🔍 Key Concepts

• Viscosity and how it affects oil flow at low vs. high temperatures • The effect of high-viscosity lube oil on engine starting and bearing lubrication • Typical causes of increased oil consumption in diesel engines

💭 Think About

• Think about what happens to very thick oil when an engine is cold and you try to pump it through narrow passages. • Consider whether high viscosity oil would be more likely to burn off/escape past rings or less likely, compared to thinner oil. • Ask yourself whether friction losses in the engine generally increase or decrease when the oil is thicker than recommended.

✅ Before You Answer

• Verify how cold starting performance is affected by oil that is too thick. • Check whether oil consumption usually increases with thinner (low viscosity) or thicker (high viscosity) oil. • Confirm whether friction and pumping losses go up or down when lube oil viscosity is higher than specified.