Testers want to see if the oil will be thin enough for the engine to turn over, and to flow once the engine is running. At low temperatures, oil can thicken to the point that it actually solidifies. Hot testing is done at temperatures between degrees Celsius and degrees Celsius degrees Fahrenheit and degrees Fahrenheit , Fenske said. In these tests, the focus is on seal leakage and the ability of the oil to protect internal engine components when it's in a thinner state.
You may have noticed the numbers on oil bottles getting lower recently, with some oils even wearing a 0W rating. That's largely down to efficiency, according to Fenske. Thinner oils produce less friction, meaning less energy is required for rotating engine parts to move. Modern engines are designed to run with these thinner oils, so excess wear shouldn't an issue, Fenske noted.
Watch the full video for more details on how motor oil works. A lot of engineering goes into the numbers on each bottle of oil. Sign up to get the latest performance and luxury automotive news, delivered to your inbox daily! These three ratings cover just about every light-duty vehicle on the road, though this is changing as engines become more precise and fussy about specific types oil.
Full-synthetic Oil: These oils are made for high-tech engines. If these oils pass stringent special tests indicated by their labeling , it means they have superior, longer-lasting performance in all the critical areas, from viscosity index to protection against engine deposits. They flow better at low temperatures and maintain peak lubrication at high temperatures.
While excellent oil, synthetics are about three times as expensive as conventional oil and not always necessary for most engines. Use the owner's manual as a guide. If it doesn't call for synthetic oil, using it will only be an additional expense that may not add anything to the engine's performance or life. Synthetic-blend Oil: This is essentially premium conventional oil hit with a dose of synthetic. They're formulated to offer better protection during heavier engine loads and the associated higher engine temperatures.
These oils are popular with pick-up and SUV drivers because they do offer better protection, but usually cost only a fraction more than premium conventional oils. High-mileage Oil: More than 60 percent of vehicles on the road have more than 75, miles , kilometers on the odometer.
Playing to this growing market, oil refiners and labs developed high-mileage oils. Seal conditioners are added to the oil the oil can be synthetic or conventional to expand and increase the flexibility of internal engine seals. The conditioners are very precise and can benefit some engines while not affecting others. Oil weight can be a confusing term.
It does, however, have an important bearing on the life of your engine, and the type of oil you choose is intimately linked to manufacturer recommendations, the climate you live in and the type of driving that you do.
Oil weight is a term used to describe the viscosity of an oil, which means how well it flows at a specific temperature. The Society of Automotive Engineers SAE assigns a viscosity number, or weight, to oil based on its flow at degrees F, which is roughly the standard operating temperature for most motors. The higher the number, the thicker or slower flowing it is, which changes the nature of how it coats internal engine components and protects against heat and friction.
For example, a 5w30 oil weight rating means that on cold start-up — even at subzero temperatures — the oil flows like a 5 weight oil. However, once warmed up to degrees F, it functions as a 30 weight oil. This is why you would see something like this on the label: SAE 5W In a 5W for example, the number before the W describes the viscosity of the oil at low temperatures.
Multigrade oils such as SAE 5W and 10W are widely used because, under all but extremely hot or cold conditions, they are thin enough to flow at low temperatures and thick enough to perform satisfactorily at high temperatures.
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