Thursday, November 8, 2007

Motor Oil: Making the Grade

Motor oil is used to lubricate all sorts of internal combustion engines. Lawn mowers, automobiles, airplanes, and industrial engines alike all share the needs that motor oils fulfill, namely, lubrication, cleaning, corrosion prevention, and cooling. The metal parts that exist in all types of engines must possess a coating of oil in order to decrease the amount of friction created when all the parts are moving together. A lack of lubrication could cause metal on metal contact, resulting in irreversible harm to the engine. Oil companies such as Triple Diamond Energy Corp provide the necessary petroleum that goes into the production of the motor oil necessary in all of today’s engines.

The Society of Automotive Engineers, abbreviated as SAE, established a coding system for grading motor oils according to their kinematic viscosity. Kinematic viscosity can be observed as the thickness a fluid maintains under movement. The oils are watched at a constant temperature of 100 degrees Celsius or 212 degrees Fahrenheit, and graded according to how its viscosity holds up and assigned an SAE number of 0 through 70. These oils are commonly referred to as single-grade motor oils and their viscosity changes over varied temperature ranges. These oils are also tested at winter temperatures and are expected to behave somewhat similarly in frigid temperatures as they do in hot ones. The winter test assigns the letter “W” to the oil. A 20 grade motor oil at a higher temperature should behave correspondingly to a 20W oil. The single grade motor oils are mostly used in engines that do not have a breadth of temperature changes. Single grade motor oil is sufficient for use in lawn mower engines, for instance.

Most vehicles expose their motor oil to a large temperature range, from cooler temperatures at start-up in winter season to hot temperatures in a fully warmed up engine at the height of summer. For this reason, most automobiles need motor oil that will exhibit the same viscosity over a large range of temperatures. Special polymer additives called viscosity index improvers are added to oil so this sameness of viscosity is achieved. These motor oils are commonly called multi-grade because of this singular ability. They are able to have two levels of viscosity denoted by two numbers in their grade. The first number is associated with a “W” or winter temperature viscosity. The second number (without the W) is assigned to show the oil’s viscosity index during hotter temperatures. For most newer automobile engines, a 20 weight oil (the second number) is most desirable because its thinness allows it to freely flow and protect the engine during the crucial start up and warm up periods where a car’s engine is most vulnerable.

About the Author: Bob Jent is the president of Triple Diamond Energy Corp. Triple Diamond Energy specializes in acquiring the highest quality prime oil and gas properties. For more information, visit

1 comment:

Rick said...

What I have is a question, rather than a comment. We are about to take some vehicles up north for a cold weather training test. I have been tasked with preparing these vehicles for the exercise. Normally the systems use 15W40 oil, and operate at a tempter of 70 - 80 C. The engines are four cycle V 12’s with a prestart oil lubricating / priming system.
What recommendations would you make in order for these systems to survive the conditions of northern Michigan’s winter?
Thank you for your time and thoughts on this matter.