If you haven’t figured it out, your granddad’s SAE 30, 40 or even 10w40 motor oil doesn’t work in today’s modern engines. The reason for this is many fold but the top reasons is fuel economy, emissions, and power / performance of today’s engines.
Comparing modern engines vs those from the 1950’s, 60’s, and 70’s, today’s engines are more efficient, produce more power per liter or cubic inch and have increased fuel economy.
During the 1970’s the US Government incorporated CAFE standards for automobiles.  The Corporate Average Fuel Economy (CAFE) are regulations intended to improve the average fuel economy of cars and light trucks (trucks, vans and sport utility vehicles) by using lighter viscosity motor oils, manufactures were able to increase fuel economy by .5 miles per gallon. Furthermore in our own testing we have seen increases between 3-5% by switching over to light weight synthetic lubricants.
Typical light weight motor oils today are 5w30, 5w20, 0w30 and 0w20. The first number explains how an engine oil works in cold temperatures. The “W” stands for “Suitable for winter”. And the last number is the SAE viscosity at 100° centigrade (212°F.) The lower the first number the faster the oil will pump in cold weather. Using zero weighted oils help protect engines in cold weather as well as help improve fuel economy during the cold winter months. Because the motor oils are “Multi-grade” they can also protect engines at operating temperatures.

Light weight oils can reduce friction, pull heat away faster and increase performance.

Below is an article that was featured in the AMSOIL Dealer Magazine for September 2014. This article explains why lighter weight oils are being used in today’s modern engines.

Lighter-viscosity motor oils are only becoming more prevalent.

The forthcoming ILSAC GF-6 specification will introduce
the lightest category to date, SAE 16.

AMSOIL gasoline motor oil sales are shifting quickly from predominantly 5W-30 to a combination of 0W-20 and 5W-20 viscosity grades. Historically, motor oils have depended heavily
on a film of oil to keep engine parts separated, reducing metal-to-metal friction. The idea is that the oil film reduces friction between parts in motion, reducing wear and improving performance. Now the industry is working on reducing hydrodynamic friction between moving parts, something very different, which we will call fluid friction. Reducing fluid friction requires reducing internal friction of the lubricant. This is done through reducing lubricant viscosity. Some of you may be thinking, “Wait a minute, Dan, you just said that motor oils depend on a thin film of oil to reduce metal-to-metal friction and now you are saying that motor oils need to be thinner to reduce fluid friction. Have you been smelling solvents in the lab too long?”
Well, I have spent a lot of time in the lab over my career, but hopefully
have a few brain cells left to tide me over to retirement. Reducing fluid
friction depends on reducing the lubricant’s resistance to flow. For a given lubricant design, the higher the viscosity, the more energy it  takes for engine parts to move and for the oil to be pumped around the system. But there is a limit to how low you can go without allowing metal-to-metal friction. For those, like me, who grew up using 10W-40 in our vehicles the idea of yet another lower viscosity motor oil category is a little scary. This idea of reducing fluid friction to improve fuel economy can’t go below a 0W-20 right? Well, enter SAE 16. This evolution is continuing with the approval and introduction of the new API SAE 16 category. This is a lighter viscosity compared to the 20-weight category and, of course, all of this work is supporting the improvement in fuel economy outlined in new U.S. Corporate Average Fuel Economy (CAFE) standards.
Development of this new category was done by making the SAE 20
category tighter. Now the new SAE 16 viscosity category covers what
used to be the bottom end of the SAE 20 category where no commercial motor oils were ever designed. This lower viscosity category improves fuel economy further for engines designed for this lubricant. It reduces the fluid friction, and engines run more economically as a result. This motor oil is thinner and does not depend as much on the thin layer of oil for proper protection; rather,
oil additives play a bigger role in overall engine protection. This does
not mean that base oils are less important in overall protection; it is actually the opposite – outstanding base-oil lubricity is even more
important than before because the thin film of oil at operating
temperature just got thinner. What it also means is that high-tech motor oil additives are becoming an even more important part of engine protection than ever before.
These thinner motor oils will be covered by a new specification with the next round of gasoline motor oil specifications, which will be separated into two categories: GF-6A and GF-6B. The first category, GF-6A, will be focused on protection for gasoline direct- injection (GDI) engines, which will be the predominant engine platform
moving forward and will be backward compatible to older engines. GF- 6B, on the other hand, will not be backward compatible and will only cover the new SAE XW-16 category. These lubricants will be required for vehicle manufacturers to help meet the stringent CAFE requirements for new vehicles.
The engine protection requirements will be the same as those outlined in GF-6A, but GF-6B will use a different formulation to achieve these goals because of the ultra-low viscosity requirement.
Just when I was getting used to the idea of putting 5W-20 in my 2010
Ford Fusion, now I have to get my head around the potential of XW-
16 for a Honda Civic. When I was younger, I had a boss who had big
brass boots on his desk inscribed with the words, “Don’t bring me your problems, bring me your solutions.” New problems almost always create opportunities for new and innovative solutions. In this case, you can be sure that AMSOIL will move quickly from the problem to the solution.
– Dan Peterson, AMSOIL VICE PRESIDENT, TECHNICAL DEVELOPMENT

 

To get the best protection with lower viscosity motor oils be sure to use a high quality synthetic oil that is engineered to stand up to the rigors of today’s driving habits. Short trip driving, stop and go traffic and extreme temperatures throughout North America can cause an inferior motor oil to break down prematurely. AMSOIL formulates synthetic oils with the best additive technology combined with the highest quality base stocks that will ensure your vehicles and equipment will last and save you money.
Learn more about motor oils as well as filtration information by downloading the AMSOIL Motor Oil & Filtration Guild (G52)
When choosing the correct viscosity for your particular vehicles engine it’s always best to consult the AMSOIL automotive and light truck application guide. This online lookup allows you to find all the recommended products for your application.
You can also contact us directly. We would be more than happy to advise on the correct lubricants and filters for your vehicles and equipment. We have over 14 years experience with lubrication and AMSOIL products. We are your experts in lubrication.
To purchase AMSOIL visit the online store.
 
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