Quicksilver Blog

By the Numbers: The Basics of Engine Oil Grades

It’s no secret that four-stroke engines require engine oil – and regular oil changes – to operate properly. Regardless of engine make or model, the best advice when choosing a grade, or viscosity, of engine oil is to follow the recommendations from the engine manufacturer, which should be printed in the service manual. It’ll list the appropriate grade for the engine and might list a couple of recommendations based on operating temperature and application.

The grade is identified using a numbering system. For instance, for many powersports applications, Quicksilver premium full-synthetic SAE 5W-50 ATV/UTV 4-Stroke Oil. The grade for this oil is “5W-50.” But what do those letters and numbers actually mean?

Let’s break it down.

SAE Viscosity Grades

The Society of Automotive Engineers (SAE) was founded in the early 1900s to provide unified automotive standards. Early members of the time, including Henry Ford, ultimately established a classification system for oil viscosity. Every oil grade will start with the three-letter abbreviation “SAE.”

What is Viscosity?

The viscosity of an engine oil refers to how easily an oil weight (thick or thin) flows at a specific temperature through a container or, in this case, your engine. The standard operating temperature of most engines is between 195 and 220 degrees F, and the assigned SAE viscosity number is based on a flow at 210 degrees F. When an oil is thin, it has a low viscosity and has two major low-temperature benefits: It flows easily and helps the engine start quickly.

Understanding Oil Grades

There are two types of oil grades – monograde and multigrade. SAE 30 would be a monograde oil. Quicksilver SAE 5W-50 is a multigrade oil. The two numbers represent two oil viscosities, with the “W” referring to “winter,” or low-temperature performance. During a cold start, the oil flows like an SAE 5 grade oil (thinner), but once the engine reaches its standard operating temperature of 210 degrees F, the oil functions like an SAE 50 oil (thicker). This offers the best of both oil grades because of its ultimate cold-starting performance and ability to protect against wear at peak engine operating temperature.

The Quicksilver “Good, Better, Best” System

In addition to providing various grades of oil for different applications, Quicksilver also offers a variety of engine oil formulas – including mineral, synthetic blend and full synthetic – that are optimized for marine or powersports engines. While they’re all formulated to provide premium protection and to meet the standards set by leading engine brands, the three oil types offer varying degrees of performance and different levels of beneficial additives. We call it the “good, better, best” system. Depending on your operating needs, application and engine performance, you can choose the formula that works best for you.

The Final Word

Quicksilver SAE 5W-50 ATV/UTV full-synthetic oil is a great all-season oil formulation, but you should always use the engine oil grade recommended in the service manual for your vehicle (Quicksilver also offers 5W-40 full-synthetic ATV/UTV oil and 10W-40 off-road oil for powersports). If operating in extreme low or high temperatures, or if you place additional stress on an engine by frequently hauling or towing heavy loads, playing in the sand dunes, or even racing, you may want to adjust your oil weight accordingly based on what the manufacturer suggests.

For boat engines and personal watercraft, it’s best to use an engine oil intended for marine use. Quicksilver four-stroke marine engine oils feature specialized additives that aid in preventing corrosion and maintaining peak protection while enduring the extreme demands of the marine environment.  

Regardless of whether your adventures take place on the trail, track or water, Quicksilver premium engine oils help provide peace of mind that your equipment is protected and can operate at its peak, so you can enjoy years of fun and excitement.