The difference between 10w-30 and 5w-30 oil is the thickness of the oil during cold weather conditions, 5w-30 being the thinner of the two and therefore recommended for colder operational climates. Engine oil is rated on a viscosity scale by the Society of Automotive Engineers, which determines its cold- and warm-weather rating; the cold rating is indicated by a “w” for winter.Know More
Automotive oil manufacturers currently produce multigrade oil, which means it behaves differently at different temperatures. The Society of Automotive Engineers grades oil based on its performance at different temperatures by measuring the amount of time it takes to flow through a length of tube. Oil that takes 30 seconds earns a grade of SAE 30. Lighter-weight oil passes more rapidly through the same tube but thickens under colder temperatures, allowing for better performance. Therefore, an SAE 10w-30 performs like grade-30 oil during warm temperatures and grade-10w oil in colder climates.
In the past, oil manufacturers only offered single-grade oil that needed to be changed for seasonal operations. Heavier oil that offered good performance in the summer would have to be changed for lighter-weight oil for easier starting in the winter. A single-grade oil has one number to signify its viscosity, such as SAE 50 or SAE 10w.Learn more about Engine Oil
The main difference between 10W-30 and 10W-40 motor oil is that 10W-40 has a higher viscosity, which means that it will remain thicker at higher temperatures than 10W-30. Viscosity means a liquid's resistance to flow, and normally a higher viscosity is a good thing for oil, as it acts as a better lubricant and creates a stronger seal.Full Answer >
The two oil types differ in their high temperature viscosity, and 10w40 is thicker than 10w30 when it comes to high temperatures. Before multi-grade oils were formulated, car owners typically used 10w30 for its wintertime flow properties, while relying on the 10w40 for the summertime when temperatures warmed up.Full Answer >
Viscosity describes a fluid's resistance to flow. The thicker the fluid, the slower it flows and the higher its viscosity. The viscosity of a lubricant such as oil affects how it reduces friction and transfers heat.Full Answer >
The additives that manufacturers add to motor oil break down over time, making oil changes necessary, according to HowStuffWorks. The oil also picks up dirt and debris from the wear of the engine. While the filter removes foreign material for a while, if it gets plugged the oil bypasses it.Full Answer >