Select Synthetics

In March 2026, AMSOIL launched the Fleece Freedom Series, a line of premium diesel lubricants engineered through a close, technical partnership with Fleece Performance Engineering. Freedom Series emerged when AMSOIL INC. and Fleece Performance Engineering partnered to develop an advanced 100% synthetic diesel oil formulation for use in high-performance and racing diesel vehicles equipped with Fleece Performance products.

By combining AMSOIL's leadership in premium synthetic oil formulation with Fleece's experience and expertise in high‑performance diesel engineering, Freedom Series delivers exceptional protection and performance for turbodiesel pickups - from daily drivers to high‑output builds for racing applications.*

* Note: The Fleece Freedom Series product line is Not Currently Available in Canada !

Based in Pittsboro, Indiana, Fleece Performance Engineering manufactures everything from turbochargers to cylinder heads and long blocks, while Freedom Racing Engines operates as a completely separate division of the company. Fleece Performance Engineering is one of the most recognized names in the high-performance diesel market and boasts a solid reputation for innovation, quality and service.

“Partnering with AMSOIL allowed us to influence the lubricant design at a molecular level for the first time,” said Jeff Everett, Fleece Performance Engineering’s VP of Sales. “Freedom Series gives diesel enthusiasts and engine builders products that were created through real collaboration from industry leaders — products that are engineered to perform.”

Freedom Series represents a significant expansion of the AMSOIL diesel engine oil portfolio, combining advanced AMSOIL formulation expertise with insights from one of the diesel industry’s most performance‑driven engineering teams. The products were co‑designed through an iterative development process that merged AMSOIL diesel oil formulation prowess with real‑world insights from Fleece Performance Engineering and racing programs.

Each product in the series was developed to withstand extreme heat, heavy loads and the elevated stress common in modified and high‑performance diesel platforms. "Diesel enthusiasts and engine builders push their equipment harder than ever, and they need lubricants engineered to keep up," said Ryan Radzak, AMSOIL Product Marketing Manager. "Freedom Series reflects our continued commitment to delivering purpose‑built solutions that perform in the most demanding conditions." Treat your diesel truck right with our Fleece Freedom Series 100% Synthetic Diesel Oil.

Treat your diesel right with Freedom Series 100% Synthetic Diesel Oil. Freedom Series emerged when AMSOIL and Fleece Performance Engineering partnered to develop an advanced formulation for diesel pickup trucks equipped with Fleece products. Freedom Series Synthetic Diesel Oil provides excellent turbo cleanliness, superior soot control and outstanding wear protection. The result: protection engineered to perform.

• Advanced formulation for diesel pickup trucks equipped with Fleece Performance products.
• Provides excellent turbo cleanliness, superior soot control and outstanding wear protection.
• Delivers protection engineered to perform in demanding conditions.

Wear on rings and cylinder liners leads to increased oil consumption and loss of compression, resulting in reduced horsepower and fuel economy. Freedom Series Synthetic Diesel Oil is formulated to deliver outstanding wear protection in demanding operating conditions, maximizing the life of your diesel pickup and reducing maintenance costs and downtime.

• Protects rings and cylinder liners to reduce oil consumption and maintain compression.
• Helps maximize horsepower and fuel economy while reducing maintenance costs.
• Formulated to perform in demanding operating conditions, including towing, hauling or modifying for additional horsepower.

Soot buildup in a diesel pickup can reduce power, increase abrasion, cause emissions-system problems and decrease fuel economy. Freedom Series is naturally resistant to oxidation and the thickening effects of soot contamination. That, along with boosted detergent/dispersant additives, keeps soot particles suspended independently, helping prevent the formation of larger, wear-causing particles. Viscosity increase is minimized and soot-related wear is controlled. Lower volatility also helps Freedom Series retain its viscosity after high-temperature service for maximum engine protection and efficiency.

• Boosted detergent/dispersant additives keep soot particles suspended to prevent wear.
• Resists oxidation and thickening caused by soot contamination.
• Minimizes viscosity increase and controls soot-related wear for maximum efficiency.

Freedom Series resists thermal (heat) breakdown. Unlike conventional oils, Freedom Series contains no wax, staying fluid in sub-zero temperatures for easier starting, improved oil flow and reduced wear, making it excellent for use in both hot-operating engines and cold-weather starting extremes.

• Resists thermal breakdown for reliable performance in high-heat conditions.
• Stays fluid in sub-zero temperatures for easier starting and reduced wear.

Freedom Series has a low rate of volatility (burn-off), reducing oil consumption during operation and passing less oil vapor into the combustion chamber.

Freedom Series provides the turbo cleanliness needed to support reliability when towing, hauling or modifying for additional horsepower.

➪ For additional information, please check out our AMSOIL/Fleece Freedom Series 100% Synthetic Diesel Oil Data Bulletin (PDF).

Fleece Freedom Series 15W-50 100% Synthetic Racing Oil is designed for those who demand superior protection for their high-performance engines. It is specifically engineered to deliver the most important benefits for high-horsepower and turbocharged competition diesel engines, including superior bearing protection and robust durability that withstands extreme pressures and temperatures.

Whether competing in sled pulls, drag races or dyno challenges, competitors using Fleece Freedom Series 100% Synthetic Racing Oil enjoy confidence and security in knowing that their powerful diesel engines are receiving maximum protection and achieving maximum performance.

• Specifically engineered for high-horsepower and turbocharged competition engines.
• Delivers superior bearing protection and robust durability.
• Withstands extreme pressures and temperatures.
• Heavily fortified with zinc and phosphorus for maximum wear protection.

Racing and high-performance diesel engines are modified to deliver maximum horsepower and torque. Their powerful designs create shearing forces that can cause oils to lose viscosity, leaving bearings, pistons and other components vulnerable to wear and failure.

Fleece Freedom Series 15W-50 100% Synthetic Racing Oil effectively withstands high cylinder pressures and protects against engine wear. It is heavily fortified with zinc and phosphorus anti-wear additives (ZDDP) to provide additional protection against scuffing and wear in severe conditions.

• Effectively withstands high cylinder pressures and protects against wear.
• Heavily fortified with zinc and phosphorus anti-wear additives for extra protection against scuffing and wear.
• Withstands shearing forces, effectively protecting bearings, pistons and other components.

High-horsepower diesel engines push a lot of fuel, leading to fuel dilution of the engine oil. Fuel reduces the motor oil’s viscosity. As the oil becomes thinner, it compromises the lubrication of critical components, increasing engine wear. Fleece Freedom Series 100% Synthetic Racing Oil’s robust formulation helps offset the damaging effects of fuel dilution by maintaining its protective viscosity longer.

• Robust formulation helps offset the damaging effects of fuel dilution by maintaining its protective viscosity longer.
• Resists thinning to ensure critical components remain lubricated, reducing wear.

Over time, turbos can suffer reduced performance or even a catastrophic failure. Fleece Freedom Series 100% Synthetic Racing Oil is designed with an extremely durable 15W-50 full synthetic formulation that contains maximum levels of oxidation-inhibitor additives to resist harmful oxidation and provide exceptional resistance to deposit formation, preserving turbocharger performance and life.

• Durable synthetic formulation contains maximum levels of oxidation-inhibitor additives.
• Resists harmful oxidation and provides exceptional resistance to deposit formation.
• Preserves turbocharger performance and life.

➪ For additional information, please check out our AMSOIL/Fleece Freedom Series 15W-50 Synthetic Racing Oil Data Bulletin (PDF).

Fleece Freedom Series Break-In Oil is the preferred break-in oil of Fleece Performance Engineering and Freedom Racing Engines. It is designed to deliver maximum compression, horsepower and torque by providing quick and efficient piston ring seating in new and rebuilt high-performance and racing engines.

It is formulated with zinc and phosphorus (ZDDP) anti-wear additives to protect cam lobes, lifters and rockers during the critical break-in period when wear rates are highest. Its increased film strength also protects rods and main bearings from damage.

Fleece Performance Engineering and Freedom Racing Engines have been using this AMSOIL formulation for years. High horsepower and torque from their builds have tested the formula over and over. Freedom Series Break-In Oil is for engine builders who want to push limits without sacrificing proper break-in.

• Preferred break-in oil of Fleece Performance Engineering and Freedom Racing Engines.
• Quickly seats piston rings.
• Increased zinc and phosphorus (ZDDP) protect against wear.
• Maximizes compression and power.
• Contains no friction modifiers

The primary goal during engine break-in is to seat the rings against the cylinder wall. Properly seated rings increase compression, resulting in maximum horsepower; they reduce oil consumption and prevent hot combustion gases from entering the crankcase. To achieve this, the oil must allow the correct level of “controlled wear” to occur between the cylinder wall/ring interface while maintaining wear protection on other critical engine parts.

Insufficient break-in leaves behind peaks on the cylinder wall that prevent the rings from seating. The deeper valleys, meanwhile, allow excess oil to collect and burn during combustion, increasing oil consumption. Too much wear results in cylinder glazing due to peaks “rolling over” into the valleys and preventing oil from collecting and adequately lubricating the cylinder wall.

Freedom Series Break-In Oil’s friction-modifier-free formula allows the sharp peaks on newly honed cylinder walls (fig. 1) to partially flatten. The result produces more surface area for rings to seat against, allowing the formation of a dynamic seal that increases compression, horsepower and torque (fig. 2).

• Friction-modifier-free formula allows sharp peaks on newly honed cylinder walls to partially flatten, creating more surface area for rings to seat
• Forms a dynamic seal that increases compression, horsepower and torque.

New flat-tappet camshafts and lifters are not seasoned or broken in and must be heat-cycled to achieve proper hardness. During the break-in period, these components are susceptible to accelerated wear because they are splash lubricated, unlike other areas of the engine that are pressure lubricated.

Fleece Freedom Series SAE 30 Break-In Oil contains high levels of zinc and phosphorus (ZDDP) additives designed to provide the anti-wear protection required during this very critical engine break-in period.

• Contains high levels of zinc and phosphorus (ZDDP) additives.
• Delivers excellent protection for splash-lubricated parts, like camshafts and lifters, during break-in.

High-performance and racing engines often use aftermarket parts designed to increase torque and horsepower. This added stress can rupture the motor oil film responsible for preventing harmful metal-to-metal contact on connecting rods and main bearings. The premium base oils in Freedom Series Break-In Oil provide increased film strength to protect connecting rods and main bearings from wear.

➪ For additional information, please check out our AMSOIL/Fleece Freedom Series SAE 30 Break-In Oil Data Bulletin (PDF). _ | _ SHOP NOW