Why engine oils are not all created equal

By November 23, 2019 November 25th, 2019 Latest news

If there are considerable benefits to using a premium-grade engine oil why don’t more motorists pay attention to what’s on the label?

According to Piero Prinzi, senior technical officer/trainer at the Kangan Institute’s Automotive Centre of Excellence, it’s because many are unaware that not all engine oils are created equal.

The teacher, technician, racing driver and auto enthusiast says he wishes more Australian vehicle owners were educated about the risks and benefits associated with engine oil selection.

“On the one hand, premium-grade oils can bring significant benefits in terms of longevity, fuel economy, performance and reduced emissions,” Mr Prinzi says. “On the other hand, lesser-grade oils that do not meet the vehicle manufacturer’s specification have the potential to result in costly engine repairs and risk voiding the warranty.

“Low-quality oils are also hazardous to the environment as they do not meet the industry standards set by governing bodies such as the ACEA and API, which are responsible for drawing up regulations on CO2 emissions.”

Mr Prinzi, who grew up in Italy, home of the famous Agip brand of premium lubricants, says a compatible top-quality oil allows the vehicle to operate at ultimate efficiency and performance, which can equate to lower fuel costs, more power and reduced emissions.

As well as lecturing at Australia’s leading automotive college, Mr Prinzi is a self-confessed car and motorbike enthusiastic who uses Eni lubricants in his own vehicles. His collection includes a Ducati SS1000DS, Alfa Romeo Mito, Toyota Hiace (full import), two Honda Jazz, Moto Guzzi Stelvio NTX, Piaggio Beverly 350 ST and a Piaggio X8 250-i.

Needless to say he was delighted when Agip lubricants became available in Australia last year through Chematek under the internationally recognised Eni label.

“Growing up with Agip, from being that little kid in my father’s garage, to studying mechanics, technology and chemistry, has made me understand quality, efficiency and compatibility, as well as the differences between oil grades and oil types,” Mr Prinzi says.

“Although premium oils may cost a little more, they will save money in the long run because a vehicle that is well cared for will need fewer repairs. Using low-quality or cheap oil can even cost dearly, should an engine or transmission need to be replaced.

“There are also big benefits in terms of durability. Moving parts will wear over time at varying rates. To enable the lowest amount of degradation and extend the life of the parts, using a quality oil is the way to go. It can make a big difference on critical components such as the engine, transmission and final-drive.”

Quality oils are also formulated to provide great fuel efficiency as they both protect and lubricate the engine.

“A good-quality compatible oil does not need to be expensive, but it does need to meet the given industry standards,” Mr Prinzi says.

So what should we be looking for on the label when choosing or specifying an engine oil? How do we judge its compatibility?

“The first thing to do is consult the owner’s manual for your vehicle as this will list the recommended oil weight, whether that’s a standard, such as 10W-30 or something more unusual,” Mr Prinzi says.

API’s latest service standard is SN 1 (SP to be introduced next year), which refers to a group of laboratory and engine tests, including the latest series for control of high-temperature deposits. The API donut on the label tells you if the oil meets the current SN 1 service rating (C for diesel engines). It also provides the Society of Automotive Engineers (SAE) viscosity number and tells you if the oil has passed the test listed for SN 1 service.

Next to look at is the viscosity (thickness) that’s suitable for the temperatures the vehicle normally operates in. Again, the owner’s manual will provide information on this.

“Viscosity refers to a fluid’s resistance to flow,” Mr Prinzi says. “With the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold and another when hot. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.

“It’s also important to note that lubricants do have a life span, which can be affected by factors such as usage, location and conditions.”

Here’s a quick run-down of the main types of motor oil available:

Premium Conventional Oil: This is the standard new-car oil and all leading brands have one for service level SN, available in several viscosities. Even more important though is changing the oil and filter regularly. Twice a year or every 10,000kms is good practice.

Full Synthetic Oil: Made for high-tech engines, these oils pass stringent tests that mean they have superior longer-lasting performance in all critical areas, from viscosity index to protection against deposits. They flow better at low temperature and maintain peak lubricity at high temperatures. These oils are expensive and not every engine needs them. In fact there may be some features needed that full synthetic oils can’t provide.

Synthetic Oil Blend: Featuring a dose of synthetic oil mixed with organic oil, these oils are formulated to provide protection for somewhat heavier loads and high temperatures. This generally means they are less volatile, so they evaporate far less, reducing oil loss and increasing fuel economy.

High-Mileage Oil: Today’s vehicles last longer, running the mileage well into six figures. Crankshaft seals may have hardened and lost their flexibility, causing them to leak, especially at low temperatures, and potentially crack. The higher-mileage oils are formulated with seal conditioners that flow into the pores of the seals to restore their shape and flexibility.