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Discussion Starter #1
This post may seem like going back to basics but we are constantly surprised by the amount of people who do not know or understand what is written on a bottle of oil and therefore have no idea of what they are looking for, buying or using.

This post should help as a basic guide, for more detailed information contact us and we will be happy to help.

So, 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, VW504.00, FORD 913a/b, BMW LL04 etc)

Ignore the marketing blurb on the label it is in many cases meaningless and we will explain later what statements you should treat with skepticism.

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

THE BASICS

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.

VISCOSITY

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 thin oil in winter and a thicker oil in the 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. I.E. 5w is better than 10w etc

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

Specifications are important as these indicate the performance of an oil and whether it has 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.

API

This is the more basic of the two specs 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:

PETROL

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.

Note:

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.

DIESEL

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.

Note:
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

ACEA

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.

APPROVALS

Many oils mention various Car Manufacturers on the bottle, the most common in the UK being VW, MB, BMW, Ford or Vauxhall but do not be misled into thinking that you are buying top quality 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.


FINALLY

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

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

Recommended for use where……………

May be used where the following specifications apply……………

Approved by………………………..(but with no qualification or specification)

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. The cheaper the oil the cheaper the
ingredients, lower the performance levels and older the specs it meets so beware!

If you would like further advice then please feel free to ask here or contact us via our website or email.

Simon & Guy
Opie Oils
 

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Discussion Starter #2
Oil – You get what you pay for!

Costs of synthetics vary considerably. The most expensive are the “Ester” types originally only used in jet engines. These cost 6 to 10 times more than high quality mineral oils.

The cheapest synthetics are not really synthetic at all, they are dug out of the ground and not manmade. These are in fact specially refined light viscosity mineral oils known as “hydrocracked” oils.

“Hydrocracked” oils have some advantages over their equivalent mineral oils, particularly in lower viscosity motor oils such as 5w-30 and 5w-40 and they cost about 1.5 times more than good quality mineral fractions. This is the “synthetic” which is always used in cheap oils that are labelled “synthetic”.

So, why are these special mineral oils called “synthetic”?

Well, it all came about from a legal battle that took place in the USA more than ten years ago. Sound reasons (including evidence from a Nobel Prize winning chemist) were disregarded and the final ruling was that certain mineral bases that had undergone extra chemical treatments could be called “synthetic”.

Needless to say, the marketing executives wet their knickers with pure delight! They realised that this meant, and still does, that the critical buzz-word “synthetic” could be printed on a can of cheap oil provided that the contents included some “hydrocracked” mineral oil, at a cost of quite literally a few pence.

So, the chemistry of “synthetics” is complex and so is the politics. The economics are very simple though.

If you like the look of a smart well-marketed can with “synthetic” printed on it, fair enough, it will not cost you a lot; and now you know why this is the case, it’s really only a highly processed mineral oil.

But, if you drive a high performance or modified car, and you intend to keep it for several years, and maybe do the odd “track day” or “1/4 mile”, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil.

These oils cost more money to buy, because they cost a lot more money to make.

Very simply, you always get what you pay for, cheap oils contain cheap ingredients, what did you expect!
 

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Rather than basing my choice on brand or price, I ensure that the correct viscosity and quality grading is adhered to, then shop around for the best deal.

The cheapest oil is the recycled stuff collected from garages carrying out oil changes, filtered and given some additives - its better than nothing - but not by very much.

Interesting post.

Paul:)
 

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Costs of synthetics vary considerably. The most expensive are the “Ester” types originally only used in jet engines. These cost 6 to 10 times more than high quality mineral oils.

The cheapest synthetics are not really synthetic at all, they are dug out of the ground and not manmade. These are in fact specially refined light viscosity mineral oils known as “hydrocracked” oils.

“Hydrocracked” oils have some advantages over their equivalent mineral oils, particularly in lower viscosity motor oils such as 5w-30 and 5w-40 and they cost about 1.5 times more than good quality mineral fractions. This is the “synthetic” which is always used in cheap oils that are labelled “synthetic”.

So, why are these special mineral oils called “synthetic”?

Well, it all came about from a legal battle that took place in the USA more than ten years ago. Sound reasons (including evidence from a Nobel Prize winning chemist) were disregarded and the final ruling was that certain mineral bases that had undergone extra chemical treatments could be called “synthetic”.

Needless to say, the marketing executives wet their knickers with pure delight! They realised that this meant, and still does, that the critical buzz-word “synthetic” could be printed on a can of cheap oil provided that the contents included some “hydrocracked” mineral oil, at a cost of quite literally a few pence.

So, the chemistry of “synthetics” is complex and so is the politics. The economics are very simple though.

If you like the look of a smart well-marketed can with “synthetic” printed on it, fair enough, it will not cost you a lot; and now you know why this is the case, it’s really only a highly processed mineral oil.

But, if you drive a high performance or modified car, and you intend to keep it for several years, and maybe do the odd “track day” or “1/4 mile”, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil.

These oils cost more money to buy, because they cost a lot more money to make.

Very simply, you always get what you pay for, cheap oils contain cheap ingredients, what did you expect!

yes spot on but on the other hand a lot of the cost of oil's is the label on the container, dont you think this can be the case sometimes, you paying £20 for the oil and another £20 for the brand label?
 

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Discussion Starter #5
Are 5w and 0w oils too thin?

I read on many forums about 0w and 5w oils being too thin.

0w-40, 5w-40, 10w-40 and 15w-40 are all the same thickness (14 centistokes) at 100degC.

Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid.

As viscosity varies with temperature, the value is meaningless unless accompanied by the temperature at which it is measured. In the case of oils, viscosity is generally reported in centistokes (cst) and usually measured at 40degC and 100degC.

So, all oils that end in 40 (sae 40) are around 14cst thickness at 100degC.

This applies to all oils that end in the same number, all oils that end in 50 (sae 50) are around 18.5cst at 100degC and all oils that end in 60 (sae 60) are around 24cst at 100degC.

With me so far?

Great!

Now, ALL oils are thicker when cold. Confused? It's true and here is a table to illustrate this.

SAE 40 (straight 40)

Temp degC.........................Viscosity (thickness)

0..........................................2579cst
20..........................................473cst
40..........................................135cst
60..........................................52.2cs t
100........................................ 14cst
120.........................................8.8cst

As you will see, there is plenty of viscosity at 0degC, in fact many times more than at 100degC and this is the problem especially in cold weather, can the oil flow quick enough to protect vital engine parts at start up. Not really!

So, given that an sae 40 is 14cst at 100degC which is adequate viscosity to protect the engine, and much thicker when cold, how can a 0w oil be too thin?

Well, it can't is the truth.

The clever part (thanks to synthetics) is that thin base oils can be used so that start up viscosity (on say a 5w-40 at 0degC) is reduced to around 800cst and this obviously gives much better flow than a monograde sae 40 (2579cst as quoted above).

So, how does this happen, well as explained at the beginning, it's all about temperature, yes a thin base oil is still thicker when cold than at 100degC but the clever stuff (due to synthetics again) is that the chemists are able to build these oils out of molecules that do not thin to less than 14cst at 100degC!

What are the parameters for our recommendations?
Well, we always talk about good cold start protection, by this we mean flow so a 5w will flow better than a 10w and so on. This is why we recommend 5w or 10w as the thickest you want to use except in exceptional circumstances. Flow is critical to protect the engine from wear!

We also talk about oil temps, mods and what the car is used for. This is related to the second number xw-(XX) as there may be issues with oil temperatures causing the oil to be too thin and therefore the possibility of metal to metal contact.

This is difficult to explain but, if for example your oil temp does not exceed 120degC at any time then a good "shear stable" sae 40 is perfectly capable of giving protection.

"Shear stability" is important here because if the oil shears it thins and that's not good!

However, if you are seeing temperatures in excess of 120degC due to mods and track use etc then there is a strong argument to using an sae 50 as it will have more viscosity at these excessive temperatures.

There are trade offs here. Thicker oils cause more friction and therefore more heat and they waste power and affect fuel consumption so it's always best to use the thinnest oil (i.e. second number) that you can get away with and still maintain oil pressure.

I hope this helps explain a bit.

Cheers

Guy.
 

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Very interesting, I might change my choice of oil now, obviously the oil companies don't give out this type of information as 99% of motorists wouldn't read it and if they did wouldn't understand it.

I have always been frightened of using what I thought was a thin oil like 5/40 thinking the 5 might not lubricate properly.

My motoring started when I used castrol XL or XXL or even D ! The Castrol D smelt great.
 

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How many Litres of oil is needed for a 1999 Renault Clio II 1.2 8v?
I changed my oil today and want to make sure I put the correct amount in.
I used the dipstick to measure, putting roughly 3.5 ltres in.
 
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How many Litres of oil is needed for a 1999 Renault Clio II 1.2 8v?
I changed my oil today and want to make sure I put the correct amount in.
I used the dipstick to measure, putting roughly 3.5 ltres in.[/QUOTEWiyh all respect I would suggest to you and all other DIYers that a Haynes manual, puchased or borrowed, will give all info needed and pay for itself very quickly in money saved by self servicing your motor.
PS. dipstick is a good indicator of oil capacity, that's why its there!!
 

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On the Saab forum where i moderate a lot of US owners use a diesel designed oil in petrol engines because of the higher cleaning properties of diesel oils. Is there an advantage to this or could they be doing damage to their engines despite using the same weight oil?
 

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Can I get some help with oil for my modus, please? I have a 2011 1.6 and keep seeing different advice for the oil - either 5w30 or 5w40. I'm also not sure how to top up - what looks like the oil filler cap is almost unreachable under some cowling. SOS!
 
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