When trying to find the best motor oils for a vehicle, there are a wide range of regular and synthetic motor oils to choose from. While vehicles initially used conventional motor oil to lubricate and protect critical engine parts, the development of synthetic motor oil in the lab has led to unprecedented performance levels in the oils of today.
But how do you know when which motor oil type to use? This decision comes down to the age of your vehicle and your level of driving activity. Routine driving, such as commuting, might only call for a conventional oil, while more intense driving, such as hauling loads or trailers, requires a more robust synthetic blend. Ask a mechanic for their recommendation when deciding on an oil type to use.
Conventional motor oil
Conventional motor oils use base oils blended with different chemical additives to meet the basic needs of vehicle engines. Coming in a range of viscosity levels, the available oils range in quality from adequate to high-quality lubricants.
Most often used in late-model vehicles driven in routine driving situations, such as commutes, errands, or vacation driving at cruising speeds, conventional motor oil provides the perfect low-mileage oil. Newer vehicles require more specialized synthetic oils.
Synthetic motor oil
Synthetic motor oil uses a specially blended formula developed by researchers in a lab environment. Most often such oils use a variety of high-performance additives to provide a high level of engine protection at startup and while running.
In addition, the best synthetic oils offer protection against heat build-up, enhance engine durability, and help clean engines of deposits.
Synthetic blend motor oil
Recommended for engines that carry regular heavy loads, operate at high RPMs in day-to-day activity, and tow trailers, synthetic blend motor oil consists of synthetics developed in a laboratory mixed with more conventional oils. The oil type provides some of the best low-temperature properties while adding oxidization-resistant properties not seen in many conventional motor oils.
High-mileage motor oil
High-mileage motor oils are specially blended for vehicles that have 75,000 or more miles on the odometer. The best high-mileage motor oil uses unique additives to help seal oil leaks around aging seals, reduce oil burn-off, and restore engine compression.
Check with a mechanic before using a high-mileage motor oil, because some older model vehicles work best when using a regular synthetic motor oil.
Motor oil ratings
Motor oil ratings represent the best way to determine which oil is the correct one for your vehicle. The most common type of oil today, multiviscosity, comes with labeling that designates how the oil performs at certain temperatures. For example, a 5W-30 flows better at a lower temperature than a 10W-30 oil. In both cases, the number before the W represents the viscosity rating at which the oil performs at colder temperatures and at startup. The number after the W, which stands for winter, shows the performance level of the oil at high temperatures. A mechanic can give the best advice as to which oil viscosity level to use.
This article originally appeared on YourMechanic.com as What Is the Difference Between Regular and Synthetic Motor Oil? and was authored by Cheryl Knight.