁰C and boiling at elevated temperatures with the actual boiling point depending on the system pressure. For higher temperatures mineral oil is a popular alternative. Probably the most common example of an oil filled heat exchange system is the domestic oil heater.

Oil heaters consist of metal columns with cavities that are filled with the heat transfer oil. A heating element at the base of the heater heats up the oil, which then flows through the cavities of the heater by convection (rising of the hot oil). The heat is transferred through the metal surfaces to the air on the outside. The surface area of the metal columns is large thus allowing lots of air to be in contact with the heater. This permits the heat to be transferred effectively, resulting in a surface temperature which is safe enough to touch.

In larger and industrial thermal fluid systems the oil is circulated with a pump (forced circulation) rather than by convection. Heat transfer systems may be open or enclosed, but almost all large industrial systems are of the closed loop design. This limits oxidation of the oil by preventing it to come into contact with oxygen in the atmosphere. A closed loop system with a single heat source (gas-fired, oil-fired, electric, biomass-fired, etc.) may be used to supply many different heating stations simultaneously and at different temperatures. The heat transfer oil capacity of such large and complex thermal fluid systems can be hundreds of liters and it is therefore essential that the oil should have a long service life. In addition, heat transfer oils must meet a number of other requirements depending on the specifics of the application. Some of the key criteria are:

Low viscosity enables adequate fluidity and promotes heat transmission.
Good heat stability controls oxidation and prevents sludge formation.
High boiling point prevents vaporization at elevated temperatures.
Large thermal capacity enables small volumes of oil to transfer large amounts of heat.
High flash point reduces the risk of fires, particularly in open systems.

Good solvency limits deposit formation and keeps heat exchange surfaces clean.
Low volatility prevents the buildup of pressure in the circulating system.
Noncorrosive formulation protects metal surfaces against rust and corrosion.
Good heat conductivity ensures effective heat transfer between oil and heat exchange surfaces.

To meet these requirements good quality mineral based heat transfer oils are formulated with highly refined base stocks and are compounded with functional additives to enhance the performance of the final product. As a rule of thumb adherence to the following temperature guidelines will ensure long service of mineral based heat transfer oils in thermal systems with forced circulation:

All it takes to keep your thermal system operating trouble-free are a few quick maintenance steps and the correct heat transfer oil. Making the right choice will enhance efficiency and increase the life of your heat transfer system. To help you make the best decision, simply mail us at info@bcl.co.za. Our experts are at your disposal and ready to provide you with advice and guidance.

We would also like to make use of this opportunity to wish all our readers, customers and followers a wonderful Festive Season and a prosperous New Year. We are certainly looking forward to chat to you again in 2022.

A chainsaw is a portable, mechanical saw which cuts material with a set of teeth attached to a rotating chain that runs along a guide bar. Chainsaws are primarily used for wood cutting activities, such as tree felling, pruning and harvesting firewood. Chainsaws with specially designed bar and chain combinations have also been developed for special applications, such as cutting concrete during construction projects.

The origin of the chainsaw is debatable, but a chainsaw-like tool was made around 1830 by Bernard Heine, a German orthopedist. This instrument, the osteotome, had a chain with small cutting teeth on the chain links. The chain was moved around a guiding blade by turning the handle of a sprocket wheel. As the name implies, the tool was used to cut bone during medical procedures.

Most chainsaws are driven by petrol engines, although some models have electric motors powered by a battery or electric power cord. Petrol driven chainsaws are fitted with two-stroke engines since they do not require an oil sump like four-stroke petrol engines. The traditional lubrication method of mixing oil with the petrol of two-stroke engines allows it to work in any orientation, as there is not an oil reservoir that is dependent on gravity. This is an essential property for chainsaws because they are required to operate at any angle.

Engine emission standards have become more stringent over the last few years. To meet these standards modern chainsaw engines are designed to run on leaner oil/petrol ratios than older models. The result is that they run hotter.

Lower quality two-stroke oils may not be adequate to provide satisfactory protection at these elevated temperatures. Furthermore, substandard oils do not have sufficient lubricating properties and will also leave carbon residues on pistons, cylinders and exhaust ports. This causes decreased engine performance and premature failure of vital engine components. To ensure a long, trouble-free life of a modern two cycle engine, it is essential to use the quality oil recommended by the chainsaw manufacturer. For more information about two-stroke engine lubrication please refer to OilChat numbers 44 to 46.

As a rule of thumb, most two-stroke engines these days use a 50:1 fuel/oil mix. This is a mixture of 2% oil in the petrol and is equivalent to 100ml of oil in 5L of petrol. Older chainsaws and larger

models (with engine capacity generally 70 cc and more) may well require higher oil ratios and the engine manufacturer’s recommendations should always be followed. When mixing the oil and petrol use a clean airtight container intended for fuel. Not only will it prolong the shelf life of the fuel mix, but it can also help prevent spillage, permeation and evaporation.

Equally important is the lubrication of the chain and bar. Without proper lubrication the working life of these critical components will be drastically reduced. The chain and bar of almost all saws are self-lubricating. They have an oil reservoir that feeds the lubricant automatically to the bar and chain when the machine is used. If a chainsaw is operating slower than normal, or the fuel tank runs dry much quicker than it should, chances are quite good that you need to add chain bar oil – and quickly. The bar and the chain run in constant contact with each other. Without lubrication, a lot of friction that could do major damage to the chainsaw, is generated.

To be effective a chain bar oil must control wear, protect against rust and corrosion and resist throw-off. To provide the desired lubricating qualities under all operating conditions, chain bar lubricants are formulated with highly refined base oils of suitable viscosity, anti-wear and/or extreme pressure additives, rust and corrosion inhibitors and tackiness agents. Anti foam additives, pour point depressants and solid lubricants may also be included in the oil formulation if required.

Finally, if the chainsaw features a sprocket at the front end of the chain guide bar, add some grease to that as well. Simply use a grease gun to give it a couple of  shots of clean, high-quality general-purpose grease but remember to clean the lubrication hole first. Once the grease begins pushing out, stop and wipe the outside of the sprocket clean.

All it takes to keep your chainsaw running for years to come are a few quick maintenance steps and the correct lubricants. If you have any questions regarding chainsaw lubrication or any other lubricant related issues, simply mail us at info@bcl.co.za. Our experts are at your disposal and ready to provide you with advice and guidance.

This newsletter is in response to feedback from our readers. Following OilChat #13 we have received requests to elaborate on the composition and application of automotive gear oils; API GL-4 and GL-5 in particular. The most frequent question that comes up is “Can GL-5 gear oils be used in vehicles with synchronized manual transmissions?”

Modern high performance automotive gear oils (API GL-4 and GL-5) are formulated with oxidation and rust inhibitors, antifoam agents, pour point improvers and extreme pressure (EP) additives.The most common EP additives are sulfur-phosphorus (S-P) compounds that adhere to metal surfaces through polar attraction.

When subjected to heat and/or pressure (from a collapsing lubricant film) they react chemically with the metal surface to form a tough EP film. In general, the higher the GL rating, the higher the S-P content and the higher the EP protection provided.

Traditionally the engines of motor vehicles were placed in the front with a long driveshaft transmitting power to the wheels at the back – see Figure 1 below. A differential is used to let the power from the driveshaft make a 90 degree turn so it can get to the wheels via the side shafts (axles) – Figure 2. In days gone by vehicles were designed quite high on their wheels and the position of the driveshaft was not an issue. A crown wheel (large gear) and pinion (small gear) are used in the differential to ‘bend’ the power from the driveshaft to the side shafts (Figure 3). In this configuration the axis (center) of the pinion is on the same level as that of the crown wheel.  This design, however, became a problem when the height of vehicles was reduced to make them more streamline, since lots of interior space had to be sacrificed to accommodate the driveshaft tunnel – that hump that runs from the front to the rear in the floor of the vehicle. This problem was reduced with the introduction of hypoid differentials where the axis of the pinion is set below the axis of the crown wheel (Figure 4), resulting in a lower driveshaft.

 

Generally a differential with the axis of the pinion on the same level as that of the crown wheel (Fig 3) will be adequately lubricated by an API GL-4 oil although GL-5 will provide better protection.  Today, however, most rear wheel drive vehicles are fitted with hypoid differentials (Fig 4). Because of the increased sliding contact between hypoid gears, their contact pressure is higher and API GL-5 oils are required to lubricate these diffs effectively.

Most API GL-5 oils correctly claim they meet GL-4 requirements but does that make them suitable for synchromesh or synchronized transmissions? The answer is NO! They meet API Gear Oil specifications, not transmission oil requirements. The API GL-4 and GL-5 categories do not mention anything about transmission oil requirements, synchronized transmission in particular.

Synchronized transmissions are fitted with synchronizers to allow light and easy gear shifting and to eliminate that grinding sound, particularly when changing to a lower gear. Synchronizers use friction to match the speed of the components to be engaged during shifting. Slippery lubricants such as GL-5 hypoid gear oils can reduce the friction between the mating synchronizer surfaces and thereby effecting synchronizer operation negatively. In addition, synchronizers are often made of copper alloys. The way in which EP additives work can be disastrous to these ‘soft’ alloys. The S-P may attack the yellow metals chemically, causing synchronizers to fail prematurely.

Another question is why API Category GL-6 is obsolete when it offers protection from gear scoring in excess of that provided by API GL-5 gear oils? To answer this question we need to take a trip down memory lane.  Many years ago Ford required improved protection in certain of their pickup trucks and about the same time General Motors introduced a differential with a very high pinion offset.

This necessitated a higher gear oil service category and API GL-6 was developed to provide the greater protection needed. In fact the GM differential was used in the GL-6 test procedure. This level of protection is still claimed by some oil manufacturers, but can no longer be tested since GM have stopped producing these diffs. A shift to more modest pinion offsets and the obsolescence of API GL-6 test equipment have greatly reduced the commercial use of API GL-6 gear lubricants. Nevertheless, some manufacturers of high performance cars still specify this level of EP performance for their vehicles.

The photo on the left shows a brass synchronizer that had been damaged to such an

extent that it no longer “grips” its mating surface.  API GL-4 lubricants contain about half the S-P additives of their GL-5 counterparts. This means they do not react with synchronizers quite as aggressively but then they provide less wear protection for transmissions. This nonetheless is not a serious problem since there are no hypoid gear arrangements in synchronized transmissions.

What is then used in the transaxles of front wheel drive vehicles where the transmission and differential are combined in one unit? Oil selection is in

fluenced by the transaxle design:

1. Contact surfaces of the gears are big enough to carry the load and less protection is required from the lubricant.
2. Most transaxles are designed without hypoid gears.

Another question is why API Category GL-6 is obsolete when it offers protection from gear scoring in excess of that provided by API GL-5 gear oils? To answer this question we need to take a trip down memory lane.  Many years ago Ford required improved protection in certain of their pickup trucks and about the same time General Motors introduced a differential with a very high pinion offset. This necessitated a higher gear oil service category and API GL-6 was developed to provide the greater protection needed. In fact the GM differential was used in the GL-6 test procedure. This level of protection is still claimed by some oil manufacturers, but can no longer be tested since GM have stopped producing these diffs. A shift to more modest pinion offsets and the obsolescence of API GL-6 test equipment have greatly reduced the commercial use of API GL-6 gear lubricants. Nevertheless, some manufacturers of high performance cars still specify this level of EP performance for their vehicles.

In addition to API GL specifications, synchronized transmissions and limited slip differentials often have specific frictional requirements and reference should always be made to the equipment manufacturers’ oil recommendations for these units.

The API (American Petroleum Institute) defines automotive gear lubricant service designations to assist manufacturers and users of automotive equipment in the selection of transmission, transaxle and axle lubricants based on gear design and operating conditions.

Selecting a lubricant for specific applications involves careful consideration of the operating conditions and the chemical and physical characteristics of the lubricant. The API designations also recognize the possibility that lubricants may be developed for more than one service classification.

Gear oils are classified by the API using the letters GL (abbreviation for Gear Lubricant) followed by a number to identify the performance level of the oil. The API has also issued the MT-1 service designation for certain non-synchronised manual transmissions. Only three of the seven automotive gear lubricant service designations issued by the API are currently in use due to changes in manufacturers’ recommended practices or due to the unavailability of testing hardware.

The API Lubricant Service Designations for Automotive Manual Transmissions, Manual Transaxles, and Axles are described below, followed in some instances by supplemental comments (in italics) regarding the use of these lubricants:

API GL-1 (Obsolete)

This designation denotes lubricants intended for manual transmissions operating under such mild conditions that straight petroleum or refined petroleum oil may be used satisfactorily. Oxidation and rust inhibitors, antifoam agents and pour depressants may be added to improve the characteristics of these lubricants. Friction modifiers and extreme pressure additives shall not be used.

API GL-1 lubricants are generally not suitable for most passenger car manual transmissions. However, these
oils may be used satisfactorily in some truck and tractor manual transmissions. Lubricants meeting service designation API MT-1 are an upgrade in performance over lubricants meeting API GL-1 and are preferred by commercial vehicle manual transmission manufacturers.

API GL-2 (Obsolete)

The designation API GL-2 denotes lubricants intended for automotive worm-gear axles operating under such conditions of load, temperature, and sliding velocities that lubricants satisfactory for API GL-1 service will not suffice. Products suited for this type of service contain anti-wear or film-strength improvers specifically designed to protect worm gears.

 

API GL-3 (Obsolete)

This designation denotes lubricants intended for manual transmissions operating under moderate to
severe conditions and spiral-bevel axles operating under mild to moderate conditions of speed and load. These
service conditions require a lubricant having load-carrying capacities exceeding those satisfying API GL-1 service
but below the requirements of lubricants satisfying API GL-4 service.

Gear lubricants designated for API GL-3 service are not intended for axles with hypoid gears. Some transmission
and axle manufacturers specify engine oils for this service.

 API GL-4 (Current)

The designation API GL-4 denotes lubricants intended for axles with spiral bevel gears operating under moderate
to severe conditions of speed and load, or axles with hypoid gears operating under moderate conditions of speed
and load. Axles equipped with limited-slip differentials have additional frictional requirements that are normally
defined by the axle manufacturer.

API GL-4 oils may be used in selected manual transmission and transaxle applications where API MT-1 lubricants
are unsuitable. In all cases, the equipment manufacturer’s specific lubricant quality recommendations should be
followed.

API GL-5 (Current)

This designation denotes lubricants intended for gears, particularly hypoid gears, in axles operating
under various combinations of high-speed/shock load and low-speed/high-torque conditions. Frictional requirements for axles equipped with limited-slip differentials are normally defined by the axle manufacturer.

API GL-6 (Obsolete)

The designation API GL-6 denotes lubricants intended for gears designed with a very high pinion offset. Such
designs typically require protection from gear scoring in excess of that provided by API GL-5 gear oils.

A shift to more modest pinion offsets and the obsolescence of original API GL-6 test equipment and procedures have eliminated the commercial use of API GL-6 gear lubricants.

API MT-1 (Current)

This designation denotes lubricants intended for non-synchronized manual transmissions used in buses
and heavy-duty trucks. Lubricants meeting the requirements of API MT-1 service provide protection against the
combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-4 or GL-5.

API MT-1 does not address the performance requirements of synchronized transmissions and transaxles in
passenger cars and heavy-duty applications.

Automatic or semi-automatic transmissions, fluid couplings, torque converters, and tractor transmissions usually require special lubricants. Consult the equipment manufacturer or your lubricant supplier for the proper lubricant for these applications.

The API Automotive Gear Oil Classifications only specify performance level and service designation. Viscosity limits for automotive gear lubricants are described by the SAE J306 standard as discussed in OilChat #4.

The ACEA Oil Sequences describe, amid others, “E” category service-fill oils for heavy duty diesel engines. These sequences define the minimum performance level for engine oils to meet ACEA requirements. Performance parameters other than those covered by the sequences or more stringent limits, may be specified by individual engine manufacturers – hence OEM specifications such as Mercedes-Benz 228.3, Volvo VDS-3, etc.

The ACEA Oil Sequences are subject to constant development to stay abreast of new engine designs, the increasing use of biofuels and more stringent emission requirements.

Each new issue of the sequences may exclude a previous sequence or include a new one, incorporate an increase in severity for an existing sequence or a change in testing method. As new editions are published older editions are withdrawn. The table below summarises the changes that have occurred since the first ACEA Oil Sequences were introduced in 1996.

 

ACEA intentionally omitted “E8” from the sequences.

A change in year linked to a specific sequence (i.e. E4-99 to E4-07) in the table above indicates a change in the sequence requirements. The four current ACEA Oil Sequences for heavy duty diesel engines are described below followed by a brief outline of the relevance of the sequence in italics:

E4 Stable, stay-in-grade oil providing excellent control of piston cleanliness, wear, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV and Euro V emission requirements and running under very severe conditions, e.g. significantly extended oil drain intervals according to the manufacturer’s recommendations. It is suitable for engines without particulate filters, and for some EGR (Exhaust Gas Recirculation) engines and some engines fitted with SCR NOx (Selective Catalytic Nitrogen Oxides) reduction systems.

UHPD (Ultra High Performance Diesel) category and the highest level of engine oil performance in the global heavy duty diesel market. Mostly SAE 10W-40 formulated with Group III base oils. Extended drain oils suitable for use in vehicles without a DPF (Diesel Particulate Filter). 

E6 Stable, stay-in-grade oil providing excellent control of piston cleanliness, wear, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV, Euro V and Euro VI emission requirements and running under very severe conditions, e.g. significantly extended oil drain intervals according to the manufacturer’s recommendations. It is suitable for EGR engines, with or without particulate filters, and for engines fitted with SCR NOx reduction systems. Designed for use in combination with low sulphur diesel fuel.

UHPD category and the highest level of engine oil performance seen in the global heavy duty diesel market. Mostly SAE 10W-40 formulated with Group III base oils. Extended drain low SAPS oils suitable for use in vehicles with or without a DPF.

E7 Stable, stay-in-grade oil providing effective control with respect to piston cleanliness and bore polishing. It further provides excellent wear control, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV and Euro V emission requirements and running under severe conditions, e.g. extended oil drain intervals according to the manufacturer’s recommendations. It is suitable for engines without particulate filters, and for most EGR engines and most engines fitted with SCR NOx reduction systems.

SHPD (Super High Performance Diesel) tier of mainly SAE 15W-40 engine oils designed for use in medium severity operations. Suitable for use in vehicles without a DPF. Often combined with API CI-4. 

E9 Stable, stay-in-grade oil providing effective control with respect to piston cleanliness and bore polishing. It further provides excellent wear control, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV, Euro V and Euro VI emission requirements and running under severe conditions, e.g. extended oil drain intervals according to the manufacturer’s recommendations. It is suitable for engines with or without particulate filters, and for most EGR engines and for most engines fitted with SCR NOx reduction systems. Designed for use in combination with low sulphur diesel fuel.

SHPD tier of mainly SAE 15W-40 engine oils designed for use in medium severity operations. Suitable for use in vehicles with and without a DPF. Often combined with API CJ-4. 

Claims against the ACEA Oil Sequences can be made on a self-certification basis. ACEA, however, requires that any claims for oil performance relating to these sequences must be based on credible data and controlled tests in accredited test facilities.

It is expected that new ACEA Oil Sequences will be issued during the third quarter of 2016. ACEA 2016 marks the first update since 2012, a break from the specification’s typical biennial update schedule. So what are some of the sequence changes that we can expect to see in ACEA 2016?

Biofuels. New fuel alternatives are becoming increasingly prominent, particularly the use of biodiesel fuels for the heavy duty market. These fuels can lead to increased oxidation, degradation and thickening of the oil. ACEA 2016 may therefore include new tests to assess lubricant effectiveness to prevent oxidation and deposit formation.

Seal Materials. Modern engines have introduced new elastomer sealing materials, necessitating an update of the seal test methods in ACEA 2016.

Soot. A new test may possible be added to assess oil resistance to soot-related thickening and deposits in diesel engines. The expected test will reflect the cleaner operation of modern low-soot heavy duty diesel engine oils.

In summary, modern diesel engines are being forced to become more fuel efficient, less polluting, and longer lasting. Subsequently their lubrication needs have changed dramatically since 2012. In addition, oil change intervals are being extended and the use of biodiesel is increasing. These changes require the use of superior heavy duty diesel engine oils. ACEA 2016 is expected to address all these issues and it is therefore not surprising that its pending release is anticipated globally with great interest.

Oil Chat will keep you UpToDate.

Always consult your vehicle owner’s manual to determine what engine oil you should use, and READ THE LABELS ON THE OIL YOU BUY.

ACEA is the abbreviation for the Association des Constructeurs Européens d’Automobiles or the European Automobile Manufacturers’ Association in English. Among many other activities ACEA defines specifications for engine oils on behalf of the major vehicle manufacturers in the European Union.

The ACEA Oil Sequences were introduced in 1996 when they superseded the former CCMC (Committee of Common Market Automobile Constructors) specifications for engine oils. The ACEA Oil Sequences are the European counterpart of the API Engine Oil Classification System.

There are three principal categories within the ACEA Oil Sequences – “A/B” for petrol and light duty diesel engine oils, “C” for light duty catalyst compatible oils and “E” for heavy duty diesel engine oils. In this issue of OilChat the ACEA Oil Sequences for petrol and light duty diesel engines will be discussed. However, before this is done a few terms that are used in describing the Sequences need to be explained:

SAPS:	(Sulphated Ash, Phosphorus, Sulphur) Phosphorus and sulphur comprise a significant portion of the additive content of engine oil. Sulphated ash is not added to oil; it is the result of additives in the oil leaving an ash residue when the oil is burnt under prescribed laboratory conditions.
DPF:	(Diesel Particulate Filter) A device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.
TWC:	(Three Way Catalyst) A catalytic converter that reduces the harmful Nitrogen Oxides, Carbon Monoxide and Unburned Hydrocarbons in the exhaust gas of (mainly petrol) engines.
HTHS:	(High Temperature/High Shear rate viscosity) HTHS is indicative of the resistance of engine oil to flow in the tight tolerances between fast moving components in hot engines. It influences fuel consumption and wear in high shear regimes in an engine, such as those existing in piston ring/cylinder wall interface and the valve drive train. Lower HTHS viscosity generally means thinner oil which can improve fuel economy. Lower HTHS viscosity, however, usually comes at the expense of wear protection and therefore low HTHS oils are not suitable for use in all engines.

The current ACEA Oil Sequences were introduced in 2012 and may be condensed as follows:

ACEA A/B : Petrol and diesel engine oils

A1/B1 Fuel efficient oil for use at extended drain intervals in petrol and light duty diesel engines designed to use low friction, low viscosity and low HTHS oils. Unsuitable for use in some engines.

A3/B3 Intended oil for use in high performance petrol and light diesel engines and for extended drain intervals where specified by the engine manufacturer.

A3/B4 Intended for use in high performance petrol and direct injection diesel engines, but also suitable for applications described under A3/B3.

A5/B5 Fuel efficient oil for use at extended drain intervals in high performance petrol and light diesel engines requiring low friction, low viscosity and low HTHS oils. Unsuitable for use in some engines.

ACEA C : Catalyst compatibility oils

C1 Fuel efficient oil intended for vehicles with DPF and TWC. Formulated for high performance petrol and light diesel engines requiring low friction, low viscosity, low SAPS and low HTHS oils. These oils have a SAPS limit of 0.5% and are unsuitable for use in some engines.

C2 Fuel efficient oil intended for vehicles with DPF and TWC. Formulated for high performance petrol and light diesel engines designed to use low friction, low viscosity and low HTHS oils. These oils have a SAPS limit of 0.8% and are unsuitable for use in some engines.

C3 Fuel efficient oil intended for vehicles with DPF and TWC. Formulated for high performance petrol and light diesel engines designed to use low HTHS oils. These oils have a SAPS limit of 0.8% and are unsuitable for use in some engines.

C4 Fuel efficient oil intended for vehicles with DPF and TWC. Formulated for high performance petrol and light diesel engines requiring low SAPS and low HTHS oils. These oils have a SAPS limit of 0.5% and are unsuitable for use in some engines.

Note: Oils with a 0.8% SAPS limit may be referred to as mid SAPS.

To meet the stringent requirements of the above ACEA Oil Sequences, engine oils must pass fourteen laboratory and ten engine tests. Hence oils that conform to these ACEA standards are formulated with superior additive packages – even more so when the oil needs to meet API requirements as well. For instance, a well formulated engine oil can conform to ACEA A3/B4/C3 as well as API SM/SN. It is, however, not always possible for an oil to meet both ACEA and API standards. To illustrate, it is unattainable for an ACEA A5/B5/C1 performance level oil to meet API SM/SN, because A5/B5/C1 requires a maximum phosphorus limit of 0.05% whilst SM/SN specifies a minimum level of 0.06%.

Since the first ACEA Oil Sequences were introduced in 1996 new specifications were issued in 1998, 1999, 2002, 2004, 2007, 2008, 2010 and 2012. It is therefore obvious that the next issue of the ACEA Oil Sequences is now long overdue. Reasons for this delay are the replacement of obsolete tests with new ones to reflect engine technology advancements and also to address the complications associated with the increasing use of biofuels. It is expected that the new sequences will be issued during the second half of 2016 and that the new release may, among other changes, comprise the removal of A1/B1 and the introduction of a C5 category.

The ACEA Oil Sequences represent some of the most significant performance standards of the lubricant industry. Their influence and importance extend beyond Europe and since the pending update is a major step for the global lubricant industry, it is anticipated with great interest.

In conclusion it should be mentioned that ACEA itself does not test or approve any oils. They set the standards and oil manufacturers are responsible for having their oils tested in accordance to the prescribed standards. They may then make performance claims for their products, provided such products satisfy the relevant ACEA requirements.

Always consult your vehicle owner’s manual to determine what engine oil you should use, and READ THE LABELS ON THE OIL YOU BUY.

Q8Oils’ state-of-the-art blending plant in Antwerp is one of the largest and most technically advanced lubricant production facilities in Europe. With a multi-million Euro investment just completed, the plant has a blending capacity which is scalable up to 250 million liters per annum.

With 24 base oil and 42 additive tanks respectively, the plant can efficiently produce the widest range of finished lubricant products of any blending plant in Europe. Furthermore the mega-blend vessel at Q8Oils’ Antwerp blending plant can manufacture batches up to 400,000 liters.

 

Q8Oils is a subsidiary of the Kuwait Petroleum Corporation (KPC), one of the world’s largest oil producers. Supported by KPC’s significant resources, Q8Oils is a leading global lubricants supplier. Q8Oils offers one of the most comprehensive ranges of lubricants in the industry, with a portfolio of more than 1,000 different products to suit every application from the smallest consumer to the largest machines.

Q8Oils product innovation and exceptional quality are achieved by combining the latest additive technologies with superior base oils. This is supported by O8Oils Antwerp plant’s stringent in-house quality control procedures and world-class technical development capabilities that are complemented by ISO 9001, ISO 14001 and RC 14001 certification.

To find out more about the plant go to our homepage, click on the NEWS tab and open Kuwait Petroleum’s Q8Oils opens its state-of-the-art Blending Plant in Antwerp.

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The American Petroleum Institute (API) Engine Oil Licensing and Certification System provides a simple designation of letters and numbers that allows engine manufacturers and oil marketers to provide users with the information they need to ensure that the proper oil is selected for an engine.

Each letter/number designation identifies a service category (e.g. CI-4) which is linked to a series of tests that the oil must pass before it is allowed to carry that designation. The API “S” series describes oil standards for petrol engines (see OilChat #8) while the API “C” series defines oil standards for diesel engines as summarised in the table below:

 

One of the reasons for the obsolescence of the older categories is a lack of facilities and parts to run some of the key engine tests required for qualification. API Oil Service Categories CA, CB and CC should no longer be used in diesel engines unless specifically recommended by the equipment manufacturer.

 

API released the ‘intermediate’ category CI-4 Plus during 2004 as corrective action to tweak CI-4 since these oils were not performing as they were originally intended to do in all applications.  CI-4 PLUS closes a small but very real gap between the expected conditions of 2002 low-emission engines and what was actually taking place in the real world.

 

By consent decree engine manufacturers were required to comply with the US Environmental Protection Agency (EPA) emission standards set for 2004 as early as from October 2002, 15 months ahead of the scheduled date. As a result, both engine manufacturers and lubricant formulators had to alter their product development timelines drastically. In fact the CI-4 category was only finalized in December 2001, a mere ten months before the revised introduction date of the new low-emission engines. That created a situation where 2002 engines were being designed and developed parallel to the oil, rather than in sequence. Actually CI-4 was the first oil to be developed without engines being available to test prototype oils. Although CI-4 proved to be generally effective, oil companies and engine OEMs found that in some instances the soot being generated by cooled Exhaust Gas Recirculation (EGR) was much higher than expected. In addition, it was practically a different kind of soot that thickened the oil much more rapidly. A few OEM’s also discovered that certain engines required better oil shear stability than that specified by CI-4. Consequently CI-4 oil formulations had to be adjusted to handle what was happening out in the field and API CI-4 Plus was introduced in 2004.

 

 

CI-4 Plus was designed to offer better viscosity control, greater soot loading capability and improved shear stability. Another benefit of CI-4 PLUS is its potential to extend oil drain intervals. However, CI-4 PLUS oils come with a price premium over CI-4 and therefore CI-4 PLUS only benefits a limited percentage of the market. API CI-4 Plus was superseded in 2006 by CJ-4 oils with additive systems specially designed to improve the protection of both the engine and advanced emissions control systems.

 

API is scheduled to introduce two new diesel engine oil categories late 2016 / early 2017. These are API CK-4 and API FA-4.  This is the first time since 1994 that an API diesel engine oil standard has been split into two categories. Part of the impetus for this deviation stems from U.S. EPA regulations to reduce greenhouse gas (GHG) emissions and improve fuel economy for diesel engines. The new categories are created to address these mandates, enabling new advancements in diesel engine design, improving fuel economy through the use of lighter viscosity oils and enhancing engine durability through improved additive chemistry, as well as base oil selection.

Performance criteria for API CK-4 and FA-4 are summarized below:

API CK-4 describes oils for use in high speed four-stroke diesel engines designed to meet 2017 model year on-highway and Tier 4 off-road exhaust emission standards, as well as for previous model year diesel engines.

 

API FA-4 describes certain XW-30 oils specifically formulated for use in on-highway, high speed four-stroke diesel engines designed to meet 2017 model year on-highway greenhouse gas (GHG) emission standards.

Finally it should be mentioned that it is possible for engine oil to conform to both API diesel and petrol standards. It is common that diesel rated engine oils carry “corresponding” petrol specifications. For example, API CJ-4 oils will almost always list either SL or SM, while API CI-4 will normally conform to SL and API CH-4 oils will usually meet SJ, etcetera.

Always consult your vehicle owner’s manual to determine what motor oil you should use, and READ THE LABELS ON THE OIL YOU BUY

 

 

In the early days of the automobile, engine oils were classified by viscosity grade only. By 1930 vehicle manufacturers, however, recognised that there was a need for fixed standards of lubricant quality so that cars and trucks could be sold anywhere world-wide without major modifications or embarrassing failures.

The American Petroleum Institute (API) then took on the task of setting standards for engine oil. Their first attempt described three oil categories: Regular (straight mineral oil); Premium (mineral oil with oxidation inhibitors) and Heavy Duty (mineral oil with oxidation inhibitors and detergents/dispersants).

However it was soon realised the requirements for petrol and diesel engines were different and the next API engine oil classifications defined categories for petrol (ML, MM, MS) and diesel (DG, DM, DS) engine oils.

Since then the API Engine Oil Classifications have been revised and updated on various occasions to accommodate improvements in engine designs and the ever increasing stresses placed on engine oil, and more recently to address the concern over the environmental impact of engine emissions. Currently the system includes classifications for spark ignition/petrol engines (“S” series) and for compression ignition/diesel engines (“C” Series). Following is the complete classification for petrol engine oils:

CATEGORY	STATUS	SERVICE
SA Before 1930	Obsolete	Category for such mild service that these oils required no additives. Originally these oils were classified “API Regular”.
SB 1930	Obsolete	Formulated to provide some antioxidant and anti-scuff properties. Because this category contained no detergent additives, they were also called “non-detergent” oils.
SC 1951	Obsolete	This category provided improved protection against low temperature sludge, deposits, rust, corrosion and wear. Previously known as “API MS”.
SD 1967	Obsolete	Engine tests for this classification also included testing the cleanliness of the positive crankcase ventilation valves during short trips and stop-and-go driving.
SE 1971	Obsolete	Oils designed for this service provided more protection against oil oxidation, high temperature engine deposits as well as rust and oxidation.
SF 1979	Obsolete	Provided improved oxidation stability and anti-wear performance. These oils also offered better protection for smaller, higher revving engines operating at higher temperatures.
SG 1988	Obsolete	Oils meeting this service category provided better control of engine wear, oil oxidation, sludge and varnish for improved engine cleanliness
SH 1993	Obsolete	These oils offered better protection than previous categories in the areas of deposit control, oil oxidation, wear, as well as rust and corrosion.
SJ 1996	Current	This category exhibited different evaporation loss characteristics, plus meeting the requirements of bench tests for wet filterability, gelation index, high temperature foaming and high temperature deposits. SJ also introduced a 0.10 mass % limit on phosphorus content for improved catalyst compatibility.
SL 2001	Current	These oils were formulated to provide better high temperature deposit control and lower oil consumption.
SM 2004	Current	Designed to provide improved oxidation resistance, enhanced deposit protection, better wear protection, and improved low temperature performance over the life of the oil.
SN 2011	Current	Improved high temperature deposit protection for pistons, more stringent sludge control and seal compatibility. Better fuel economy, turbocharger protection and emission control system compatibility.

API intentionally omitted “SI” and “SK” from the sequence of categories since SI is reserved for Système International d’Unités and SK is the brand name of a South Korean oil company.

For automotive petrol engines, the latest engine oil service category includes the performance properties of earlier categories. If an owner’s manual calls for API SJ, SL or SM oil, API SN oil will provide complete protection.

It is expected that the next API standards for petrol engine oils will be available late 2017/early 2018. Some of these next generation oils will have lower multi-viscosity ratings such as 0W-16 (please refer to OilChat #3) to reduce friction for improved fuel economy. They will also include special additive packages to reduce engine wear. These oils are being developed for high output turbocharged gasoline (petrol) direct injection (GDI) engines. API has not yet confirmed the letter designation for the new oil classification, but it will likely be “SP” (skipping “SO”).

In the next issue of OilChat we will address the API classifications for diesel engine oils.

 

Always consult your vehicle owner’s manual to determine what motor oil you should use, and READ THE LABELS ON THE OIL YOU BUY.