How to Choose the Right Engine Oil for Your Vehicle

Purchasing proper engine oil for your vehicle may appear a simpler task than it is. You need to be knowledgeable of your car's oil requirements to maintain efficiency in your engine.

Labels placed on quarts of motor oil indicate the oil meets certain industry standards. A starburst symbol of the American Petroleum Institute signifies the oil meets the Institute's standards through testing. A two-letter service designation of "SL" represents the oil has been through a series of laboratory and engine testing. Also listed on the oil container is the viscosity number as set by the Society of Automotive Engineers (SAE).

Quality engine oil is necessary for your vehicle to run properly, and to maintain the life of the engine. You want to obtain the best for your vehicle, and an economical price, as well.

Viscosity Rating

A viscosity rating designates the thickness of engine oil. For instance, a 10W-30 oil indicates the viscosity of the fluid when cold, with "W" designating that the SAE approves the oil for lower winter temperatures. A 10-weight is thinner than a 30-weight, and favorable when cold, since a thinner engine oil permits an easier engine start and reduced tension. The second number, "30", indicates oil viscosity is heavier and offers more protection in warmer temperatures.

During colder temperatures, the oil must be resilient to thickening so it can flow smoothly through all the moving engine parts. If the oil is too thick, then the engine needs a greater amount of power to turn the crankshaft, which is partially immersed in oil. Oil that is too thick can make it harder to start the engine, decreasing fuel economy. A 5-weight oil is advisable for use in colder temperatures.

When a vehicle's engine is running, the oil heats up, so a viscosity rating with a higher second number indicates the oil will remain thicker at high temperatures than a viscosity having a lower second number.

Whether a thicker or thinner oil performs best in your engine is a determination made by the automaker. Owner’s manuals for vehicles provide necessary data regarding the proper viscosity oil to use, and some include information on which conditions are best for various viscosities.

Viscosity Index

Viscosity index is the oil's resilience to thinning during rising temperatures. Even though a higher second number is beneficial, the oil must be full-bodied, as well, to endure for many miles until the next change. Oil has a tendency to lose viscosity from the action between close-fitted metal surfaces of the moving engine parts. Resilience to viscosity loss is essential to allow the oil to preserve the lubricating layer between those parts.

Comparison of Engine Oils

Varieties of oils with a broad range of viscosities are available to meet all types of specific uses, such as for new vehicles, higher-mileage vehicles, heavy-duty vehicles, and SUVs.

Premium standard oils

Commonly used in new cars, and it is available in several viscosities. Carmakers recommend a rating of 5W-20 or 5W-30 in colder temperatures and 10W-30 for higher temperatures. These ratings encompass nearly all light-duty vehicles. It is critical to change the oil and filter on a consistent basis for the efficient running of your car. Every 4,000 miles or four months is a good rule to follow.

Synthetic oils

Oils created for more advanced technology engines are full synthetic oils. These oils must pass rigorous testing so they will deliver greater performance over a longer period in protecting against engine deposits and assured viscosity index. At higher temperatures, they retain a high lubricating ability, and at lower temperatures, a smoother flow. Synthetic oils cost more than standard oils but are not required in all engines.

Synthetic blends

These blends are a combination of synthetic oil and organic oil, created to safeguard engines with heavier loads at higher temperatures. This makes these oils less unstable and less evaporative, increasing fuel economy. Drivers of SUVs and pick-ups who desire more substantial load protection use these affordably priced blends.

Higher mileage oils

More than half of the vehicles on the road today are creeping toward 100,000 miles on their odometers. Oil refineries have recognized the need to produce specific oils for use in higher mileage vehicles. These oils also contain seal conditioners that flow into the cavities of the crankshaft seals to restore their form and increase elasticity. Higher mileage oils have greater viscosities, which improves performance and produces a smoother running engine.

Use Recommended Oil

By not using the type of oil approved by the automaker or the recommended oil viscosity for your vehicle, you risk voiding your warranty if there is engine damage. The warranty can be voided by using a heavier oil weight in a car that advises lighter weight oil, or using synthetic oil not approved by the automaker.

The Importance of Regular oil Changes

Engine oil becomes full of pollutants and contaminants over time. These impurities remain inside the engine and can create residues that produce considerable corrosion. Contaminated oil has reduced lubrication and ultimately creates an overworked engine and excess heat, possibly causing a thermal breakdown in the engine oil and reduced oil flow. Consequently, the engine must work harder, which leads to increased engine deterioration. Regular oil changes will help keep your vehicle's engine operating more efficiently over a longer period.