Engine oil is often referred to as the “lifeblood” of your car. It flows through the heart of your vehicle (the engine) enabling all the different components to work in harmony. When interviewing Govert Spit (Global Head of Lubricants, Puma Energy) for some brochures I was writing, I discovered something startling. This fact applied to all mechanical entities across many different spectrums, from sugar cane and shipping all the way through to the cement and high street industries. According to MIT, 6% of the gross national product in the US is spent on repairing mechanical wear damage. But it’s not just the costs of the repairs – businesses will need to foot the bill for any overtime accrued during the repair process, and of course any downtime caused by mechanical failure will result in reduced revenues. Ultimately, 60% – 70% of all mechanical issues relate to lubrication in some way!
Whilst the above comment relates to vastly larger entities than your car, the principle remains. The obvious intersection of this knowledge and the car owner lies in the choices made around which engine oil to put into their car. The purpose of this newsletter is to demystify some of the numbers and letters seen on the oil packaging. However, one golden rule remains: ALWAYS use what is specified by the manufacturer! That way, you can be certain that decades of research and design which have produced the perfect choices for your car are behind your decision-making… I am consistently amazed at how many are willing to risk serious damage by adding unauthorised products for no discernible reason!
Different oils have different functions and properties, and there are many different oils utilised in a vehicle, such as engine, gear, diff, hydraulic oil etc. It is very important not to confuse all the different oils. Some engine oils may even have more than one performance level (e.g. they can also be used as hydraulic fluid), so you can start to understand just how dangerous it is to used incorrect lubricants. There are engine oils currently on the shelves at auto parts stores, petrol station convenience stores, food stores, and other retail outlets that can cause immense harm to your car’s engine. This is particularly true in Africa. One can even see oils sold on the side of the road in the more remote areas of Africa – purchase and use at your engine’s peril.
The Benefits of the Correct Oil
In a nutshell the proper choice of engine oil allows for easy starts (even when it’s really cold), whilst also enabling the best fuel consumption possible (more important than ever with the current fuel prices). On a day-to-day basis, the correct engine oil allows the engine to run cleaner, providing better protection, performance and, ultimately, a longer engine life as wear and tear are reduced. This can decrease maintenance required. Incorrect choices can lead to difficult cold starts, oil leaks, the smell of burning oil (inadequately lubricated engine parts cause friction, which can burn the oil), poor fuel economy, and engine ticking in cold weather. These are all signs that the wrong engine oil is being used, and is not properly lubricating the moving parts, leading to metal-on-metal contact, friction, heat and ultimately serious damage. Far more costly than simply purchasing the correct product in the beginning! So, let’s get to the meaning of the symbols…
The American Petroleum Institute
A confusing array of oils exist on the market, and even more additives – some which can actually damage your vehicle. The American Petroleum Institute (API) is an organisation which assigns a rating to every blend of motor oil that meets the International Lubricant Standardization and Approval Committee’s (ILSAC) standards (this committee is run by U.S. and Japanese automobile manufacturers). When an oil has been given the seal of approval with an API rating, it means that the oil meets a minimum performance standard set by these auto manufacturers.
There are a couple of formats which important to understand. The first would contain two letters starting with an “S” – this indicates that the oil is for gasoline (petrol) engines. Why would there be variations, and why can’t there only be one set of letters to show whether for petrol or diesel engines? Because API ratings change every now and then. There’s an incredibly long list of API ratings, each created for a specific time period of car manufacture. Let’s keep it simple, and only talk about the current one. The letters “SO” were omitted from the sequence of letter designations for API Service Categories, due to a common association with other organizations or systems e.g. “SO” because it’s an acronym for Standard Oil, which is still sold in Canada. Two letters, usually starting with a “C”, followed with a “-4” indicates that the oil is for diesel engines.
The two new ILSAC specifications (GF-6A and GF-6B) represent the latest performance requirements for gasoline engine oils as set by the International Lubricant Specification Advisory Committee (ILSAC), and API Service. “SP” is the newest API gasoline engine oil standard, released in May 2020. It is designed to provide protection against low-speed pre-ignition, timing chain wear protection, improved high temperature deposit protection for pistons and turbochargers, and more stringent sludge and varnish control. CK-4 oil is the newest generation of diesel engine oil. CK-4 oils maintain traditional high temperature/high shear (HTHS) viscosity and FA-4 oils are lower HTHS viscosity. Of the two oils, FA-4 oils focus on enhanced fuel efficiency for newer engines. Both CK-4 and FA-4 oils help reduce carbon dioxide and greenhouse gas emissions and also maintain engine durability while improving oxidation resistance, shear stability and aeration control.
As a general rule of thumb, you can use newer oils in older engines, but NOT vice versa. The industry calls this “backwards-compatible.”
Original Equipment Manufacturer (OEM)
An OEM approved oil is one that has been developed with the original equipment manufacturer, using a blend of base oils and additives that suit the engine’s requirements – and is then extensively tested to ensure full compliance. These manufacturers and the associated specification adherence usually appear on the packaging of such oils.
SAE Viscosity Grade
Years ago, in countries with more extreme climates, drivers would use a winter grade oil during cold weather, since it was designed to be thin and flow more easily in low temperatures. In the summer, they would swap out their winter oil for a thicker one, since hot temperatures thin out oil. Today, multi-grade oils have viscosity modifiers, allowing them to be used year-round. Viscosity is the property of a liquid that describes how fast or slowly it will flow. A liquid with high viscosity – that is thick, like peanut butter – will flow slowly. Technically, viscosity is the ‘resistance to flow’ of a fluid or the internal friction of a fluid in motion. The Society of Automotive Engineers (SAE) define a numerical system for grading motor oils according to viscosity.
Let’s use a practical example – e.g. “5W-30”. So, for example, “5W-30” oil, the ‘W’ stands for winter, and so the 5W part is describing the viscosity (i.e. 5) of the oil at low temperatures. The lower the number, the lower the viscosity of the oil and the faster the oil will move around the engine at vehicle start up.
The high temperature (i.e. 30) viscosity is the number after the dash and is related to the viscosity of the oil as it is moving around your engine after the car has warmed up and is at normal engine temperature. The higher the number, the higher the viscosity of the oil – which allows the oil to circulate at an appropriate consistency.
Your owner’s manual will specify the viscosity grade required for your car’s engine.
Synthetic vs Conventional Base Oils
There have been many debates on the subject of synthetic vs conventional base oils. Petroleum (or conventional) base oils are obtained by refining from crude oil. Contaminating elements (e.g. sulphur, nitrogen, oxygen and metal components such as nickel or vanadium) are inherent to crude oil and cannot be completely removed through the refining process. The oil refining process separates the various types of molecules in the oil by weight, leaving molecules similar in weight but dissimilar in structure, reducing performance. They can be less chemically stable, oxidizing and acidifying more easily, and generally quicker to break down and lose their protective qualities.
At the opposite end of the spectrum, we have synthetic base oils, which are highly engineered to include only beneficial molecules. No contaminants or molecules that don’t serve a designed purpose. Their pure, uniform molecular structures and versatility impart properties that provide better friction-reduction, optimum fuel efficiency, maximum film strength and extreme-temperature performance that conventional lubricants just can’t touch.
This is an incredibly vast subject, with far too much to cover than is afforded by this short newsletter. I do hope that this article has at least piqued your interest, and I encourage you to go and do more research if the subject interests you. The most important takeaway from this read? Comply 100 percent with the manufacturer’s specifications, and you will be doing both your car and your pocket a huge favour…
With grateful thanks to those who took the time to do an interview with me for this column – you know who you are ?.
Jacqui Ikin & The Cross Country Team