Lucas Oil vs AMSOIL: Who makes better motor oil & additives?

With my extensive experience as a lubrication specialist and former Ford Motor Company powertrain engineer, I've spent countless hours testing and analyzing engine performance and durability. This hands-on expertise has given me unique insight into the critical role that high-quality synthetic engine oils play in protecting modern engines. In this article, I'll compare Lucas Oil and AMSOIL synthetic motor oil products to help you understand which might be the better choice for your vehicle's needs.

Overview of Lucas Oil & AMSOIL

Lucas Oil and AMSOIL are both very prominent players in the synthetics industry that have a lot in common, but they also have fairly distinct histories and characteristics that set them apart from one another, especially in their company origins and development paths.

Company Origins

AMSOIL was founded in 1968 by Al Amatuzio - a former jet fighter squadron commander, in Superior, Wisconsin. His background in aviation inspired him to research, test, and develop his own synthetic oils for automotive use. Synthetics were used exclusively in jet engines at the time and he was certain synthetics would also be a great choice for the automotive industry.

Lucas Oil was established later, in 1989, by Forrest Lucas and his wife Charlotte. Lucas's background was primarily in long-haul trucking, which led him to develop oil and fuel treatments aimed at reducing mechanical failures and increasing mileage in the trucking industry.

Innovation

AMSOIL's early claim to fame was pioneering the first full synthetic motor oil to meet API service requirements (AMSOIL's 10W-40 Synthetic Motor Oil) in 1972. In the many years leading up to that breakthrough, Amatuzio had been constantly researching synthetic oils and asked one of his fellow fighter pilots to try his formulation in his own vehicle. At that time, motor oil quality was extremely poor and engines didn't last very long. Oils were constantly breaking down in high-temperature conditions and made it much more difficult for engines to start in cold weather. This breakthrough signaled a new era in lubrication science, and many big oil companies would soon follow-suit with their own full synthetic engine oils.

While Lucas Oil has made significant contributions to the industry, they're not as well-known for the same level of "firsts" as AMSOIL. However, they've developed a reputation for quality racing oils and additives, sponsoring many racing events and race teams throughout the years.

Product Applications

Both companies offer a wide range of lubricants, but with slightly differing focuses:

AMSOIL primarily specializes in full synthetic lubricants for an extremely wide range of applications, including automotive, powersports, racing, motorcycles, ATVs/UTVs, snowmobiles, heavy-duty trucks, diesels, and commercial vehicles, RV's, marine, small engines, classic/vintage vehicles, and several more industrial and commercial applications like lubricating air compressors, bearings, turbines, gearboxes, and many more.

Lucas Oil offers conventional and synthetic blends (as well as oil additives) covering a similar range of applications as AMSOIL, but with far fewer total products.

Why doesn't AMSOIL make engine oil additives?

As we'll cover below, performance testing has shown that engine oil additive products severely degrade the flow characteristics and wear-protection abilities of your oil. Especially at cold temperatures, these "oil additives" can effectively turn your engine oil into glue, especially at cold temperatures and during engine start, when your engine needs lubricated the most to prevent unnecessary wear.

When you use a high-quality engine oil that's already specially formulated with premium synthetic base oils, detergents, and additives, right in the bottle (i.e. AMSOIL), you don't need to add anything extra to ensure your vehicle experiences maximum performance and protection.

Marketing Differences

AMSOIL primarily relies on a network of independent dealers for distribution, paying commissions on sales. They also heavily market and advertise their own products and have secured many strategic partnerships with aftermarket engineering companies, racing series', and race teams, while also partnering with thousands of automotive and powersports service centers, oil change shops, and commercial businesses through their AMSOIL Installer, Retail, and Commercial Account business opportunities. AMSOIL keeps most of their products out of big-box stores to maintain a competitive advantage and to help support value-adding service business that offer specialized products and services.

Lucas Oil relies on more traditional retail distribution models, with products available in major auto parts stores and retailers like Walmart and Amazon.

Ownership

AMSOIL has been family owned and operated since their inception. Currently, the founder's son, Alan Amatuzio, serves as Chairman and CEO.

Lucas Oil is now run by Forrest Lucas's son Morgan Lucan and his wife Katie Lucas, also maintaining its status as a family-owned business.

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Lucas Oil vs AMSOIL Matchup

Both oil brands produce a wide variety of lubricants for many similar applications, so we'll be directly comparing oils of similar viscosities and additives for similar applications to see which bolster the best technical specifications and performance test results.

Arguably, Lucas Oil is probably more well-known for their fuel and oil additives than they are for their motor oils. So we'll also be comparing those as well. In this matchup, we'll analyze AMSOIL Signature Series with Lucas Oil Synthetic API SP passenger car motor oils, AMSOIL Upper Cylinder Lubricant vs. AMSOIL Upper Cylinder Lubricant and AMSOIL Performance Improver (PI) with Lucas Oil Fuel Stabilizer.

AMSOIL Signature Series vs Lucas Oil API SP

In this first matchup, we'll take the best of the best full synthetics for passenger vehicles from both brands to see how they compare across technical specifications and approvals. AMSOIL Signature Series and Lucas Oil Full Synthetic both meet or exceed similar specifications & approvals but there are notable differences.

Specifications & Approvals

API Specifications:

• Both oils meet current API SP and SN Plus standards
• Both have backward compatibility with older API specs
• Both demonstrate commitment to fuel economy through Resource Conserving designation

ILSAC Standards:

• Both oils meet current ILSAC GF-6A requirements
• AMSOIL additionally lists GF-5 and GF-4, documenting backward compatibility
• GF-6A is specifically for lower viscosity oils (0W-20, 5W-20, 0W-30, 5W-30)

OEM Approvals

• Lucas Oil: Has several key OEM approvals:
  • GM dexos1 Gen 3 (License # D335AADG273)
  • Ford WSS-M2C946-B1
  • Chrysler MS6395
• AMSOIL: Has a broader range of OEM approvals including:
  • GM dexos1 Gen 3
  • Multiple Ford WSS specifications (WSS-M2C946-B1, WSS-M2C946-A, WSS-M2C929-A, WSS-M2C961-A1)
  • Chrysler MS-6395
  • Honda HTO-06
  • European ACEA A5/B5, A1/B1 certifications

From the industry approvals outlined above, both oils meet current industry standards for modern engines and share several important OEM approvals. AMSOIL Signature Series 5W-30 demonstrates broader application capability through additional Ford specifications and European ACEA certifications. Both oils carry GM's stringent dexos1 Gen 3 specification. AMSOIL's additional European and Honda certifications suggest more extensive testing and validation across a wider range of applications.

Next we'll compare technical data provided by both manufacturers for their full synthetic 5W-30 passenger car engine oils.

Manufacturer Specified Ratings

*hover over each specification for more details.

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Lucas Oil doesn't provide many technical specifications within their data sheet for the 5W-30 Full Synthetic Oil. And, the most recent data sheet doesn't list the OEM and industry approvals that are found on their engine oil bottles. It's likely their product data sheets haven't been updated in a while to reflect their current formulations. But, from the data they do provide, Lucas shows slightly higher viscosity metrics at both test temperatures and a marginally better viscosity index, suggesting slightly better stability across temperature ranges.

Lucas also doesn't provide any cold-weather performance data like the CCS simulated cold-cranking viscosity nor the pour point. Lucas Oil's synthetic 5W-30 shows a flash point of >204°C, which is somewhat abnormal here to provide a range instead of a hard number. Assuming it is 204, it's much lower than AMSOIL's which reports 220°C, suggesting better high-temperature stability and less oil consumption throughout the life of the oil.

While Lucas shows somewhat strong performance in basic viscosity metrics, AMSOIL provides much more comprehensive technical data and a clearly defined extended drain interval of 25,000 miles. AMSOIL's transparency here is what I value the most; they don't hide any of their testing data because they know they provide a high quality product.

AMSOIL Signature Series vs Lucas Oil - Pricing

Lucas Oil doesn't indicate a recommended drain interval for their oil, so we'll assume an average OEM spec of 5,000 miles between oil changes. At the AMSOIL Preferred Customer pricing, their Signature Series 5W-30 is slightly cheaper than the Lucas Oil 5W-30.

Assuming an annual vehicle mileage of 15,000 miles, you'd need 3 oil changes using Lucas Oil versus just one running AMSOIL for the entire year. Lucas Oil would cost you almost $180 through the year just on the oil. You would save around $100 running AMSOIL through the year at retail, and save even more with their PC discount, even after accounting for the price of AMSOIL's membership.

Oil Additives?

Another major way that Lucas Oil and AMSOIL majorly differ is on the idea of oil additives. Lucas Oil makes many different types of oil additive products, from oil stabilizers, to stop leaks, to engine treatments. AMSOIL does not make oil additives, in fact, AMSOIL's position is that oil additives are unnecessary.

AMSOIL did their own testing to see how oil additives affected a base oil's cold crank viscosity and kinematic viscosity at operating temperatures. They discovered several red flags to help consumers think twice before purchasing oil additives.

It's unlikely someone using a top-shelf synthetic oil is going to augment their oil with an aftermarket additive, so they chose a name brand conventional 5W-30 motor oil that's readily available at almost any auto parts store. AMSOIL subjected the conventional motor oil to a few different industry-standard bench tests to determine wear protection, cold-flow ability and viscosity stability. After gauging the oil's baseline performance, they then treated samples of the same oil with two popular oil additives according to the treat rates specified on the labels, and then tested the oil again.

Surprisingly, the conventional oil treated with both oil additives showed improved wear protection in bench testing compared to the untreated oil. But, it came with a big tradeoff.

The oil additives impaired the oil's cold flow ability and increased the viscosity so much so, that it no longer met the viscosity requirements of a 5W or a 30-weight oil. From the graph pictured below, the orange bar shows the untreated conventional oil's performance in the Cold-Crank Simulator (CCS) Test (ASTM D5293). CCS testing is important to determine an oil's ability to flow well during cold starts, which helps to prevent dry starts and protects against wear.

The untreated oil falls within the cceptable range for a 5W oil (6,600 cP max @ -30°C is allowed). AMSOIL OE 5W-30 Synthetic Oil is also included for comparison (dark blue bar). Look at the conventional oil's performance in the CCS Test after having been treated with engine oil additives (green and light blue bars). Both the stop-leak additive and the oil stabilizer increased the oil's viscosity so much that both samples no longer meet the requirements of a 5W oil, completely failing the test.

This means the oil won't flow as readily at startup, severely impairing the oil's ability to prevent wear protection at the time when most wear occurs. It's also important to note that cold-flow isn't just important for those of us in colder climates. Cold to your engine is really any temperature below normal operating temperature, which is about 212°F (100°C). The better the oil flows after the engine has sat for an extended amount of time, the better it will protect against wear. The CCS Test is also representative of an oil's flowability at 80°F (17°C) or warmer.

Oil Additives Effect on Viscosity at Operating Temps

Now what about the oil's viscosity at normal operating temperatures? Will oil additives also impede an oil during normal operation?

Again, the engine oil additives raised more red flags. In this graph, the orange bar shows the viscosity of the untreated conventional oil at 100°C (212°F). It falls within the acceptable range for a 5W-30 oil, shown by the transparent green area.

Now look at the viscosity at 100°C (212°F) of the oil treated with the stop-leak and oil stabilizer additives. Both samples of oil now fall outside of the acceptable viscosity range, ultimately altering the oil to resemble a 40- or 50-weight oil instead of the 30-weight the engine manufacturer recommends.

For even more confirmation, watch the video below, demonstrating just how negatively impactful these oil additives are on your oils flow characteristics, especially in cold temperatures during engine startup.

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Over time, your engine will suffer from using these oil additives. They might appear to help stop an oil leak temporarily, but is a leaking seal or gasket worth ruining your entire engine? I don't think so.

The truth is, if you're using a high-quality engine oil that is already formulated with a well-balanced combination of synthetic base oils, additives and detergents, like AMSOIL, you don't need additives. And your oil will flow properly at all temperatures. If you want your motor oil to flow like glue, use an oil additive. If not, choose AMSOIL.

AMSOIL vs Lucas Oil Testing & Reviews

Several comparison ASTM tests have been done showcasing how AMSOIL and Lucas Oil stack up in side-by-side performance tests.

Cold Crank Testing

AMSOIL Signature Series 5W-30 provides better cold cranking viscosity than Royal Purple, Red Line, and Lucas Oil, helping improve wear protection for engine components at startup. Based on independent third-party testing in the industry-standard ASTM D5293 Cold Crank Simulator test as required by SAE J300.

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For the most protection during startup, especially in colder climates, AMSOIL Signature Series is the obvious choice.

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Better Rust Protection

AMSOIL Signature Series 15W-40 provides up to 2X better rust protection, compared to Mobil 1, Shell Rotella, Schaeffers & Lucas Oil. Based on industry standard testing using the NMMA FC-W Rust Test.

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Lubricity Testing - Additives

AMSOIL Upper Cylinder Lubricant delivers 18 percent more lubricity than Lucas and 20 percent more than Sea Foam for better retention of horsepower and fuel economy.

Based on independent testing of AMSOIL Upper Cylinder Lubricant, Lucas Upper Cylinder Lubricant and Sea Foam Motor Treatment obtained on 02/13/2019 using the ASTM D6079 modified for use with gasoline.

AMSOIL or Lucas Oil?

Based on our detailed comparison of AMSOIL Signature Series and Lucas Oil Synthetic 5W-30, here's what stands out:

Both oils are high-quality full synthetics that meet modern engine requirements, but there are some notable differences. When looking at specifications, both oils carry important certifications like API SP Resource Conserving and GM dexos1 Gen 3, but AMSOIL includes additional approvals like Honda HTO-06 and European ACEA certifications, suggesting broader testing and validation.

Looking at the technical data, Lucas Oil actually shows slightly higher viscosity numbers and a marginally better viscosity index. However, they don't provide several crucial specifications that AMSOIL does - like cold-weather performance data and exact flash point temperatures. This transparency from AMSOIL gives us more confidence in understanding exactly what protection they're getting.

The biggest practical difference comes down to service life. AMSOIL Signature Series is guaranteed for 25,000 miles or one year, while Lucas Oil doesn't specify a drain interval. For the average driver doing 15,000 miles annually, this means three oil changes with Lucas versus just one with AMSOIL. At Lucas's Amazon price of $11.99 per quart, you'd spend almost $180 yearly on oil alone. AMSOIL would require just one oil change for the same period, making it significantly more economical - especially with their Preferred Customer program.

Beyond the cost savings, fewer oil changes also means less time spent on maintenance, reduced environmental impact from oil disposal, and lower filter costs since you only need one instead of three. For someone looking for maximum protection with minimum maintenance requirements, AMSOIL makes a compelling case here.

For most drivers, the decision will likely come down to price & performance. For those prioritizing maximum engine protection and verified extended drain intervals with the added benefit of reduced costs, AMSOIL Signature Series is the clear choice.

And from our analysis of engine oil additives and how effective they are at quickly deteriorating the quality of your oil, as well as the performance testing of popular upper cylinder lubricants, showcasing the superior lubricity of AMSOIL UCL alongside Lucas and Sea Foam products, AMSOIL is the obvious choice for any and every application over Lucas Oil.

In my professional opinion, AMSOIL offers a better overall value. AMSOIL fuel additives also perform much better than Lucas Oil products in independent lab testing. For the protection you demand and the performance you deserve, choose AMSOIL.

Sources

• Lucas Oil Full Synthetic 5W-30 Data Sheet
• AMSOIL Signature Series 5W-30 Data Sheet