Frequently Asked Questions

How can I purchase AMSOIL products?

Answer: Order through the AMSOIL Online Store. Become a Preferred Customer and purchase AMSOIL products at wholesale cost, which is approximately 25 percent less than retail price.

How long have AMSOIL lubricants been on the market?

Answer: 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, AMSOIL manufactures synthetic lubricants for virtually all automotive, powersports, commercial and industrial applications.

Becoming an AMSOIL Dealer

Are AMSOIL Dealers required to sell products?

Answer: No. Dealers only need to sell if they want to earn commissions and bonuses. Even then, Dealers are encouraged to operate their businesses according to their own goals and schedules; AMSOIL does not place any pressure on its Dealers to make sales.

How can i become an Amsoil dealer?

Answer: Use the online AMSOIL Dealer Form.

Is it possible to earn a residual income as an AMSOIL Dealer?

Answer: Residual income refers to money earned through indirect involvement. While it is possible to earn residual income as an AMSOIL Dealer, it requires an active group of successful personal group Dealers. Dealers who register other Dealers and help train them to succeed can continue earning commissions if they fall ill or cannot actively work their Dealerships for another reason. Building a successful personal group, however, requires a strong commitment to education and training.

Do Dealers purchase AMSOIL products at artificially high prices through the multi-level-marketing program?

Answer: No. Dealers and Preferred Customers purchase AMSOIL products at wholesale pricing.

Are there costs required to cancel an AMSOIL Dealership?

Answer: No. The AMSOIL registration fee is refundable if notification of intent is made to the sponsor or AMSOIL INC. within three days of the date shown on the application. Otherwise, a Dealer can simply choose not to renew his or her membership.

Synthetic Oil Basics and Switching From Petroleum to Synthetic

Can AMSOIL lubricants be safely mixed together?

Answer: Applications require specific lubricant properties to deliver maximum performance and protection. AMSOIL carefully tailors its synthetic lubricants under the strictest quality control standards to provide the required properties for the intended application. Mixing AMSOIL synthetic lubricants is not only unnecessary, it may lead to reduced performance and even equipment failure.

Automatic transmission fluids offer a perfect example. Some transmissions require lubricants that contain specific frictional characteristics to reduce, or eliminate, clutch slippage, while other transmissions may require different frictional requirements. Mixing fluids recommended for different performance specifications may lead to a host of problems, including erratic shifting and transmission failure.

In some applications, mixing lubricants may not lead to equipment failure, but it will reduce performance. For example, if AMSOIL Signature Series 5W-30 Synthetic Motor Oil is installed in a vehicle, and its owner adds AMSOIL OE Synthetic 5W-30 Motor Oil to top off the engine if Signature Series isn’t available, the vehicle will continue to operate perfectly; Signature Series and OE Synthetic Motor Oil share a similar chemistry, and formulations of the same viscosity can be safely mixed. However, mixing lubricants will shorten Signature Series’ life expectancy and reduce its performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

To minimize the risk of performance- and warranty-related issues due to improper mixing, AMSOIL does not recommend mixing AMSOIL synthetic lubricants.

What is the difference between synthetic and conventional oil?

Answer: Motor oil, whether synthetic or petroleum-based, consists of molecular chains of hydrogen and carbon atoms, referred to as hydrocarbons. Petroleum crude oil is a thick, highly flammable dark-brown or greenish liquid with high energy density. Many contaminating elements exist in this complex mixture of hydrocarbons, including sulfur, nitrogen, oxygen and metal components such as nickel or vanadium. Petroleum crude oil is the raw material used for a wide variety of petrochemicals, including solvents, fertilizers, plastics and lubricants.

The oil refining process separates the various types of molecules in the oil by weight, resulting in a concentrated batch suitable for manufacturing products such as gasoline, LPG, kerosene or lubricant base oils. The chemical composition of conventional motor oil can vary substantially depending on the raw crude oil refining process.

While petroleum base oils are refined, synthetic base oils are manufactured and can achieve a higher performance level. Synthetic oil is chemically engineered for a certain molecular composition with a tailored and uniform structure. Such fine-tuned control over the final molecular composition of synthetic oils is the key to their superior performance properties. Designing molecular structures in a planned and orderly fashion results in molecules, and end-products, that are far more stable than their refined petroleum counterparts.

What roles do additives play in motor oil performance?

Answer: Most lubricating oils have other chemicals added to improve the overall performance of the fluid. Chemical additives are used to enhance the beneficial properties of the base oil or to make up for oil deficiencies. For passenger car motor oils, base oil makes up 70 to 80 percent of the final product; the other 20 to 30 percent is comprised of additive chemistry.

Additives help lubricants stand up to extreme operating environments. Even the best base oil would not be able to protect as well against the effects of heat, shearing forces, chemical and water dilution, corrosion and wear particles. In short, additives make good base oils even better. They give good base oils the performance benefits consumers have come to expect, such as multi-grade performance, extended drain intervals and extreme-pressure performance.

Anti-wear Agents chemically react to form a film barrier that prevent metal-to-metal contact and wear.

Antioxidants reduce the tendency for oil to react with oxygen and reduce sludge buildup.

Dispersants help suspend and disperse contaminants in the oil to keep engine surfaces free of sludge and deposits. They fight the build-up of corrosive acids and are most efficient at controlling low-temperature deposits.

Detergents help suspend and disperse contaminants in the oil to keep engine surfaces free of sludge and deposits. They are most efficient at controlling high-temperature deposits.

Extreme-Pressure Additives coat metal surfaces to help prevent close-contact components from seizing under extreme pressure. They are activated by high temperatures and high loads to react with the metal’s surface to form a sacrificial wear layer on components.

Foam Inhibitors reduce the surface tension of air bubbles and causes them to collapse.

Detergents help suspend and disperse contaminants in the oil to keep engine surfaces free of sludge and deposits. They are most efficient at controlling high-temperature deposits.

Extreme-Pressure Additives coat metal surfaces to help prevent close-contact components from seizing under extreme pressure. They are activated by high temperatures and high loads to react with the metal’s surface to form a sacrificial wear layer on components.

Foam Inhibitors reduce the surface tension of air bubbles and causes them to collapse.

Can synthetic oil be used in new engines?

Answer: Yes. Synthetic oil is perfectly safe for use in both new and high-mileage engines.

Must new cars be broken in using petroleum oil?

Answer: No. AMSOIL synthetic motor oils can be safely used during break-in. In fact, many vehicles, including the Dodge Viper and Chevrolet Corvette, are factory-filled with synthetic oil.

Why is there an hours limit in addition to time and mileage limits on AMSOIL synthetic motor oil’s service life?

Answer: No matter how well motor oil is formulated, it won’t last forever. As the miles accumulate, motor oil begins to degrade and lose its lubricating effectiveness, while the additives are depleted. Severe-service driving conditions accelerate this process. Even with little mileage on the oil, oxidation, gases and moisture take their toll and start the degradation process, making it necessary to set both a mileage and time limit with oil change intervals. Excessive idling, common with fleet vehicles, puts additional stress on the oil, making it necessary to set an hours limit for vehicles subjected to excessive idling. Motor oil and vehicle manufacturers have developed general recommendations for the maximum amount of time or miles that the oil can be used; typically these intervals fall between 3,000 and 7,500 miles, depending on the type of service.

Many AMSOIL synthetic motor oils are specially formulated for extended drain intervals, providing maximum protection longer than other oils. Check the product data sheet for specific recommendations.

Will synthetic motor oils cause engines to leak oil?

Answer: No. Synthetic oils do not cause engines to leak oil. In fact, AMSOIL synthetic motor oil is fully compatible with modern seal materials and is properly formulated to condition seals, keeping them pliable to prevent leakage.

Can AMSOIL motor oils be mixed with other brands?

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

What kind of base stocks does AMSOIL use? Are AMSOIL synthetic lubricants PAO-based?

Answer: AMSOIL maintains formulation details as proprietary and does not divulge specifics regarding the type of synthetic base stocks used in its synthetic lubricants. AMSOIL developed the world’s first API-qualified synthetic motor oil in 1972 and has remained the leader in the synthetic lubricant industry by continually researching new technologies and demanding only the highest-quality raw materials. As the company moves forward with new technologies it is increasingly more important that this information remains proprietary. AMSOIL views synthetic base oils the same as it views additives, with each having its own set of unique properties. AMSOIL does not insist on a particular type of base stock, but insists on particular performance parameters. AMSOIL chooses whichever synthetic base stock or combination of base stocks delivers the desired result and tailors its lubricants to be application-specific (gasoline, diesel, racing, transmission, gear, extended drain, extreme temperatures, etc.). At the end of the day, the type of base stock used to formulate the oil is inconsequential; the product’s performance is what matters.

Why are AMSOIL synthetic motor oils capable of extended drain intervals?

Answer: AMSOIL synthetic motor oils are formulated using premium synthetic base oils, and the highest-quality additives, that provide extended-drain capabilities. AMSOIL synthetic motor oils achieve greater cleaning powers, while providing better equipment protection over longer oil drain intervals. The unique synthetic formulation and robust TBN retention of AMSOIL synthetic motor oils work to resist oxidation and neutralize the acids that shorten the service lives of other oils. Their characteristic resistance to high-temperature volatility (burn-off) helps reduce oil consumption, while maintaining viscosity over longer periods of time than other oils. Check the product data sheet for specific recommendations.

Will AMSOIL motor oils decrease oil consumption?

Answer: AMSOIL synthetic motor oils can reduce oil consumption in mechanically sound engines. However, AMSOIL synthetic motor oils cannot fix engines that consume oil due to mechanical problems.

Is there a recommended procedure for changing to AMSOIL synthetic motor oil?

Answer: There are no special requirements for changing to AMSOIL synthetic motor oil. However, in older vehicles with high mileage, it may be advisable to use AMSOIL Engine and Transmission Flush first. This will ensure the engine is clean and free of accumulated contaminants that may affect the service life of AMSOIL synthetic motor oil. Installation of an AMSOIL Ea Oil Filter at every oil change is also recommended.

How do AMSOIL synthetic motor oils compare to other motor oils?
What are “normal” and “severe” driving conditions?

Answer: Each vehicle manufacturer defines “normal” and “severe” driving conditions for its equipment; AMSOIL recommends owners check these definitions in their owner’s manual to determine the service condition in which they typically drive.

AMSOIL defines normal service as personal vehicles frequently traveling greater than 10 miles (16 km) at a time and not operating under severe service.

AMSOIL defines severe service for gasoline engines as turbo/supercharged engines, commercial or fleet vehicles, excessive idling, first-time use of AMSOIL synthetic motor oil in vehicles with over 100,000 miles without prior continuous use of AMSOIL synthetic motor oil, daily short-trip driving less than 10 miles (16 km), frequent towing, plowing, hauling or dusty-condition driving.

AMSOIL defines severe service for diesel engines as extensive engine idling, daily short-trip driving less than 10 miles (16km) or frequent dusty-condition driving.

See the AMSOIL Product Recommendation and Drain Interval Chart for additional information.

I am considering replacing the petroleum oil with AMSOIL synthetic motor oil in an engine that has 50,000 miles on it. I have heard that synthetics might clean the engine and cause plugging of the oil filter and passageways. Is this true?

Answer: Absolutely not. Switching from petroleum oil to AMSOIL synthetic motor oil in routinely maintained vehicles will not cause clogged oil filters or passageways, regardless of mileage. Sludge, which is caused by poor-quality oil and neglected maintenance practices, would have to be present in significant amounts to plug oil filters and passageways. If an excessive amount of sludge is present in an engine, it is just a matter of time before oil filters and passageways clog, regardless of the installation of AMSOIL synthetic motor oil.

Motor Oil: Gasoline Auto and Light Truck

Are synthetic AMSOIL motor oils “all-season” oils?

Answer: Yes. Because AMSOIL synthetic motor oils are formulated with premium synthetic base oils, they provide superior high and low-temperature performance. Synthetic oils resist thinning out at high temperatures to maintain critical protection in extreme heat. They also minimize sludge and deposit formation in high-temperature operation. AMSOIL synthetic motor oils resist thickening in cold temperatures to provide rapid cold starts and improved low-temperature operation compared to conventional oils.

Why are there multiple oils of the same viscosity?
What are the differences between AMSOIL OE Synthetic Motor Oil, XL Synthetic Motor Oil and Signature Series Synthetic Motor Oil?

Answer: AMSOIL OE Synthetic Motor Oil is recommended for vehicle manufacturer-recommended oil change intervals; AMSOIL XL Synthetic Motor Oil is recommended for extended drain intervals of 10,000 miles or six months (whichever comes first) and AMSOIL Signature Series Synthetic Motor Oil is recommended for extended drain intervals of 25,000 miles or one year (whichever comes first). AMSOIL Signature Series Synthetic Motor Oil is formulated with better base oils and more robust additives, allowing longer extended drains than AMSOIL OE or XL Synthetic Motor Oils.

Why isn’t AMSOIL Dominator® Synthetic Racing Oil recommended for street-driven vehicles?

Answer: AMSOIL Dominator Synthetic Racing Oil is a premium-quality oil formulated for maximum protection in high-performance and racing applications. It is fortified with high levels of zinc and phosphorus, which are incompatible with catalytic converters common in today’s street-driven vehicles; therefore, Dominator Racing Oil does not carry API service classifications required by many standard passenger vehicles. However, Dominator Racing Oil is the ideal recommendation for street rods, muscle cars and other high-performance vehicles driven on the street.

What does the “W” represent in 5W-30 motor oil?

Answer: The “W” in 5W-30 motor oil stands for “winter” and indicates the oil meets or exceeds certain criteria for good low-temperature performance. Motor oil with SAE viscosity grade 5W-30 behaves like an SAE 30 oil at high temperatures and SAE 5W oil at low temperatures, providing the necessary fluidity for rapid starts and efficient engine operation at low temperatures.

What is considered “normal” oil consumption?
Answer: What may be considered normal oil consumption for one vehicle may be excessive for another. As a rule, the more miles and wear accumulated on an engine, the more oil that engine consumes. Typically, one quart of oil within 3,000 miles is normal, but it is best to confirm oil consumption limits with the vehicle manufacturer. The following document explains mechanical-related issues that can lead to oil consumption: Engine Oil Consumption

Motor Oil: Heavy Duty & Off-Road Diesel

Is it safe to use Engine and Transmission Flush in diesel engines?

Answer: Yes. AMSOIL Engine and Transmission Flush helps restore operating efficiency, increase fuel economy and reduce emissions in both gasoline and diesel engines and automatic transmissions. Its potent, detergent-based formula dissolves and disperses sludge, varnish and deposits, promoting lower operating temperatures and reduced oil consumption.

Can diesel oils be used in gasoline engines?

Answer: It depends; some AMSOIL synthetic diesel oils carry gasoline specifications. Check the product data bulletin for specific product and drain interval recommendations.

Can I switch from API CJ-4 or CI-4+ diesel oil to API CK-4 diesel oil?

Answer: Yes, CK-4 oils are backward-compatible, meaning they can be used in older diesel engines. CK-4 oils are designed as direct replacements for prior-generation oils, including CJ-4 and CI-4+ oils.

Why are API FA-4 diesel oils not backward-compatible?

Answer: FA-4 oils feature lower viscosity grades and are designed to help next-generation diesel engines maximize fuel economy without sacrificing engine protection. These oils have limited backward-compatibility because some older engines were not designed to operate with lower viscosity grades. It’s up to each engine OEM to determine if FA-4 oils can be used in its engines. Check the owner’s manual or with the OEM for specific recommendations.

Does AMSOIL offer diesel oils for equipment calling for the API CJ-4 specification?

Answer: Yes. AMSOIL Premium 5W-40 Synthetic Diesel Oil, Premium 15W-40 Synthetic Diesel Oil, OE 15W-40 Synthetic Diesel Oil and OE 10W-30 Synthetic Diesel Oil are recommended for diesel applications calling for the API CJ-4 specification.

Are the AMSOIL CJ-4 diesel oils okay to use in older diesel engines?

Answer: Yes. AMSOIL Premium 5W-40 Synthetic Diesel Oil, Premium 15W-40 Synthetic Diesel Oil, OE 15W-40 Synthetic Diesel Oil and OE 10W-30 Synthetic Diesel Oil are formulated with lower sulfur content to be compatible with 2007 and later high-speed, four-stroke diesel engines with exhaust aftertreatment systems, and they also exceed previous diesel oil specifications. They are suitable for use in older diesel engines calling for API CI-4 Plus, CI-4, CH-4, CG-4 and CF-4 oils.

What is the difference between AMSOIL 5W-40 and 15W-40 diesel oil?

Answer: AMSOIL 5W-40 and 15W-40 diesel oils are multi-grade oils, meaning they provide good performance in high and low temperatures. AMSOIL 5W-40 and 15W-40 both behave like SAE 40 oils in high temperatures; however, the 5W-40 is thinner than the 15W-40 at cold temperatures.

Can CI-4 rated oil be used in 2007 or newer diesel engines?

Answer: No, we do not recommend this. Model 2007 and newer diesel engines are fitted with exhaust aftertreatment systems necessary to meet current minimum emissions requirements. API CI-4 and CI-4+ oils typically contain too much sulfated ash to be compatible with these aftertreatment systems. When in doubt, check the oil specification to determine the suitability of the oil for the intended application. We recommend using an oil meeting the manufacturer-specified diesel oil specification.

Motor Oil: Powersports and Small Engine

What are the actual oil weights for AMSOIL Shock Therapy Light and Shock Therapy Medium Suspension Fluids?

Answer: AMSOIL Shock Therapy Light Suspension Fluid corresponds to a 5 wt. and Shock Therapy Medium Suspension Fluid corresponds to a 10 wt. eo.

Is it safe to use 10W-30 in a small engine that calls for SAE 30 petroleum motor oil?

Answer: Yes. During operation the 10W-30 motor oil will perform like SAE 30 motor oil, and it is safe to use in an application requiring straight SAE 30 oil. If starting the small engine in temperatures below 50°F, the multi-grade oil may improve starting.

Can AMSOIL Formula 4-Stroke® 0W-40 Synthetic Motor Oil be used in new four-stroke snowmobiles?

Answer: Yes. AMSOIL Formula 4-Stroke Power Sports Synthetic Motor Oil is specifically formulated for use in small, hard-working four-stroke engines and is ideal for four-stroke snowmobiles and ATVs.

Can AMSOIL Signature Series 0W-30 Synthetic Motor Oil be used in lawnmower applications?
Is it okay to break in new two-cycle equipment using AMSOIL synthetic motor oils?

Answer: Yes. There are no problems using AMSOIL synthetic 2-stroke oils for break-in periods.

What does “wet clutch” mean when discussing power sports equipment?

Answer: 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.

Does AMSOIL have a two-stroke oil recommended for power valves?

AMSOIL INTERCEPTOR® Synthetic 2-Stroke Oil is recommended for power valve applications. It provides optimal detergency to keep power valves clean and superior anti-wear protection.

Will using 100:1 mix ratios with AMSOIL Saber Professional or Saber Outboard Synthetic 2-Cycle Oil void warranties?

Answer: Using AMSOIL Saber Professional or Saber Outboard at 100:1 mix ratios, where 50:1 is recommended by the manufacturer, will not void warranties. For more information, contact AMSOIL Technical Services at (715) 399-TECH (8324) or tech@amsoil.com.

Can AMSOIL Formula 4-Stroke® 0W-40 Power Sports Synthetic Motor Oil be used in a four-stroke ATV or snowmobile where the recommended viscosity is 5W-50?

Answer: Because it is an extremely shear-stable product, AMSOIL Formula 4-Stroke Power Sports Synthetic Motor Oil can be used in place of SAE 50 oil in some cases. Contact AMSOIL Technical Services at (715) 399-TECH (8324) or tech@amsoil.com for specific product interchange information.

I have had some retailers tell me that AMSOIL Saber Professional 100:1 Pre-Mix Synthetic 2-Cycle Oil will carbon valves and make them stick. I started out using it at 80:1 and have had trouble starting chain saws and weed whackers. An Echo dealer told me not to use AMSOIL or my warranty would be void. Do I need to reset the carburetor setting? As it is now, the saw floods out and won’t start until I turn it upside down and let it stand overnight. My Mac saws call for 40:1 and Echo calls for 50:1 mix ratios. Where do I go from here?

Answer:There should be no need to adjust the carburetor when using AMSOIL Saber Professional, and its use in these applications does not void the manufacturer warranty. It sounds like too much oil is being mixed with the gasoline, loading up the engines. Saber Professional is recommended for 100:1 mix ratios, ensuring good performance and helping prevent exhaust valve sticking.

Motor Oil: Motorcycles

What AMSOIL motor oils are recommended for Harley-Davidson motorcycles?

Answer: AMSOIL 20W-50 Synthetic Motorcycle Oil and SAE 60 Synthetic Motorcycle Oil are the most commonly recommended oils for Harley-Davidson applications. Check the AMSOIL Motorcycle Product Lookup for specific recommendations.

What are the recommended AMSOIL transmission and primary chaincase lubricants for a Harley-Davidson Big Twin?

Answer: For the newer Big Twins, AMSOIL recommends 20W- 50 Synthetic Motorcycle Oil (MCV) in the engine, transmission and primary chaincase. As secondary recommendations, Synthetic V-Twin Transmission Fluid (MVT) may be used in the transmission, and Synthetic V-Twin Primary Fluid (MVP) may be used in the primary chaincase. In older Harleys such as Knuckleheads, Panheads and Shovelheads, AMSOIL recommends SAE 60 Synthetic Motorcycle Oil (MCS).

What is the recommended AMSOIL transmission and primary chaincase lubricant for a Harley-Davidson Sportster?

Answer: AMSOIL recommends 20W-50 Synthetic Motorcycle Oil (MCV) for Harley-Davidson Sportster engines, transmissions and primary chaincases.

Are AMSOIL synthetic motorcycle oils wet-clutch compatible?

Answer: Yes. AMSOIL synthetic motorcycle oils meet JASO MA2 friction requirements for use in wet-clutch applications.

How can AMSOIL recommend 20W-50 Synthetic Motorcycle Oil for use in the primary chaincases and transmissions of certain motorcycles?

Answer: AMSOIL 20W-50 Synthetic Motorcycle Oil is engineered with premium additive packages specifically designed to provide high performance in motorcycle engines, transmissions and primary chaincases. However, if a customer does not want to use it in all three sumps, AMSOIL Synthetic V-Twin Transmission Fluid (MVT) and Synthetic V-Twin Primary Fluid (MVP) are secondary recommendations.

What is the recommended AMSOIL lubricant for Victory and 2013 and newer Indian motorcycles?
Answer: AMSOIL recommends 20W-40 Synthetic V-Twin Motorcycle Oil (MVI) for all Victory and 2013 and newer Indian motorcycles, excluding the Scout (which requires 15W-60 engine oil).

What is the oil change interval for AMSOIL synthetic motorcycle oils?
Are AMSOIL synthetic motorcycle oils different from AMSOIL synthetic automotive oils?
Why does AMSOIL offer more than one viscosity motorcycle oil?

Answer: AMSOIL offers motorcycle oils in different viscosities to accommodate the differences between motorcycle models and manufacturers. Just as in automotive applications, motorcycle engines require specific oil viscosities for optimal performance and protection based on the components and tolerances in the engine. Check the AMSOIL Motorcycle Product Lookup for specific recommendations.

Transmission Fluids

What are the change intervals for AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid and AMSOIL Fuel Efficient Synthetic Automatic Transmission Fluid?

Answer: When using AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid or AMSOIL Fuel Efficient Synthetic Automatic Transmission Fluid it is recommended you follow your vehicle manufacturer’s normal-service drain interval and double the recommended drain interval during conditions of severe-service. Check the AMSOIL Online Product Application Guide for detailed recommendations.

Is it required that all of the transmission fluid be removed before adding AMSOIL synthetic transmission fluid?

Answer: No. AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid and Fuel Efficient Synthetic Automatic Transmission Fluid are compatible with petroleum and synthetic transmission fluids and can be used to top-off transmission fluid levels. However, when conducting a transmission fluid change, most of the fluid in the automatic transmission will be replaced with the new fluid.

Can AMSOIL Engine and Transmission Flush be used in all transmissions?

Answer: AMSOIL Engine and Transmission Flush is recommended for use in automatic transmissions to promote efficient operation and fuel efficiency. It is not recommended for manual transmissions, CVT transmissions or differentials. AMSOIL recommends the transmission filter be changed when performing a flush.

Does AMSOIL offer transmission fluid for manual transmissions? If so, what is the change interval?

Answer: AMSOIL offers two manual transmission fluids: Synthetic Synchromesh Transmission Fluid and Synthetic Manual Transmission and Transaxle Gear Lube.

Synthetic Synchromesh Transmission Fluid is recommended for use up to 50,000 miles, or longer (up to 150,000 miles) as indicated in the owner’s manual. Synthetic Manual Transmission and Transaxle Gear Lube is engineered to last two times longer than conventional petroleum GL-4 gear oils. Following equipment manufacturer drain intervals for synthetic oils is recommended. Check the AMSOIL Online Product Application Guide for specific recommendations.

Is AMSOIL Engine and Transmission Flush compatible with seals?
Answer: Yes. AMSOIL Engine and Transmission Flush is compatible with engine and transmission seal materials. It is specially formulated to condition seals to help prevent leaks and extend seal life.

Is AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid safe to use in Mercon® V and Mercon® applications?

Answer: Yes. AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid is engineered to provide maximum performance and protection in a number of automatic transmission applications. It is formulated for Mercon V applications and is backward compatible, meaning it is also suitable for Mercon applications.

Can an “off-the-shelf,” singularly specified Ford Mercon® transmission fluid be used in a Mercon® V application?

Answer: No. The Mercon specification precedes the Mercon V specification; therefore, it is not formulated to adequately protect and perform in Mercon V applications. AMSOIL Multi-Vehicle Synthetic Automatic Transmission Fluid is engineered to exceed Mercon V and Mercon specifications and can be used in both applications.

AMSOIL Torque-Drive® Synthetic Automatic Transmission Fluid is engineered to meet the Mercon specification and is not recommended for Mercon V applications.

Oil Filtration

What is the difference between a “micron rating” and “beta ratio test” when referring to filters?

Answer: A filter’s micron rating refers to the smallest size contaminant the filter media can remove; however, there is no correlation between micron rating and a filter’s efficiency percentage.

The beta ratio test measures a filter’s efficiency for removing particles of a certain size by comparing the amount of contaminant particles before and after filtration. The number of particles after filtration is divided by the number before filtration. The resulting number is the beta ratio. AMSOIL Ea filters have a minimum beta ratio of 75, meaning they are capable of removing 98.7% of contaminant particles of a stated size.

Is it okay to use non-AMSOIL brand filters with AMSOIL lubricants?

Answer: Yes. In gasoline applications, change the non-AMSOIL brand filter at 6 months/10,000 miles, whichever comes first, when using AMSOIL XL or Signature Series Motor Oil. In diesel applications, follow the OEM filter change interval.

What is the proper change interval for Ea® Bypass Filters?

Answer: Ea Bypass Filters offer long service life. Do not exceed the limits listed in the chart below.

EaBP90 EaBP100 EaBP110 EaBP120
Mileage 60,000 70,000 80,000 120,000
Hours 600 800 1,200 1,800
Time 2 years 2 years 2 years 1 year

Can a larger size filter be used in place of what a vehicle calls for?

Answer: No. Filter recommendations by AMSOIL are based on specific equipment manufacturer requirements. Using a filter in an application it is not recommended for will void the filter’s limited AMSOIL warranty.

How long can oil drains be extended when using a bypass filtration system?

Answer: AMSOIL Bypass Filters are designed to filter out fine particles; they are not meant to extend oil change intervals beyond original recommendations. However, when fine particles are filtered out of the motor oil, it may be possible to attain longer drain intervals. This should be determined by used oil analysis. In addition, the use of an AMSOIL bypass system may allow for the use of larger oil filters, which can increase filtering capacity.

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

Answer: When used in conjunction with an AMSOIL extended-drain motor oil, Ea 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 motor oil other than AMSOIL is used, AMSOIL Ea Oil Filters must be changed according to the vehicle manufacturer’s recommendations.

Fuel Additives: Gasoline

How often should AMSOIL Gasoline Stabilizer be used in powersports and small engine equipment?

Answer: AMSOIL Gasoline Stabilizer (AST) should be used when fuel is stored for long-term, seasonal storage. For short- to medium-term storage, AMSOIL Quickshot® (AQS) is recommended.

Can multiple AMSOIL gasoline fuel additives be mixed together with gasoline?

Answer: Yes. AMSOIL fuel additives are compatible. When selecting a fuel additive be sure that it is the appropriate choice for the application. For specific product recommendations, contact AMSOIL Technical Services:

What exactly does AMSOIL P.i.® gasoline fuel additive do?

Answer: For optimum fuel efficiency and lower emissions, fuel must first be atomized into a fine mist prior to entering the combustion chamber. Over time, injector deposits produce irregular spray patterns with heavy streams of gasoline that reduce performance, while intake valve deposits also decrease efficiency. AMSOIL P.i. (API) is a potent gasoline additive designed to clean combustion chamber deposits, intake valve deposits and port fuel injector deposits to improve fuel efficiency up to 5.7 percent and an average of 2.3 percent.

Does AMSOIL offer any fuel additives that combat ethanol-related problems?

Answer: Yes. AMSOIL Quickshot® (AQS) contains a revolutionary technology that focuses on three major fuel-related issues plaguing small engines and powersports equipment: ethanol, water and dirty pump gas.

Ethanol in fuel has a tendency to absorb water and separate from the gasoline. It then sinks to the bottom of the gas tank, where it quickly degrades and creates gum, varnish and other insoluble debris that can plug fuel flow passages and negatively affect engine performance. When this ethanol/water mixture is pulled into the engine, it creates a lean-burn situation that increases combustion chamber temperatures and can lead to engine damage. AMSOIL Quickshot is proven to successfully fight ethanol problems and improve operation.

Fuel Additives: Diesel

Does AMSOIL Diesel Injector Clean comply with ultra-low-sulfur diesel (ULSD) fuel requirements?

Answer: Yes. AMSOIL Diesel Injector Clean (ADF), Cetane Boost (ACB), Diesel Cold Flow (ACF), Diesel Injector Clean + Cold Flow (DFC) and Diesel Recovery Emergency Fuel Treatment (DRC) are compliant with the federal requirements for ULSD.

Does AMSOIL Diesel Cold Flow work if diesel fuel is beginning to gel?

Answer: AMSOIL Diesel Cold Flow (ACF) is designed to prevent fuel from gelling and clogging fuel lines and filters. If the fuel is beginning to gel, the fuel should be treated with AMSOIL Diesel Recovery Emergency Fuel Treatment (DRC). Diesel Recovery disperses the wax crystals and allows the fuel to flow.

Is it safe to use AMSOIL Engine and Transmission Flush in diesel trucks and cars?

Answer: Yes. AMSOIL Engine and Transmission Flush (FLSH) is safe for use in diesel and gasoline engines and automatic transmissions to help restore equipment efficiency and operation. AMSOIL Engine and Transmission Flush is not recommended for manual transmission, CVT transmissions, differentials, transaxles, small engines or power sports equipment.

What benefits are seen when using AMSOIL Cetane Boost?

Answer: Elevated cetane levels, generally above 50, are preferable to get the most performance and power out of diesel engines. AMSOIL Cetane Boost (ACB) is engineered to improve the cetane value of diesel fuel up to seven points. AMSOIL Cetane Boost is appropriate for all types of service, including heavy- and light-duty service, on- and off- road and marine diesel engines. Cetane Boost is compatible with biodiesel and all types of exhaust emissions systems and is excellent for use with Ultra Low Sulfur Diesel Fuel (ULSD). AMSOIL Cetane Boost also improves operating cost by improving fuel economy, provides complete combustion for better power, reduces white smoke and emissions, and improves cold temperature starting.

Vehicle Warranty and AMSOIL

Does AMSOIL have a warranty for products?

Answer: Yes. AMSOIL provides a limited warranty on all AMSOIL lubricants and filters.

Will extending oil change intervals void new vehicle warranties?

Answer: No. Extending oil change intervals will not void new vehicle warranties. To affect the vehicle warranty, it must be determined that the lubricant was directly responsible for the failure; if the oil didn’t cause the problem, the warranty cannot be voided, regardless of brand or length of time in use.

How does using AMSOIL synthetic motor oil affect new vehicle warranties?

Answer: Using AMSOIL synthetic motor oil has no affect on vehicle warranties. A federal law called the Magnuson-Moss Act (1975) prevents original equipment manufacturers from putting conditions on vehicle warranties attached to any product or service identified by brand, trade or corporate name, unless the manufacturer provides that product or service free of charge. This means consumers have the freedom to use aftermarket products of their choice without fear of losing the original limited or implied vehicle warranty. For additional information, contact the AMSOIL Technical Department at

Where should questions, regarding warranty, be directed?

Answer: Call the AMSOIL Technical Department at (715) 399-TECH (8324) with questions or issues regarding warranties.


Is there a glossary of common lubricant terms used in technical bulletins?

Glossary of Acronyms and Common Terms

Can AMSOIL products be stored in cold temperatures?

Because cold-temperature storage can be detrimental to the performance of some AMSOIL products, AMSOIL offers the following storage recommendations:

Lubricants: Store at temperatures at least 10°F above the lubricant’s pour point.

Greases: Store in a dry environment at temperatures above freezing (32°F).

Gasoline Additives, Engine and Transmission Flush: No adverse issues with cold-temperature storage.

Diesel Injector Clean, Diesel Cetane Boost, Diesel Recovery: No adverse issues with cold-temperature storage.

Diesel Cold Flow, Diesel Injector Clean + Cold Flow: Store at temperatures above 0°F.

Brake Fluids: Do not store at temperatures below -40°F for longer than two weeks.

Heavy Duty Metal Protector, Metal Protector, Power Foam, Fogging Oil, Silicone Spray, Spray Grease, Heavy-Duty Degreaser: No adverse issues with cold-temperature storage as long as products are allowed to warm to room temperature before use.

Miracle Wash®: Store at temperatures above freezing (32°F).

Antifreeze and Engine Coolant: Will not freeze. No adverse issues with cold-temperature storage.

Coolant Boost: Store above 32°F.

Slip Lock®: No adverse issues with cold-temperature storage. If product separates, heat to room temperature and shake well before use.

I see AMSOIL is registered to the ISO 9001:2008 standard and the ISO 14001:2004 standard. What does each mean and what are the differences?

Answer: ISO International Standards ensure that products and services are safe, reliable and of good quality. For business, they are strategic tools that reduce costs by minimizing waste and errors and increasing productivity. They help companies access new markets, level the playing field for developing countries and facilitate free and fair global trade.

ISO 9001:2008 is the most widely used quality standard throughout the world for quality management systems. It is based on the eight quality management principles: customer focus; leadership; involvement of people; process approach; system approach to management; continual improvement and fact-based decision making; and mutually beneficial supplier relationships. When fully adopted, these principles have been proven to enhance organizational performance in providing quality products and services to customers. For customers and potential industry partners, ISO 9001:2008 certification provides assurance that AMSOIL has systems in place to ensure consistent product quality on every production run.

ISO 14001:2004 sets out the criteria for an environmental management system. It does not state requirements for environmental performance, but maps out a framework that a company or organization can follow to set up an effective environmental management system. ISO 14001:2004 certification indicates that AMSOIL takes environmental stewardship seriously and takes deliberate steps to minimizing the company’s environmental impact.

Because its Quality Management and Environmental Management Systems are registered to ISO standards, AMSOIL Dealers and customers can be assured that AMSOIL not only manufacturers high-quality products, but that the company is also actively monitoring and reducing its environmental impact.

Where can AMSOIL product recommendations, for equipment, be found?

Answer: AMSOIL provides a number of product lookup and filter lookup guides to help determine the appropriate lubricant or filter for an application. These lookup guides are found on the top  navigation menu. The following lookup guides are available to determine proper recommendations: Auto and Light Truck, Power Sports, Small Engine,  Vintage Vehicle and Heavy Duty.

Oil Analysis

Does AMSOIL provide oil analysis services?

Answer: Yes. AMSOIL provides oil analysis services through Oil Analyzers Inc

What is oil analysis?

Answer: Oil analysis is a process for determining the chemical properties of a lubricant. It’s often used to detect mechanical issues before major failures occur. Used oil samples are analyzed for specific physical properties, contaminant levels and wear debris from the equipment to determine if the oil can remain in service. Oil analysis can also monitor the wear rate of the equipment and detect if wear is elevated beyond acceptable limits. It is often used as part of a preventative maintenance program.

Why should oil analysis be done?

Answer: As part of a preventative maintenance program, oil analysis can help owners and operators be proactive in their maintenance practices to help increase equipment productivity and eliminate costly downtime. The cost of routine oil analysis far outweighs the costs to replace major equipment on large industrial equipment, commercial and passenger car vehicles.

For those reluctant to extended oil intervals, oil analysis provides evidence that AMSOIL motor oils have exception performance and protection capabilities in extended service.

Maintenance Products

Is AMSOIL Antifreeze and Engine Coolant silicate and borate free?

Answer: Yes. AMSOIL Antifreeze and Engine Coolant (ANT) contains proprietary poly-organic acid technology that is silicate and borate free.

Is AMSOIL Propylene Glycol Antifreeze and Engine Coolant compatible with aluminum intakes, cylinder heads and engine blocks?

Answer: Yes. AMSOIL Antifreeze and Engine Coolant (ANT) is compatible with all engine and cooling system components. It surpasses all ASTM standards for metallic corrosion to protect metals and provide uncompromised cooling protection.

Does AMSOIL recommend a particular type of water when mixing AMSOIL Antifreeze and Engine Coolant?

Answer: AMSOIL recommends deionized or distilled water when mixing with AMSOIL Antifreeze and Engine Coolant (ANT). Using deionized or distilled water prevents adding harmful contaminants that can negatively affect the antifreeze product and cooling system equipment.

Gear Oils

Will GL-2 through GL-5 gear lubes hurt synchronizers?

Answer: No. All gear oils AMSOIL recommends for manual transmission applications are perfectly safe for synchronizer materials.

Does AMSOIL Slip Lock need to be used with AMSOIL gear lubricants?

Answer: AMSOIL automotive gear lubricants have excellent frictional properties and generally will not need to be fortified with additives. If on rare occasions differential chatter occurs, AMSOIL Slip Lock is recommended.

Can different AMSOIL gear lubricant viscosities be mixed?
Answer: AMSOIL gear lubricants are compatible with one another. Mixing different AMSOIL gear lubricants, however, could change the viscosity properties of the oils, depending on the ratios and viscosities mixed. This could impact the drain interval. Mixing different viscosities of lubricants should be minimized whenever possible.
If a vehicle manufacturer recommends a 75W-90 gear lube, may a 75W-140 be used?

Answer: No. In most cases, 75W-140 gear lube is too thick to be used in place of 75W-90. For modified or non-stock differentials where a higher viscosity gear lube may be desired, AMSOIL typically recommends 75W-110. Contact AMSOIL Technical Services for specific recommendations

Are AMSOIL gear lubes safe for yellow metals?

Answer: Yes. As long as temperatures don’t exceed 250°F (121°C), all AMSOIL automotive gear oils are safe to use in drive train applications with yellow metals. Check the AMSOIL on-line look-up guide at www.amsoil.com for specific questions.

Is AMSOIL gear lube compatible with RTV sealant?

Answer: AMSOIL automotive gear lubricants are compatible with RTV sealant. It is very important the RTV sealant manufacturer’s instructions be followed and the product be FULLY cured before contact with the gear lubricant.

Can AMSOIL Severe Gear® be used in Harley-Davidson transmissions?

Answer: Yes. In Evolution 1340 and all Twin Cam Harley-Davidsons, AMSOIL recommends AMSOIL 20W-50 Synthetic Motorcycle Oil (MCV) or Severe Gear 75W-110 Synthetic EP Gear Lube (SVT). In older Harleys, such as Knuckleheads, Panheads and Shovelheads, AMSOIL Synthetic SAE 60 Motorcycle Oil (MCS) or Severe Gear 75W-140 Synthetic EP Gear Lube (SVO) is recommended.

Is AMSOIL gear lube compatible with conventional gear lubricants?

Answer: AMSOIL automotive gear lubricants are compatible with other synthetic and petroleum based gear lubricants. However, mixing AMSOIL gear oils with oils will shorten the life expectancy and reduce performance benefits.

API Licensing

What is API licensing for passenger cars?

Answer: An API (American Petroleum Institute) license indicates that a specific motor oil formulation has passed the minimum performance standards as defined by a series of laboratory bench, physical, chemical and engine tests. These tests and minimum performance standards are determined by the API Lubricants Committee to address specific areas such as engine wear, deposits, fuel economy and emissions. The committee is comprised of representatives from automobile, oil and additive companies.

Which companies license formulas with the API?

Answer: Additive companies develop licensed formulas that they offer to oil companies to re-license. It is inexpensive to re-license one of these formulas, and the majority of oil companies choose to do this to avoid the costs associated with testing their own formulas. This lowers the value of such engine oils because the same chemistry is being sold under many brand names. The lubricant formulas from AMSOIL INC. are unique and proprietary.

Is there any flexibility in manufacturing an API-licensed formula?

Answer: API licensing was originally developed for mineral-based oils, and it affords these oils more flexibility than synthetic oils. Conventional oils comprised of petroleum base stocks may use a simple program called base stock interchange for added flexibility in manufacturing and purchasing. Interchange means that by completing the proper paperwork and running a few minor tests an oil company can choose to buy these petroleum base stocks from many different suppliers. This ensures adequate supply and competitive pricing. However, synthetic base stocks are supplier specific and base stock interchange is not allowed. For example, if a formula was tested with an ester base stock from a specific supplier then only that supplier’s ester can be used. Complete engine testing would be required to use that exact same ester from another supplier and is therefore not performed because of the associated costs. This inflexibility makes price negotiations with synthetic base stock suppliers very difficult and increases business risk. Supply disruptions from only one source could shut down production.

There is also something called viscosity grade read-across. Fortunately, this applies to both petroleum and synthetic base stocks, although the better cold-temperature performance of synthetics makes it more difficult to achieve in some situations. The read-across guidelines ensure that if a manufacturer properly formulates the lubricant for which all of the API tests have been performed, then the manufacturer may use that same basic formula to make more grades (i.e. 5W-20, 5W-30, 10W-30, etc.) of the same motor oil.

Finally, there is a rule for substitutions in the Chemical Manufacturers Association (CMA) code of practice that allows a small degree of flexibility for all formulas. It allows a company to make changes to certain components in the formula with limited testing and paperwork requirements, provided that the additives are at the same or higher concentration.

Why doesn’t AMSOIL license all of its synthetic motor oils?

Answer: If all AMSOIL motor oils were API licensed, the company could not source new raw materials from multiple suppliers, which would greatly increase the threat of supply disruption and the likelihood of extraordinarily high prices. To solve this problem, the API must establish base stock interchange guidelines for synthetic base stocks just as they have for other base stocks, as well as develop interchange guidelines for other components too. Furthermore, licensing formulas limits the ability to quickly adopt new technologies as they are discovered; each variation from the originally licensed formula requires re-submission for complete engine testing (see the Ask AMSOIL entry above for more information).

How does AMSOIL INC. ensure that its products meet or exceed the minimum specifications of the tests required for API licensing?

Answer: First, AMSOIL INC. works closely with major additive companies to select the top-performing, and usually most expensive, passenger car and heavy-duty diesel motor oil additives. These additives have already passed all of the API licensing requirements in a petroleum- or synthetic-based formulation. Then, AMSOIL works with the additive company to maximize the amount of additive used and to boost the additive package in selected performance areas to achieve an optimum performing additive package for the intended application. This is unlike many other oil companies that, because additives are expensive, use the minimum amount of the least expensive additives required to meet the minimum API requirements.

AMSOIL then uses a combination of synthetic base stocks with known performance characteristics as replacements for the petroleum base stocks to optimize performance in areas of lubricity, volatility, viscosity index, oxidation and nitration resistance, pour point, flash point, deposit control, soot handling, emissions and many other areas as well. AMSOIL also uses a high-quality V.I. improver with outstanding viscosity and cleanliness properties. This replaces the inexpensive, low-quality V.I. improver used in standard API-licensed petroleum formulas. AMSOIL does laboratory bench tests and runs field tests to verify the superiority of the synthetic formula. AMSOIL continues to monitor the performance of the oil through close scrutiny of tens of thousands of oil analysis tests per year across a wide variety of vehicles all around North America and the world. AMSOIL INC. has been collecting used synthetic oil samples from passenger cars since 1982. No other oil company has such a vast database of the performance of synthetic lubricants over extended drain intervals. AMSOIL products and formulations outperform API-licensed oils because they are engineered for top performance from the very beginning.