AMSOIL Frequently Asked Questions - Select Synthetics - AMSOIL Lubricants Dealer

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FAQs about AMSOIL Products, Lubricants, Oils, Filters
Frequently Asked Questions about AMSOIL products

Is AMSOIL Synthetic Oil safe to use in a brand new car?

With very few exceptions, AMSOIL Synthetic Oil is perfectly safe to use in both new and older cars, regardless of make or model, as long as the engine is mechanically sound. (One exception, for instance, might be Mazda vehicles that have a 'rotary' engine.*) In fact, many vehicles today leave the factory with synthetic oil installed as the initial fill.

I personally use AMSOIL 100% Synthetic Oil in all my vehicles, new and old, including a 2014 Kia Sorento EX and a 2000 Jeep Grand Cherokee Ltd. in which we have been using synthetic oil since it was new (it now has almost 400,000 km on it and the engine still runs like new).

Though Mazda doesn’t recommend it, there are people who have run synthetics in a car with a rotary engine with no problems whatsoever.

Could using AMSOIL Synthetic Oil void my new car warranty?

Absolutely not. Vehicle manufacturers recommend using motor oils meeting certain viscosity grades and American Petroleum Institute (API) service requirements.

The manufacturer is required to cover all equipment failures it would normally cover as long as the oil satisfies the requirements and was not the cause of the failure.

AMSOIL Motor Oils meet or exceed these requirements. Even so, AMSOIL has its own limited warranty, protecting you even further.

AMSOIL GuaranteeIn addition, the federally mandated Magnuson-Moss Act states that a manufacturer may not require the use of a specific brand of aftermarket product (including motor oil and filters) unless it’s provided free of charge.

Do I need to wait for the engine to ‘break-in’ before switching to AMSOIL?

One of the myths surrounding synthetic oil is that new engines still require an initial break-in period with conventional oil before you can switch to synthetic. However, with most modern engines today, this is simply no longer the case.

Today’s engines are built to much higher/tighter manufacturing tolerances (due to more accurate and precise machining and assembly) than the ones in older vehicles, eliminating the need for a long break-in period with conventional oil. As already mentioned, many vehicles today leave the factory with synthetic oil installed as the initial fill.

Even if synthetic oil wasn’t the ‘initial factory fill’, you do not need to wait before switching over to AMSOIL synthetics.

How frequently should I change the oil in my car?

The question of how frequently you should change your oil depends on a number of different factors.

Some of these factors include:

The ‘type’ of oil used: Synthetic Oil allows for significantly longer drain intervals then Conventional Oil – especially high quality ‘extended drain’ synthetic oils such as AMSOIL’s Signature Series and XL Series synthetic oils.

Driving conditions (normal or severe): For instance, frequent city driving or repeated short distances driving; driving in very cold, very hot, dusty, or sandy environments; frequent towing, hauling, or plowing; excessive idling; etc, will require more frequent oil changes. (Check your Owner’s Manual for more info on severe driving conditions.)

The make, model and year of your car: Because of technological advances in modern engine materials, design and built, as well as significant improvements in engine oil formulations, recommended oil change intervals for new vehicles have become considerably longer.

The bottom line is: The recommended oil change interval will be different for different people.

There is no magical one-size-fits-all number.

One thing that is certain, however, is that the 5,000 km (3,000 miles) oil drain interval recommendation is a thing of the past. For instance, with AMSOIL’s Signature Series oil, you can extend them to as much as 40,000 km (25,000 miles) under normal driving conditions.

Here are a couple of informative 'third party' articles on the subject.

Stop Changing Your Oil

Lube Report: ExMo Extends Oil Drains to 15,000 Miles

And going back in time a little, here's an interesting article on synthetic oil in a 1976 issue of Popular Science.

The big debate over synthetic oils for your car

P.S. When changing your oil, don’t forget to also change your Oil Filter as well. You should change it at every oil change. If you extend your oil change intervals beyond the Oil Filter’s maximum recommended service interval, you will have to change it more often.

AMSOIL Ea® Full-Flow Oil Filters feature advanced full-synthetic media that traps and holds a greater amount of small, wear-causing contaminants compared to conventional filters. They provide extended service intervals (up to 25,000 miles/one year) for increased convenience, while helping reduce engine wear. They also have one of the best efficiency ratings in the automotive/light-truck market.

I was always told to change the oil every 5,000 km (3,000 miles) if I wanted to properly maintain my vehicle. How is it possible to drive 40,000 km (25,000 miles) without an oil change using AMSOIL Synthetic Oil?

AMSOIL synthetic oils provide extended-drain performance because they resist breakdown better than conventional oils.

AMSOIL oils are formulated to prevent the formation of performance-robbing deposits and resist volatilization (burn-off/evaporation), which alters viscosity and increases oil consumption.

Furthermore, AMSOIL synthetic oil’s superior additive package, a key element in the oil’s ability to function, holds up under engine stresses, remaining serviceable for the full recommended drain interval.

For those seeking the best value, AMSOIL Signature Series oil is guaranteed for 40,000 km (25,000 miles) or one year in mechanically sound engines in normal service and 24,000 km (15,000 miles) or one year in severe service.

In fact, some AMSOIL diesel oils carry drain interval recommendations of up to 80,000 km (50,000 miles).

AMSOIL coined the phrase “extended drain interval,” and it’s been validated by nearly 40 years of industry testing and millions of over-the-road miles.

What SAE viscosity grade of oil should I use in my car?

All vehicle manufacturers today recommend the use of 'multi-grade' oils. To find out which multigrade oil is recommended for your particular vehicle, you should consult your owner’s manual.

The manual might list only one grade of oil for use in all temperature ranges, or it might list a few different grades of oil to choose from based on ambient temperatures.

Now because these are the oil grades that the manufacturer ‘recommends’ for use in your vehicle, does this mean that they are the only grades that can be used in the vehicle’s engine? Well, not exactly. First, let’s look at what these numbers actually mean.

The viscosity of a fluid describes its internal resistance to flow – the thicker the oil, the higher its viscosity. Let’s use a 5W-30 multi-grade oil as an example. The first number (5W) is the 'cold' viscosity rating of the oil, the ‘W’ stands for winter, and the last number (30) is the 'hot' viscosity rating of the oil. Therefore, when the oil is cold (e.g. in sub-zero temperatures) it has a rating of 5W. When the oil is hot (e.g. circulating in a hot engine) it has a rating of 30.

What this means is that a 0W-30, a 5W-30, and a 10W-30 multi-grade oil will all have essentially the same viscosity (thickness) when circulating in a hot engine but will have a completely different viscosity when cold.

Note: The viscosity grade numbers (e.g. the 5W and the 30 in a 5W-30 multi-grade oil) are simply a rating representing the viscosity range of the oil. They are NOT the actual viscosity of the oil. The viscosity of oil is temperature dependent. In other words, a particular grade of oil will have a different viscosity (thickness) at different temperatures.

Therefore, the question as to which oil viscosity grade can be used in your vehicle’s engine will depend on a number of different factors, for one, the type of climate you will be driving in. If you live in a very hot climate you could use a higher viscosity grade oil (10W-30 for instance), and if you live in a much colder climate you could use a lower viscosity grade oil (0W-30 for instance). However, the recommended viscosity grades should do just fine in all climates.

oil viscosity grades chart

Is SAE 0W-XX too thin a viscosity oil for HIGH ambient temperature operation?

Not at all. As already mentioned, the viscosity grade numbers (e.g. 0W, 5W, 10W) are simply a rating representing the viscosity range of the oil. They are NOT the actual viscosity of the oil.

The viscosity of oil is temperature dependent. At higher temperatures, the oil becomes thinner (viscosity decreases). At lower temperatures, the oil thickens (viscosity increases). Therefore, just like any other grade of oil, an SAE 0W grade oil will have a different viscosity/thickness at different temperatures – thicker when cold, thinner when hot.

With a multi-grade oil, it is the second number (e.g. the 30 in a SAE 0W-30 multi-grade) that will determine the thickness of the oil at operating temperatures not the first number (0W). What this means is that a 0W-30, a 5W-30, and a 10W-30 grade oil will all have essentially the same viscosity when circulating in a hot engine.

Additionally, you also need to understand that at ambient temperatures (yes, even at HIGH ambient temps), ALL grades of oil are too thick/viscous (yes, even an SAE 0W grade oil is too thick). In other words, an SAE 0W grade is thicker at ambient temperatures than an SAE 30 grade is at operating temperatures. It is only after the engine warms up, heating up the oil, that the oil reaches its proper “hot” viscosity (thickness).

(For more on Motor Oil Viscosity, see: "What Is Oil Viscosity?")

AMSOIL Frequently Asked Questions

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