Which 30 Weight Oil Do I Use, 0W-30, 5W-30 or 10W-30?

We get asked this question so often that we have included this special page dedicated exclusively to answering the question.

AMSOIL 0W-30, 5W-30 and 10W-30 synthetic motor oils are ALL 30 weight oils. The answer is that ANY one can be used regardless if your vehicle owners manual says to use, for example, a 5W-30. "W" means winter. In winter weather the 0W oil will flow like a 0W oil, and the 5W will flow like a 5W oil and a 10W will flow like a 10W oil just until the engine warms up. In order to understand the differences one has to first understand that the numerical values given to these various weight oils are strictly empirical numbers. For example, 0W does not mean that the oil has no weight. That is one of the reasons why we say it is strictly an empirical number.

In order to determine the differences between the three oils one has to look at the kinematic viscosity of each lubricant. The kinematic viscosity is essentially the amount of time, in centistokes, that it takes for a specified volume of the lubricant to flow through a fixed diameter orifice at a given temperature.

Let's compare the kinematic viscosity of the three AMSOIL lubricants:

AMSOIL 0W-30 is 57.3 cST @ 40 deg. C, & 11.3 cST @ 100 deg. C

AMSOIL 5W-30 is 59.5 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C

AMSOIL 10W-30 is 66.1 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C.

As you can see from the data above the kinematic viscosities are extremely close. Therefore, whether you use the 0W-30, 5W-30 or the 10W-30 is strictly a matter of choice. With the small differences in kinematic viscosity you would be hard-pressed to detect these differences on initial engine start-up without specialized engine test equipment.

All three oils are excellent motor oils and ANY one can be used in a vehicle which requires either a 0W-30, 5W-30 or 10W-30 oil as well as in several other engine applications including an engine which recommends a 5W- 20 oil.

AMSOIL Series 2000 0W-30 Severe Service motor oil is one of the best synthetic lubricants AMSOIL manufacturers for gasoline engine passenger vehicles and light trucks. The molecular and chemical technology used to develop this oil was derived from AMSOIL's Racing Oil. It is a 35,000 mile/1-year motor oil. This is the same oil used by numerous police vehicles and severe duty fleets nationwide. In fact, many national racing teams use the 0W-30 for the qualifying event, then they change to the AMSOIL 20W-50 Racing Oil for the race. The extra horsepower and friction reduction from the 0W-30 often assists a race driver in attaining a better starting position. In fact, we know exactly which race teams use it, but cannot disclose that information.

This leads to the next topic: many people also ask us if the 0W-30 is too thin a viscosity oil for high ambient temperature operation. The answer is absolutely not! Thicker viscosity oils are not always necessarily better since in addition to its' various engine lubrication functions, an oil must also effectively transfer heat. Only about 60% of an engines cooling is performed by the engine coolant, and only on the upper half of the engine. The remaining 40% of an engines cooling is performed mainly by the engine oil.

Although a vehicle that is recommended to use a 30 weight oil can also use a 40 weight oil, it is usually not needed. You will gain absolutely no benefit from using a thicker viscosity oil if it is not needed. The only time we recommend a 40 weight oil, such as AMSOIL's 10W-40, to a customer in a passenger car or light truck application is if the vehicle's engine is excessively worn and consumes oil at a higher than normal rate or if the vehicle is being used for very severe duty, high load, high temperature applications.

We hope this brief discussion has answered your questions. If we have not sufficiently answered your questions or if you would like an additional explanation or recommendation for your specific application please email us using the link at the bottom of this page.

AMSOIL is the undisputed leader in synthetics.............

Since 1972, AMSOIL  Synthetics have proven to be the BEST.   AMSOIL also engineers and manufactures Ea Oil Filters with Nanofiber Technology which have a 25,000 mile/1-year service life as well as specialized filtration systems for commercial and fleet  applications in cars and light, medium and heavy trucks which can filter particles down to less than one micron (a standard full flow oil filter can only filter to 20-25 microns, and at a reduced efficiency) making oil changes virtually unnecessary and virtually eliminating engine wear.  These filters have been proven by millions of miles of over-the road trucks, construction equipment and fleet service.

• AMSOIL saves you time and money.  Let us show you how!
• The only 25,000 mile/one- year and 35,000/one- year motor oil in the world.
• Exceeds the most stringent performance specifications of all major U.S. and foreign automotive and truck manufacturers.
• Provides up to five-times the wear protection of other motor oils.
• Increases the life of your vehicle.
• Improves performance, fuel economy and efficiency.
• Diesel oil and filtration products designed to deliver 1,000,000 miles for over-the-road trucks before engine overhaul.
• Used by many national racing teams, fleets, police departments, construction firms and trucking companies.

We possess the skills, desire and knowledge to answer questions, solve problems, save money, improve efficiency, reduce downtime, maintenance costs and increase the durability and life of all of your vehicles.  We are based out of Oswego, IL  We personally serve the greater Chicago area and do business nationwide and in Canada.  Get to know us!  Customer service and satisfaction is our goal!  We will meet or beat any Amsoil program or current price and still give you great service.

We do not only run our business on the internet. We also have numerous commercial, industrial, trucking, construction, logging, marine, racing and many more accounts that we support and service on a regular basis. This provides us with excellent knowledge of the products, equipment and the business and the ability to respond immediately to any of your needs. We will use this knowledge and experience to help you get started so you too can achieve your goals. We have several regional distribution facilities across the United States to serve you quickly and efficiently.

Purchase AMSOIL products at wholesale prices with our Preferred Customer option. We never push you to become a dealer. That is an option that is open to you, but we will never bother you to become a dealer. If you do want to become a dealer, you won't find a more knowledgeable and skilled support group anywhere, which is very important as you use products and/or build your business.

Read through our website. There is no way we can put everything here so contact us with any questions.  If you decide to become an AMSOIL Dealer or Preferred Customer you will be joining, in our opinion, the most skilled and genuine AMSOIL group there is. We are hard working people just like you. We use the products in our own vehicles every day.  We will help you get started and provide you with the tools and information in order to be successful in this business or with  technical and product assistance to use AMSOIL products in your  vehicles.

If you would like a FREE packet of information regarding AMSOIL Premium Synthetic Motor Oils and Filtration Products plus much more tailored specifically for you, please e-mail us at dave@ultimateoiltechnology.com with your postal mailing address and your packet will be shipped promptly. Your name and address will be held strictly confidential. Please inform us of any special interests you have (diesel, motorcycle, marine, etc.) so that we can include material that addresses your application.  If you would like to download product brochures and technical information for yourself, send us an email telling us what your interest is and we'll send you links within this site where you can download loads of information!

AMSOIL is Proudly Made in the U.S.A.  AMSOIL is America's Oil.

Ultimate Oil Technology

Dave Spaay
Oswego, Illinois 60543
1-630-267-9163

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