What Motor Oil does and Why it Matters..

Engine oils are complex mixtures of base oils and additive components designed to perform a variety of tasks: separating and lubricating moving parts, reducing engine wear, helping prevent deposits from forming on internal engine components, removing and suspending dirt and contaminants in the oil until these contaminants can be removed at the next oil change, cooling engine parts, enhancing engine fuel economy, providing protection over a wide temperature range and even helping to protect the emissions system. In other words, they do a lot more than just lubricate.
The right motor oil also helps protect your emissions systems. Catalytic converters can deteriorate over time and are expensive to replace. A high-quality motor oil helps protect the emissions system by minimizing its own impact on these devices. To assure base quality, always look for the American Petroleum Institute (API) Starburst and Donut.
Dirt is created inside your engine as part of the normal combustion process, so keeping engine components clean is essential. If your engine components and oil passages are dirty, your vehicle performance and efficiency suffer. Deposits also trap heat inside your engine like an insulating blanket. Which is why Pennzoil® motor oil doesn’t just help prevent sludge, it can clean up sludge in the first oil change. And when your engine’s running clean, you feel it.
By cleaning your engine:
Motor oils don’t just help prevent sludge, they’re designed to clear away sludge, dirt, debris and deposits from engine components and prevent blockages of important oil pathways. The oil locks up the dirt, rendering it harmless until it is removed at the next oil change. 
By reducing friction and minimizing wear:
Motor oils form a protective film over your engine components and have special additives between moving surfaces, preventing contact and reducing drag. This helps your engine to operate as quietly and effectively as the day it left the factory.
By removing heat:
Motor oils carry heat from hot areas, such as around the piston rings where temperatures can top 600oF, helping to protect critical parts from intense heat.
By preventing corrosion and rust:
Motor oils protect your hardworking engine components from oxidation, and the resulting corrosion, over the normal oil-change interval. Our field test data shows that Pennzoil® motor oil stands up to extreme conditions and protects your engine from searing desert heat and harsh cold winter driving conditions.