AMSOIL Frequently Asked Questions - Select Synthetics - AMSOIL Authorized Dealer

Main menu:

FAQs about AMSOIL Products, Lubricants, Oils, Filters

Frequently Asked Questions about AMSOIL

How long have AMSOIL Lubricants been on the market?

AMSOIL products have been available since 1972, when AMSOIL 10W-40 Synthetic Motor Oil became the first synthetic motor oil to meet American Petroleum Institute (API) service requirements. Today, we manufacture synthetic lubricants for virtually all automotive, powersports, commercial and industrial applications.

How do AMSOIL synthetic motor oils compare to other motor oils?

The importance of using good-quality oil in an engine cannot be overstated. AMSOIL Synthetic Motor Oils consistently outperform conventional and other synthetic oils in virtually every category of performance, including wear protection, extreme high- and low-temperature performance, foam control, viscosity retention, rust and corrosion protection, volatility and fuel economy.

While other brands may provide good performance in some of these areas, AMSOIL synthetic motor oils consistently perform at the top in every category. Drivers can have confidence knowing that AMSOIL synthetic motor oils provide maximum performance and protection.

Can AMSOIL synthetic oils be mixed with other oil brands or type?

Yes. AMSOIL Synthetic Motor Oils are compatible with other conventional and synthetic motor oils. Mixing other oils with AMSOIL motor oils, however, will shorten the oil’s life expectancy and reduce its performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Mixing other oils with AMSOIL motor oils will also void the AMSOIL limited warranty.

For more on this, see my article: Can I Mix Different Motor Oils?

Will synthetic motor oils cause older engines to "leak oil"?

No. That is a myth. Synthetic motor oils do not cause engines to leak oil. In fact, AMSOIL Synthetic Motor Oils are fully compatible with modern seal materials and is properly formulated to condition seals, keeping them pliable to prevent leakage.

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 factory fill.

Synthetic oil is superior to conventional oil and significantly outperforms it on all counts. Synthetics deliver superior protection and performance in temperature extremes (hot or cold), keep your engine cleaner by significantly reducing the formation of sludge and varnish, resist oxidation and acid formation, and provide unsurpassed friction reduction and wear protection for extended drain intervals.

I personally use AMSOIL 100% Synthetic Oil in all my vehicles, new and old, including a 2019 Kia Sorento SX, a 2008 Chevy Cobalt, and a 2000 Jeep Grand Cherokee in which we have been using synthetic oil since it was new (it now has 400,000 km on the original engine, which still runs great).

* 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?

No, using AMSOIL Lubricants will absolutely NOT void your new car warranty.

Most vehicle manufacturers simply recommend using a motor oil meeting a certain SAE Viscosity Grade (e.g. SAE 5W-20) - some Owner's Manuals will give you a few different Viscosity Grades to choose from - and a minimum API Service Classification (e.g. API SN) that the oil should meet.

Some of them might list a few other Motor Oil Specifications - such as ILSAC, ACEA, or an OEM spec. that the oil has to meet for your new car warranty to remain intact.

That said, 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.

Not only do AMSOIL Lubricants meet or exceed these requirements, AMSOIL also has its own Limited Warranty, protecting you even further. AMSOIL is WARRANTY SECURE

In 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.

For more see: AMSOIL Runs On Freedom

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

One popular myth about 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 new 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 "factory fill" motor oil.

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

For more, check-out my article: When Should I Do My First Oil Change?

What are the differences between AMSOIL "OE" Series, "XL" Series and "Signature" Series Synthetic Motor Oils?

AMSOIL OE Series full synthetic oils are recommended for "manufacturer-recommended" oil change intervals.

AMSOIL XL Series full synthetic motor oils are recommended for extended drain intervals of up to 20,000 km (12,000 miles) or one year (whichever comes first) - under normal (ideal) driving conditions.

AMSOIL’s Signature Series full synthetic oils are recommended for extended drain intervals of up to 40,000 km (25,000 miles) or one year (whichever comes first) - under normal (ideal) driving conditions.

AMSOIL’s Signature Series premium top-tier 100% full synthetic motor oils are formulated with better base oils and more robust additives, allowing longer extended drains than AMSOIL OE or XL Series synthetic oils.

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 and different cars. 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 up to 40,000 km (25,000 miles) under normal driving conditions.

For more on this, see my article: How Often Should I Change the Oil In My Vehicle?

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 lubricants 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, our Signature Series oil is guaranteed for up to 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 over 45 years of industry testing and millions of over-the-road miles.

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

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 (SAE 10W-40 for instance), and if you live in a much colder climate you could use a lower viscosity grade oil (SAE 0W-20 for instance).

For a much more detailed explanation, see my article: What Oil Viscosity Grade Should I Use In My Vehicle?

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).

I recommend you read all three of my articles on Viscosity, starting with: "What Is Oil Viscosity: The Basics"

Why do some European vehicles have different oil formulation requirement than North American vehicles?

The primary reason has to do with the different emissions systems and exhaust treatment devices used on the vehicles in those different markets, which are due to different emission standards and regulations.

For instance, some European emissions systems and after-treatment devices, such as Diesel Particulate Filters (DPFs), are very sensitive to the SAPS (Sulfated Ash, Phosphorus and Sulfur) content of the oil. Consequently, some of those engines in Europe require lower SAPS content to keep these systems functioning properly. The ACEA and OEMs realized the importance of using motor oil formulated with precise SAPS levels to protect those emission systems, and lower limits were established in 2010.

SAPS comprise a significant part of a motor oil additive content. Sulfated Ash is not added to oil, it is the result of additives in the oil burning and creating ash. The additives that can produce ash are most commonly used to achieve a higher Total Base Number (TBN), but also help in other areas, like anti-oxidancy, anti-wear, cleanliness, and soot handling. Phosphorus provides anti-wear properties and further anti-oxidancy, while Sulfur contributes anti-oxidancy, anti-wear properties, and engine cleanliness.

It should be pointed out that reducing the SAPS levels in motor oils also reduces the length of time the oil can remain in service (the maximum drain interval).

AMSOIL's European Formula Motor Oils come in Low-, Mid-, and Full-SAPS.

Why was the Zinc content in modern motor oils reduced?

To comply with the Environmental Protection Agency’s (EPA) tightened emissions legislation in the U.S., car manufacturers from around the world were forced to use technology to bring their cars in line with the law. As a result, catalytic converters were introduced in 1975. The problem is, catalytic converters happen to be very sensitive to the levels of ZDDP (Zinc Dialkyl Dithiophosphates) used in todays motor oils.

The problem is, excessive levels of phosphorus in ZDDP happen to be harmful/poisonous to catalytic converters. Generally, high levels of ZDDP result in volatile phosphorus being transferred from the combustion chamber to the catalytic converter. Phosphorus can blind over the catalytic reaction sites in the converter, making it less efficient in turning carbon monoxide (CO) into carbon dioxide (CO2).

The EPA mandates that catalytic converters operate as designed for more than 100,000 miles. As a result, phosphorus is limited for newer motor oil specs. The API and ILSAC set phosphorus limits to 0.10 percent weight (1000 ppm) in 1996, which was further reduced to 0.08 percent (800 ppm) in 2004, where it remains today.

What is ZDDP exactly?

ZDDP (Zinc Dialkyl Dithiophosphates) is the most commonly used anti-wear additive in motor oils. It contains both zinc and phosphorus components that work together to provide anti-wear protection and minimize lubricant breakdown. Higher levels of ZDDP, provides the extra anti-wear protection required by older engines with flat-tappet cams and high-tension valve springs.

Under heat and pressure, ZDDP forms a microscopic glassy, phosphate layer that fills in the peaks and valleys of surface roughness, improves lubrication and forms a sacrificial wear coating. The purpose of that coating is to create a barrier, so that it is the ZDDP coating that wears off in use and not the parent metal on the expensive components in your engine.

ZDDP also acts as a corrosion inhibitor and does exhibits mild extreme-pressure protection.

Does the reduced ZDDP level in modern engine oil mean less wear protection?

No, not at all. Today's motor oils, such as those offered by AMSOIL, use several other anti-wear additives in their formulation that more than make up for the reduced ZDDP levels.

Futhermore, it is also important to note that many modern quality motor oil formulations, like the ones used in AMSOIL's premium formulations, use a newer type of ZDDP that maintains the prior level of wear protection of the engine while reducing the impact on the emission system. This advanced zinc/phosphorus additive keeps higher levels of phosphorus in the oil where it protects the engine instead of poisoning the catalytic converter.

What is the "NOACK Volatility" rating of motor oil?

The NOACK Volatility Test (ASTM D-5800) determines the evaporation loss of lubricants in high-temperature service. It is defined as the weight loss of the oil when it is held under iso-thermal conditions at 250˚C for a period of 1 hour under a constant flow of air and is expressed as a percentage of weight loss (g/100g). This test simulates or approximates the conditions in the area around the top piston rings of the engine.

Generally speaking, the higher the viscosity of the base oils used to formulate a particular blend, the less volatile the finished motor oil will be (smaller oil molecules evaporate more readily than larger ones). Additionally, the oil's NOACK Volatility rating will also be affected by the quality of the base stock and additives used in the blend.

Evaporation may contribute to oil consumption and can also lead to a change in the properties of the oil. The more motor oil vaporizes, the thicker and heavier it becomes, contributing to poor circulation, sludge formation, reduced fuel economy, increased oil consumption, wear, and emissions.

A lower NOACK Volatility percentage can also help reduce the amount of carbon deposits that accumulate in the intake track and on the back of the intake valves in GDI engines.

Many engine manufacturers specify a maximum allowable evaporation loss. AMSOIL premium synthetic motor oils have some of the lowest NOACK Volatility numbers in the industry.

Can you determine the condition of motor oil by its color?

Many people believe that you can determine when the motor oil in your vehicle needs to be changed based on its color - if it's black, or dark brown, it means that the oil is dirty and should be drained.

That is a myth, as is the related notion that you can identify spent oil by smell. The truth is, you cannot determine the condition of used motor oil based on its color (or smell).

A common misconception is that high quality motor oil should come out of an engine looking clean at the time of an oil change. Nothing could be further from the truth. If the oil is doing its job of cleaning the engine, then it should be dirty when it is drained. In other words, an oil getting darker only means that its doing its job of cleaning the engine.

Motor oil will start looking dirty a short time after it is put to use. In the case of diesel engines, the oil will look dirty within a few hours of operation. These are signs that the motor oil is doing its job of keeping soot, dirt, and other combustion contaminants in suspension to be carried to the filter or removed from the crankcase when the oil is changed. Motor oils have been formulated to hold these contaminants in suspension until they can be removed with an oil and filter change.

Furthermore, the continual exposure to periods of high heat naturally darkens motor oil. This is perfectly normal. Oxidation is another thing that can cause the oil to darken (and thicken), which again is perfectly normal.

Also, some additives in motor oil are more susceptible to darkening in the presence of heat than others, which is why one brand of motor oil will darken faster than another. For example, Molybdenum (Moly for short), a popular AW additive used in many motor oils, is black.

But what most often causes oil to turn black is soot - which is a by-product of combustion. However, since soot particles are less than one micron in size - most are about the size of a human virus (0.03 micron) - they typically don’t cause engine wear (unless they agglomerate into larger particles). For comparison, a human hair is roughly 70 microns in diameter.

Detergents and Dispersants will clean and remove these soot particles from the engine's surfaces and hold those contaminants suspended and dispersed in the oil. Dispersants cling to the soot particle and envelop it, preventing it from agglomerating and forming deposits on surfaces.

High dispersancy oils help ensure that the soot particles do not agglomerate. Plus they are formulated to cope with higher soot loadings of the oil. If soot particles do agglomerate into larger wear-causing contaminants, the Oil Filter will catch most of them and remove them from circulation.

Soot buildup only becomes an issue if/when the oil becomes over-saturated with soot (which will usually also result in increased oil viscosity).

Detergents and Ashless Dispersants also work to neutralize acids and the corrosive effects of combustion and oxidation bi-products.

A Used Oil Analysis (UOA) from a reputable lab is the only surefire way to determine the oil's condition and how much life remains in it. Chemically analyzing an oil sample reveals the condition of the oil, the presence of contaminants, fuel dilution and so on. [see: Oil Analysis]

What is the service life of AMSOIL Ea® Oil Filters?

When used in conjunction with an AMSOIL extended-drain motor oil, Ea Oil Filters designated with product code EaO are guaranteed for up to 25,000 miles/one year in normal service and up to 15,000 miles/one year in severe service. Ea filters designated with product code Ea15K are guaranteed for up to 15,000 miles/one year, whichever comes first, regardless of driving conditions.

It is recommended that all AMSOIL-brand oil filters be changed when the motor oil is changed. If oil other than AMSOIL is used, Ea Oil Filters must be changed according to the vehicle manufacturer’s recommendations.

Are AMSOIL synthetic Motorcycle Oils different from AMSOIL synthetic automotive oils?

Yes. In addition to the different additive packages used, withstanding extreme pressure, protecting against rust and withstanding high temperatures, Motorcycle Synthetic Oils must be compatible with wet clutches.

AMSOIL Synthetic Motorcycle Oils are designed to meet the unique frictional requirements necessary for wet-clutch compatibility - meetting the JASO MA2 friction requirements for wet-clutch applications - and provide maximum protection and performance in these applications.

NOTE: Wet clutches are immersed in motor oil in order to cool the clutch plates. They are often found in motorcycle applications, and they require fluids with certain frictional requirements to promote smooth shifting and clutch engagement. Dry clutches require no lubrication.

What is the oil change interval for AMSOIL Synthetic Motorcycle Oils?

AMSOIL Synthetic Motorcycle Oils are engineered to provide outstanding protection for up to twice the manufacturer’s recommended change interval or one year, whichever comes first.

Unless using an AMSOIL Ea Motorcycle Oil Filter, change the filter based on the manufacturer’s recommended interval.

For Big Twin Harley-Davidson transmissions, follow the Harley-Davidson recommended drain interval for synthetic oil up to 20,000 miles or one year, whichever comes first.

For a "Glossary of Acronyms and Common Terms" - CLICK HERE