#Low viscosity oil meaning iso
#Low viscosity oil meaning crack

Since the oil’s viscosity will change with temperature, most OEMs will supply a temperature–viscosity chart for their equipment to help ensure the correct viscosity is used depending on the operating temperature. In this case, the internal molecules gain more energy with the increase in temperature, lowering the internal friction within the fluid. Its viscosity will decrease, and the ice will turn to water. This is similar to a block of ice melting as temperatures increase. Likewise, as the oil heats up, it can become thinner. This means the oil will get thicker or more resistant to flow at lower temperatures. Similarly, for lubricants, as the temperature drops, the viscosity increases. Its viscosity can change depending on the influencing factors.Īs seen with the example of the water above, when the temperature decreases, the water can turn to ice. If water is at its freezing point (0☌), it can turn to ice but remains liquid at room temperature (around 20-30☌). For instance, water can assume other states depending on the temperature. Similar to the molasses and water examples above, different factors can affect the viscosity of a liquid. It will flow much faster than molasses (straight 50) with the same straw! The lighter-weight oil would also transfer heat and flow much faster than the heavier-weight (more viscous) oil. However, if a lighter weight (or less viscous) engine oil was used (such as a 0w20 or 10w30), then this is like someone trying to drink water (0w20) with a smaller straw. This would be equivalent to the user using a smaller straw for drinking molasses. The clearances also got smaller, and the engine oil was now required to flow faster, control the transfer of heat and contaminants and keep the engine lubricated.Ī straight 50 oil could not pass through the smaller straw at the speed it should. As such, most of these engines used a 50-weight (or straight 50) oil.Īs the technology evolved, the size of the engines got smaller. These engines had larger clearances for the oil to flow throughout the engine. We can draw this analogy to car engines over the last 30-40 years. However, getting the same liquid to the person using the straw would take longer if a thinner straw were used. Pulling the liquid from the cup will be easy using a big straw. While the oil analysis community is aware of the usual suspect conditions or events, some remain undiscovered or at least are not fully understood.You can also apply this to using a straw for drinking water from a glass. It's safe to say that viscosity will not change without a forcing event or condition that incites the change. You then must determine what this means and why it happened.

What's not so good is when viscosity moves suddenly with no obvious explanation or warning. After all, when viscosity has not changed, you can rightly conclude that the many known viscosity-altering factors are probably not occurring. This is why viscosity has become such an information-rich measure of used oil condition. The list of root causes that can alter a viscosity reading is quite extensive. Keep in mind that viscosity can go up, down or remain unchanged. If you are having trouble with a mineral oil losing viscosity at high temperatures, look at switching to a synthetic oil for the application.

The high temperatures can sheer/crack the oil molecules into smaller molecules, which causes a decrease in viscosity.

#Low viscosity oil meaning crack

Oils operating at extreme high temperatures can begin to crack thermally. Multi-grade oils aren’t the only ones that can thin due to high heat. Remember, exposure to high heat is the biggest factor in causing the sheer of the viscosity-index improver. During use, the VI improvers can sheer down and break apart, causing the viscosity of the oil to decrease. For example, if you are using a multi-grade SAE gear or engine oil such as a 10W-30, this oil contains an additive known as a viscosity-index improver. If this happens, it is a good idea to change the oil.Īnother way your lubricant could be losing its viscosity is through the loss or shear down of the viscosity-index (VI) improver.

#Low viscosity oil meaning iso

For instance, if you are using an ISO 220 viscosity gear oil but a lower viscosity gear oil (such as ISO 68) of the same brand is added in, this can lead to a sudden drop in the viscosity reading when the oil is sampled.Ī decrease in viscosity may also occur when non-lubricants like solvents and diesel fuel accidently get into the lubricant. However, the most common cause is adding in a lower viscosity fluid than what’s required. There could be several reasons for a downward trend or even a sudden drop in viscosity without warning. 'We have noticed that the viscosity of the oil in our circulating oil system has been decreasing.