Oil labelling explained

[oilman]

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?

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 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

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of the oil and whether they have met or passed the latest tests or whether the formulation is effectively obsolete or out of date.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.

API

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:

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 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.


FINALLY

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.

If you want further advice then please feel free to ask here or contact us through our website at www.opieoils.co.uk.

Cheers
Simon

[moleman]

Originally Posted by oilman

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.

I have always wondered about that.

What an excellent post.

Thank you Simon.

[Demon Dave]

excellent read. Very informative.

Without a doubt one of the best posts on here in recent weeks.

Top marks.

Thanks for sharing.

Dave

[ISJ]

Yep i knew roughly the 10w40 thing but i had forgotten exactly what everything means, i guess working day in day out with oils and such you have to know this information.

Thanks for sharing, it'll certainly help people out in the future!

[tim b]

Nice bit of info, cheers.

Originally Posted by oilman

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.

Never quite got this though. So the lower the number, the thinner. So a 10 is thinner than a 40?

If that's the case, and its 10 when cold, (winter), then the oil is thinner when cold, and gets thicker when hot, (up to a 40)? That's pretty impressive surely, if when you get this oil cold it thins out to help starting, but when warmed up it gets thicker to protect the engine.

I'm sure hot oil is thinner, for example its much easier to drain oil out of the sump if the engine's been running and everything is nice and warm, but from the above info it should be thicker.

Can someone clarify that for me?

[iceager]

Tim.

The numbers 10w and 40 as in ( 10w-40) cant be compared, they are two diffrent index's.

10w means how thin the oil is at cold engine, before start.
the 40 is another index for how thin the oil is at 100 degrees.
its almost like the diffrence in HP at wheels and fly, you can't compare them as they are not indicating the same.

the oil have 2 ability's. 1# cold and 2# warm. If you take a frying pan and put some cooking oil on when cold you see the "10w" its not ultra thin but it is thin.
heat up the pan and you see the oil starts to spread out and becomes thin and at 100 degrees it has to have a specific viscosity ( the 40 ) if heated too much the oil will run away from the hottest area on the pan and it is no longer usefull anymore ( that would be an oil that is cheap and lack information on the label. eg a poor oil)

Corect me if im wrong here Oilman

[oilman]

Indeed, they are not comparable.

The w number is measured at ferrous monkey endangering temperatures, for example 10w at -30degC.

The second number is the minimum to which the oil must thin at 100degC, in the case of a 40, it's 14cst.

The measurements are not related as they indicate cold crank performance and viscosity at 100degC

Cheers
Simon

[tim b]

Ah right, so different viscosity measurements/ranges then.

So its not, (for example), 10 centistokes when cold and 40 centistokes when hot?

Instead its, (again for example), 10 wibblybongs when cold and 40 dingdang doobly-blops when hot, (different units of measure)?

[oilman]

No, I don't know of a fluid that thickens with temperature.

More like 3000cst at -30, 500cst at 0degC and 14cst at 100degC (a 5w-40 that is).

Cheers
Simon

[Durzel]

Gonna move this to the Maintenance section so I can sticky it

[oilman]

No problems.

Cheers
Simon

[R32 Combat]

IIRC, Nissan recommend 7.5w-30 fro the R32 GTR. Yet no-one in the UK seems to use it.

Can you explain?

Also, if you have a higher than normal capacity oil pump, and the pump runs at a higher pressure, (e.g. a HKS,JUN etc oil pump) does this effect the choice of oil?

Cheers

Andy

[oilman]

Indeed, according to my database dependent on ambient temps, Nissan recommend 5w-30 or 5w-40 for a stock car used on the road.

5w-40 is more suited to the UK ambient climate so that's the stock recommendation.

The reasons why people tend to use 10w-50, 15w-50 is because many cars are not stock and used off road as well which puts more stress and heat into the oil calling for a higher film strength (thickness) and more high temperature protection.

Let's call it headroom when the engine is stressed.

Why people use sae 60 oils I will never know but then again we have covered this before.

We recommend 5w-40 for stock road cars and 10w-50/15w-50 for track cars and modded cars oh and for those that love the loud pedal.

Cheers
Simon

Originally Posted by R32 Combat

IIRC, Nissan recommend 7.5w-30 fro the R32 GTR. Yet no-one in the UK seems to use it.

Can you explain?

Also, if you have a higher than normal capacity oil pump, and the pump runs at a higher pressure, (e.g. a HKS,JUN etc oil pump) does this effect the choice of oil?

Cheers

Andy

[R32 Combat]

Thanks Simon.

[NicoORT]

The seller of my car use 10W60 it's good or not for my GTR?