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Discussion Starter #1
What’s written on your oil bottle and what does it mean.

This post may seem like going back to basics but I am constantly surprised by the amount of people who do not know or understand what is written on a bottle of oil and therefore no idea of what they are buying/using.

To be blunt about the subject, if a bottle of oil does not contain the following basic information then DO NOT buy it look for something that does!

1) The purpose for which it is intended (i.e. Motor oil, Gear oil etc)

2) The viscosity (i.e. 10w-40, 5w-30 etc for Motor oils and 80w-90, 75w-90 etc for Gear oils)

3) The specifications that it meets (should contain both API and ACEA ratings)

4) The OEM Approvals that it carries and the codes (i.e. MB229.3, VW503.00, BMW LL01 etc)

Ignore the marketing blurb on the label it is in many cases meaningless and I will explain later what statements you should treat this with some scepticism

So, what does the above information mean and why is it important?


All oils are intended for an application and in general are not interchangeable. You would not for example put an Automatic Transmission Oil or a Gear Oil in your engine! It is important to know what the oils intended purpose is.


Most oils on the shelves today are “Multigrades”, which simply means that the oil falls into 2 viscosity grades (i.e. 10w-40 etc)

Multigrades were first developed some 50 years ago to avoid the old routine of using a thinner oil in winter and a thicker oil in summer.

In a 10w-40 for example the 10w bit (W = winter, not weight or watt or anything else for that matter) simply means that the oil must have a certain maximum viscosity/flow at low temperature. The lower the “W” number the better the oils cold temperature/cold start performance.

The 40 in a 10w-40 simply means that the oil must fall within certain viscosity limits at 100 degC. This is a fixed limit and all oils that end in 40 must achieve these limits. Once again the lower the number the thinner the oil, a 30 oil is thinner than a 40 oil at 100 degC etc. Your handbook will specify whether a 30, 40 or 50 etc is required.


Specifications are important as these indicate the performance of the oil and whether they have met or passed the latest tests or whether the formulation is effectively obsolete or out of date.
There are two specifications that you should look for on any oil bottle and these are API (American Petroleum Institute) and ACEA (Association des Constructeurs Europeens d’Automobiles) all good oils should contain both of these and an understanding of what they mean is important.


This is the more basic as it is split (for passenger cars) into two catagories. S = Petrol and C = Diesel, most oils carry both petrol (S) and diesel (C) specifications.

The following table shows how up to date the specifications the oil are:


SG - Introduced 1989 has much more active dispersant to combat black sludge.

SH - Introduced 1993 has same engine tests as SG, but includes phosphorus limit 0.12%, together with control of foam, volatility and shear stability.

SJ - Introduced 1996 has the same engine tests as SG/SH, but phosphorus limit 0.10% together with variation on volatility limits

SL - Introduced 2001, all new engine tests reflective of modern engine designs meeting current emissions standards

SM - Introduced November 2004, improved oxidation resistance, deposit protection and wear protection, also better low temperature performance over the life of the oil compared to previous categories.


All specifications prior to SL are now obsolete and although suitable for some older vehicles are more than 10 years old and do not provide the same level of performance or protection as the more up to date SL and SM specifications.


CD - Introduced 1955, international standard for turbo diesel engine oils for many years, uses single cylinder test engine only

CE - Introduced 1984, improved control of oil consumption, oil thickening, piston deposits and wear, uses additional multi cylinder test engines

CF4 - Introduced 1990, further improvements in control of oil consumption and piston deposits, uses low emission test engine

CF - Introduced 1994, modernised version of CD, reverts to single cylinder low emission test engine. Intended for certain indirect injection engines

CF2 - Introduced 1994, defines effective control of cylinder deposits and ring face scuffing, intended for 2 stroke diesel engines

CG4 - Introduced 1994, development of CF4 giving improved control of piston deposits, wear, oxidation stability and soot entrainment. Uses low sulphur diesel fuel in engine tests

CH4 - Introduced 1998, development of CG4, giving further improvements in control of soot related wear and piston deposits, uses more comprehensive engine test program to include low and high sulphur fuels

CI4 Introduced 2002, developed to meet 2004 emission standards, may be used where EGR ( exhaust gas recirculation ) systems are fitted and with fuel containing up to 0.5 % sulphur. May be used where API CD, CE, CF4, CG4 and CH4 oils are specified.


All specifications prior to CH4 are now obsolete and although suitable for some older vehicles are more than 10 years old and do not provide the same level of performance or protection as the more up to date CH4 & CI4 specifications.

If you want a better more up to date oil specification then look for SL, SM, CH4, CI4


This is the European equivalent of API (US) and is more specific in what the performance of the oil actually is. A = Petrol, B = Diesel and C = Catalyst compatible or low SAPS (Sulphated Ash, Phosphorus and Sulphur).

Unlike API the ACEA specs are split into performance/application catagories as follows:

A1 Fuel economy petrol
A2 Standard performance level (now obsolete)
A3 High performance and/or extended drain
A4 Reserved for future use in certain direct injection engines
A5 Combines A1 fuel economy with A3 performance

B1 Fuel economy diesel
B2 Standard performance level (now obsolete)
B3 High performance and/or extended drain
B4 For direct injection car diesel engines
B5 Combines B1 fuel economy with B3/B4 performance

C1-04 Petrol and Light duty Diesel engines, based on A5/B5-04 low SAPS, two way catalyst compatible.
C2-04 Petrol and light duty Diesel engines, based on A5/B5-04 mid SAPS, two way catalyst compatible.
C3-04 Petrol and light duty Diesel engines, based on A5/B5-04 mid SAPS, two way catalyst compatible, Higher performance levels due to higher HTHS.

Note: SAPS = Sulphated Ash, Phosphorous and Sulphur.

Put simply, A3/B3, A5/B5 and C3 oils are the better quality, stay in grade performance oils.


Many oils mention various OEM’s on the bottle, the most common in the UK being VW, MB or BMW but do not be misled into thinking that you are buying a top oil because of this.

Oil Companies send their oils to OEM’s for approval however some older specs are easily achieved and can be done so with the cheapest of mineral oils. Newer specifications are always more up to date and better quality/performance than the older ones.

Some of the older OEM specifications are listed here and depending on the performance level of your car are best ignored if you are looking for a quality high performance oil:

VW – 500.00, 501.00 and 505.00

Later specs like 503, 504, 506 and 507 are better performing more up to date oils

MB – 229.1

Later specs like 229.3 and 229.5 are better performing more up to date oils.

BMW – LL98

Later specs like LL01 and LL04 are better performing more up to date oils.


Above is the most accurate guidance I can give without going into too much depth however there is one final piece of advice regarding the labelling.

Certain statements are made that are meaningless and just marketing blurb, here are a few to avoid!

Recommended for use where……………
May be used where the following specifications apply……………
Approved by………………………..(but with no qualification)
Recommended/Approved by (some famous person, these endorsements are paid for)
Racing/Track formula (but with no supporting evidence)

Also be wary of statements like “synthetic blend” if you are looking for a fully synthetic oil as this will merely be a semi-synthetic.

Like everything in life, you get what you pay for and the cheaper the oil the cheaper the ingredients and lower the performance levels.


15,637 Posts
Hello Simon...the oil i am using is shell helix ultra fully synthetic has the number api sl/cf acea a3/b4-98...what does this mean please, is it ok for my car (156 1.8 ts)

cheers like :)

0 Posts
That's a citrus oil you fool, your engine will blow up (it'll smell nice and keep the cats away though) :D

15,637 Posts
VO2Max said:
That's a citrus oil you fool, your engine will blow up (it'll smell nice and keep the cats away though) :D

you can replace a blown engine, but you cant get rid of the smell of cats **** for ages :lol: :lol: :lol:

1,111 Posts
Discussion Starter #7 said:
Hello Simon...the oil i am using is shell helix ultra fully synthetic has the number api sl/cf acea a3/b4-98...what does this mean please, is it ok for my car (156 1.8 ts)

cheers like :)
It should be fine but unless your oil temps are very high a 10w-40 or 5w-40 would be more suitable.


524 Posts
Didn;t know we were studying open university on this forum.
About to change my oil and filter thanks for pointing a few things out oilman.

1,111 Posts
Discussion Starter #10
Not quite open university but basic stuff really.

This is more open university for those that are interested!


We are asked all the time about the use of magic addatives / miracle cures.

This one is certainly no exception in its claims.

Having read about it, I asked Silkolene was this a miracle addative and were the claims possible or more importantly technically possible?

If you're interested in the stuff, please read on as it's an eye-opener!

Quote: John Rowland (Silkolene's Chemist)

The mode of action of the ‘NanoLub’ particles is based upon a fallacy, i.e., that very small spheres can reduce friction and carry high loads by rolling between two moving surfaces, by analogy with ball bearings. (Their ‘Technical Note’ states: ‘NanoLub………….is extremely strong and rolls along surfaces to provide excellent lubrication.’ In fact, this simply does not happen due to effects that are not important at ‘macro’ scale, but significant at ‘micro’, and very important at ‘nano’ scales.

If an average size ball made of hard material rests on (for example) a toughened steel surface, it will make a small indentation. (Nothing is perfectly rigid, not even diamond.) If a force is applied to the ball, the depth of the indentation will increase, but so will its area; with a large ball, the area will be large relative to the depth. Provided that the elastic limit of the steel (Young’s Modulus) is not exceeded, the indentation will be restored to its original size when the force is removed. Thanks to this effect, precision ball and roller bearings have been successfully used for about 120 years. However, if a I micron (1000 nano-metres) diameter sphere is pressed into contact with a steel surface, the maximum possible area of the indentation will of course be equal to the maximum cross-sectional area of a 1 micron sphere, which is 7.9 x 10 to -13 square metres! In other words, a very light pressure will easily exceed the elastic limit of the steel and embed the sphere in its surface. Even 1mm hard steel balls, only used in very lightly-loaded ball bearings, have a cross-sectional area 1 million times greater. (The NanoLub particles are said to be 80 – 220 nanometres, or 0.08 to 0.22 microns in diameter.)

The embedding of hard particles into bearing surfaces is well known to bearing manufacturers, and its effects have been well understood for many years: by initiating micro-cracks and grain boundary dislocations, the fatigue life of rolling-element bearing surfaces is severely curtailed. All manufacturers insist that long bearing life depends upon clean oil or grease. There have been numerous studies published showing that particulates reduce bearing life, so NanoLub must not be used in any application where this type of bearing is used. (Similar effects occur between gear teeth.)

High-speed plain bearings as used in all present-day automotive engines depend upon ‘hydrodynamic’ lubrication, which depends upon thick (100 micron or more) fluid films generated by motion and viscosity. (This was researched by the Victorian engineer Beauchamp Tower in the late 19th Century). So particles smaller than 1 micron will have little opportunity to act as a lubricant in a much thicker oil film. Even so, embedding can occur at start-up/shutdown where ‘boundary’ thin film lubrication is dominant, leading to bearing damage. As with rolling bearings, hard particles in the oil are not a good idea, hence the use of oil and air filters on all engines made since about 1950.

The makers of NanoLub correctly point out that: ‘Common solid lubricants are layered compounds like graphite, molybdenum disulphide and tungsten disulphide. The layers slide past each other to reduce friction.’ Unfortunately, they seem to have failed to understand that layered solid lubricants act as lubricants only because they are layered. One sheet of graphitic carbon atoms for example is not a lubricant; two are! If a layered solid lubricant is treated in such a way so that its layers cannot move relative to each other, it cannot act as a lubricant, so the ‘nested sphere’ structure of NanoLub actually prevents it from acting as a lubricant.

In practice, I strongly suspect that the ‘nano-spheres’ actually disintegrate under high pressure, so the WS2 can act as a layered solid lubricant. (All rather ironic that NanoMaterials Inc. have gone to great lengths to stop WS2 working, and the only occasion when it has some effect is when the nano-particles break down!) Although they draw comparisons with the C60 buckminsterfullerene spherical ‘nano-particle’, this is a much smaller (0.7nano-metre) sphere which is a true molecule and consequently very resistant to fracture.

The ‘NanoLub Technical Note’ includes some wear test data, without stating the type of apparatus used. It is well known that some primitive wear testers such as the ‘Falex’ and ‘4-Ball’ generate unrealistically high pressures which do not replicate ’real-world’ conditions. (In the 1980s Shell published a table of wear test results ‘proving’ that milk and beer were superior lubricants to SAE 90 gear oil according to some types of wear test. I can send a copy I you wish.) The NanoLub tests are not very rigourous, using unspecified ‘Gear Oil 85W/140’ with and without the additive. A correct and believable procedure would involve using a mineral base oil with various levels of NanoLub, dispersed ‘conventional’ WS2, and a sulphur/phosphorus EP compound such as Anglemol 99. I confidently predict that properly controlled wear and friction tests using reputable apparatus such as the FZG Gear procedure would show NanoLub to be no more effective than conventional particle-free additives which act chemically or electrostatically, thus having no adverse effect on bearing life.

As a general comment, I find it difficult to believe that the founders of ‘ NanoMaterials Inc’ could be so ignorant of the vast amount of research and practical experience that has gone into lubrication problems over the past 200 years. Tomas Young, who researched the elasticity of materials around 1810, would have clearly understood the fallacy of very small ball bearings, for example. Any first-year Engineering student could have pointed out the pitfalls.

In common with many ‘magic additive’ advocates, there is also the curious belief that dry-lubricated bearings can operate at low friction. In fact, any reputable engineer avoids oil or grease-free bearings like the plague, because regardless of the coating used the friction is always ten times worse than an oil-lubricated situation, and over 100 times worse than a pressure-fed hydrodynamic bearing!

Even so, they’ve got a unit on the ‘Weizmann Science Park’ and a (virtual?) office in New York, so presumably somebody believes in them! But of course, looking on the Internet I see that they have the support of Wall Street, where fools are soon parted from their money.


I rest my case on magic addatives!

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