Motor Oil Guide

What’s in a Quality Motor Oil?

Quality motor oils are formulated with premium base oils, synthetic base oils, or a combination of the two. They are blended with a high performance additive package to improve the characteristics of the oil. Performance additives enable the base oil to protect and clean the engine, thereby extending its life. They include:

  • Detergents — Clean the engine; prevent rust, corrosion, and deposits adhesion.
  • Dispersants —Remove soot and sludge and suspend it in the oil, keeping it from building up. The dirt is then removed from the engine at the next oil change.
  • Anti-wear Additives — Prevent metal-to-metal contact between engine parts by forming a protective film.
  • Antioxidants — Prevent oxidation, delaying the degradation of your oil
  • Friction Modifiers — Reduce friction between moving parts, helping improve fuel economy
  • Rust and Corrosion Inhibitors — Prevent engine corrosion
  • Extreme Pressure Additives — Decrease wear of parts exposed to high pressure
  • Viscosity Index Improvers — Additives used to decrease viscosity-temperature dependence of lubricants.
  • Pour Point Depressants —Improve flow for cold temperatures
  • Anti-foaming Agents — Reduce foaming and stabilizes


Selecting the Right Motor Oil Based on Viscosity

Your Waterford Oil representative can help you select the right oil to perform at the highest level for any engine under any conditions.

The first step in selecting the right oil is determining the right SAE viscosity grade. The SAE (Society of Automotive Engineers) classifies oil based on how viscous it is, or the oil’s resistance to flow at different temperatures; the more viscous (thicker), the more resistance to flowing.

As the temperature drops the oil thickens. Selecting the proper viscosity grade ensures that the oil will flow to engine parts, reducing friction between metal surfaces, reducing high energy loss and surface wear. Viscosity should be high enough to form a protective film, but low enough not to increase energy loss.

SAE classifies oils in two ways, single-grade and multi-grade.

  • Single-Grade Oil: Or straight-weight oil is suitable for use within a specific temperature range; outside this range, its flow characteristics will not allow adequate lubrication. These have cold weather limitations.
  • Multi-Grade Oil: These oils are widely used because they allow for easy starting and pumping at low temperatures. Viscosity grades for motor oil are: 0W – 5W – 10W – 15W – 20W – 25W.

The “W” stands for Winter Service. These oils must meet viscosity and performance specifications that permit the oil to flow and pump at low temperatures. The lower the number the better the oil performs in cold operating conditions.


About the API Certification Mark Starburst

API starburstThis symbol can only appear on packaging if the motor oil meets or exceeds the performance standards set by the American Petroleum Institute. The symbol must appear on the front label of the motor oil container. An oil may be licensed to display the Starburst only if the oil satisfies the most current requirements of the International Lubricant Standardization and Approval Committee (ILSAC) minimum performance standard for this application (currently GF-5 for passenger cars). Many automobile manufacturers recommend oils that carry the API Certification Mark.

 About the API Service Symbol Donut

API donutThe API Service Symbol “Donut” is divided into three parts:

  • The top half describes the oil’s performance level.
  • The center identifies the oil’s viscosity.
  • The bottom half tells whether the oil has demonstrated energy-conserving properties in a standard test in comparison to a reference oil.

The top of the Donut shows the oil’s performance level for gasoline and/or diesel engines. The letter “S” followed by another letter (for example, SM) refers to oil suitable for gasoline engines. The letter “C” followed by another letter and/or number (for example, CI-4) refers to oil suitable for diesel engines. These letters officially stand for “Service” and “Commercial.” The current API performance categories that can appear in the top part of the Donut are listed in the API Motor Oil Guide.

Contact us at 507-645-5659 or click here to discuss how Waterford Oil can meet your retail, commercial, or on-site lubricant service needs.