As fuel prices rise, drivers are paying close attention to how much fuel their vehicles are consuming. It is common to talk about driving habits or vehicle maintenance, but many do not consider the quality of the engine oil.
The type of oil (lubricant) used can actually influence how much fuel is consumed. But how? And does “better” oil always mean lower consumption? Let’s investigate.
Engine Oil Base and Its Effect on Fuel Economy
There are three distinct base expressions of engine oils: mineral, semi-synthetic, and synthetic. Each one has different properties and different base formulations, affecting engine performance.
Mineral oils are the most chemically basic and therefore cheapest oils available. Mineral oils are derived from crude oil by refining and protecting it. Additional measures involve just physical separation, not complex chemical treatment.
Mineral oils lack long chain hydrocarbons, having the least performance or lubricating properties–thus producing the most internal friction, the greatest higher input of fuel consumption. For this reason, they are not. The mineral oil is most often used in older vehicles, some agricultural equipment, and vintage engines.
On the other end of the spectrum are synthetic oils. Synthetic oils are chemically synthesized oils having the best quality and best stability under the widest operating parameters. Synthetic oils will reduce friction between engine components and reduce fuel consumption while increasing efficiency. These oils are mostly suggested in high-performance modern engines.
Semi-synthetic oils are the middle-ground base oil choice. Semi-synthetic oils include a combination of mineral base oils and synthetic additives. Some features are improved vs. mineral oils, and they cost less than full synthetics. Semi-synthetic oils are generally an appropriate best choice, particularly for owners of mid-value vehicles.
The Importance of Oil Viscosity on Fuel Consumption
Viscosity is really the oil’s flowability within the engine. The better the flowability (the lower the viscosity), the faster the lubricant reaches the engine components, and the less internal friction. This can help fuel consumption, especially during frequent engine start-ups in urban driving situations.
Oils with a viscosity of 0W-20 or 5W-20 are examples of lower viscosity oils, and often promote better fuel economy for that reason. Care should be taken to ensure the viscosity requested by the vehicle manufacturer is followed; oils that are too thin may not provide adequate pressure or protection for the engine’s components, especially at higher temperatures.
Special Labels Found on Oil Packaging
Manufacturers of engine oil are stepping up their labelling efforts regarding the fuel-saving properties of the oil on the packaging. This helps consumers select lubricants that help their engines operate efficiently.
A common label is “FE” (Fuel economy), which is used on oil produced using both European and American standards. This label indicates oil designed to reduce internal engine friction, which leads directly to lower fuel consumption. The similar “ECO” label is typically used only as a marketing term designed for product use with modern engines with exhaust aftertreatment systems.
The “RC” label (Resource Conserving) found in API classification means the oil has passed some additional tests for the beneficial effects on fuel consumption and emissions.
In European ACEA classifications, equivalents are C1, C2, or C5. These will be low-friction, low SAPS oils that achieve the fuel economy performance requirements for approval, as well as meet emission limits, particularly of importance for DPF filter-equipped engines.
That said, a label does not mean all that much by itself. The most important thing is to ensure that the oil meets the vehicle manufacturer’s specifications to get the performance benefits mentioned.
This article was created in cooperation with Junipertrade – engine oil wholesale and lubricants for passenger cars, trucks, and agricultural machinery.