The 2018 Subaru Forester with the 2.5L FB25BA engine is built for versatility, serving owners who demand all-weather capability and everyday reliability. However, keeping this vehicle running at its peak requires strict adherence to specific fluid specifications and maintenance intervals. Using the correct lubricants ensures that the continuously variable transmission (CVT) shifts smoothly, the engine resists wear during cold starts, and the cooling system maintains optimal operating temperatures year-round. Because Subaru’s design relies heavily on precise fluid chemistry to manage heat and friction, substituting generic products can lead to premature wear or performance degradation.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – The premier choice for superior engine protection and extended drain intervals, ideal for the FB25 engine’s strict viscosity requirements.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – A robust option that offers 37% more cleaning power to combat sludge and deposits while providing long-lasting protection.
- AMSOIL Oil Filter (EA15K13) – Designed to capture smaller contaminants more effectively than standard filters, ensuring cleaner oil circulation and reduced engine wear.
- AMSOIL 100% Synthetic CVT Fluid – Specifically formulated for Subaru’s CVT transmissions to ensure smooth shifting and prevent metal-to-metal friction wear.
- AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube – Provides superior protection for the rear differential, controlling thermal runaway and protecting against rust and corrosion.
Essential Engine Oil for the FB25 Engine
The heart of your 2018 Subaru Forester is the FB25BA 2.5L four-cylinder engine. This powerplant is designed with tight tolerances and a direct injection system that benefits significantly from high-quality synthetic lubrication. The manufacturer specifies a viscosity of 0W-20 for all temperatures, which is critical for cold-start protection and fuel economy. When performing an oil change, the system requires approximately 5.1 quarts of fluid, including the filter replacement. It is essential to torque the drain plug to 31 ft-lbs and install a new washer on the drain bolt to prevent leaks.
For those seeking maximum performance, the AMSOIL Signature Series 0W-20 stands out as the top recommendation. This full synthetic oil provides up to 25,000 miles of protection in personal vehicles, offering 75% more protection against horsepower loss and wear compared to the industry standards. It is rigorously tested to handle the extreme thermal stress placed on modern engines. For drivers who prefer a slightly longer interval without sacrificing protection, the AMSOIL Extended-Life 0W-20 is an excellent alternative. It features enhanced cleaning power to keep the engine running smoother for longer periods, reducing the formation of harmful deposits.
Owners of higher-mileage Foresters with over 75,000 miles should consider the AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil. This formula includes a boosted detergent package and anti-wear additives that help clean sludge and prevent oil consumption, ensuring the engine continues to run efficiently. Additionally, the AMSOIL OE 0W-20 offers a cost-effective solution that still outperforms conventional oils and meets OEM requirements.
Transmission and Drivetrain Fluids
The 2018 Subaru Forester is renowned for its all-wheel-drive capability, which places unique demands on the transmission and differential systems. The Automatic Transmission uses a Lineartronic CVT (CVT8), which requires specific fluid to maintain the frictional properties necessary for the pulley system to operate smoothly. The total fill capacity for the automatic transmission is 13.1 quarts. Using the wrong fluid can lead to shuddering, slipping, and costly repairs.
The AMSOIL 100% Synthetic CVT Fluid is engineered to provide exceptional metal-to-metal frictional properties, ensuring the belt and pulleys engage correctly under load. It helps prevent the wear and overheating common in CVT systems subjected to towing or stop-and-go traffic.
For the manual transmission variant, the system requires approximately 7 pints of fluid, with a drain plug torque of 33 ft-lbs. If your Forester has a manual transmission, the AMSOIL SEVERE GEAR 75W-90 is a highly recommended alternative to the GL-5 SAE 75W-90 specification. It contains friction modifiers that improve driveability and fuel efficiency while providing advanced protection against wear and rust.
The rear differential also requires regular attention. The capacity for the rear differential is 1.7 pints. For this application, the AMSOIL SEVERE GEAR 80W-90 offers a robust solution that protects against the high loads typical of all-wheel-drive torque split. Alternatively, the AMSOIL SEVERE GEAR 75W-110 provides extended thermal stability for severe service conditions.
Cooling and Brake Systems
Maintaining the cooling system is vital for the longevity of the FB25 engine. The coolant capacity varies by configuration, with the CVT system holding 8.1 quarts and the MT7.9 holding 7.9 quarts. For these applications, the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a perfect match. It is a 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
For those who prefer a concentrated formula that requires mixing with distilled water, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers superior protection. It exceeds standards for metallic corrosion and erosion, ensuring the cooling system remains free from rust and scale buildup.
Safety is paramount, and the braking system of your Forester relies on high-quality hydraulic fluid. The recommended fluid is DOT 3. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid provides excellent ABS and traction-control responsiveness. Its stable viscosity over a wide temperature range ensures consistent braking performance, regardless of whether you are driving in freezing winters or hot summer conditions.
Filters and Maintenance Accessories
Regular maintenance goes beyond just changing the oil. The AMSOIL Oil Filter is a critical component that ensures the lubricating oil remains clean. It offers filtering efficiency of 99 percent at 20 microns and allows for lower restriction, keeping engine parts lubricated. For an OEM-style experience, the WIX Oil Filter is another premium choice that offers improvements over standard equipment filters.
Keeping the engine breathing clean air is equally important. The WIX Air Filter is designed to trap contaminants effectively, protecting internal engine components from abrasive particles. For owners looking to optimize their fuel system, the AMSOIL P.i. Performance Improver is a powerful gasoline additive that restores horsepower and cleans GDI fuel injectors.
Additional Products for Complete Protection
To maintain your Subaru Forester in peak condition, AMSOIL offers a wide range of specialized products. The AMSOIL Gasoline Stabilizer is ideal for seasonal storage, keeping fuel fresh for up to 12 months and preventing varnish buildup. For engine preservation during long periods of inactivity, the AMSOIL Engine Fogging Oil provides a highly effective rust preventive that protects internal components.
Cleaning and protection are also available for the exterior and undercarriage. The AMSOIL Heavy-Duty Metal Protector leaves a protective coating that resists salt and moisture, while the AMSOIL Silicone Spray offers a dry lubricating film for rubber and plastic parts. For general maintenance, the AMSOIL Synthetic Multi-Purpose Grease provides outstanding low-temperature pumpability and load-carrying performance for chassis components.
Keep your vehicle looking its best with AMSOIL Miracle Wash, a waterless wash that leaves a fantastic shine and protective finish. The AMSOIL High-Foam Car Shampoo is perfect for bucket washing, breaking down dirt gently on delicate finishes. For interior care, the AMSOIL Interior Detailer and the Scent Free version offer 90-day UV protection and odor elimination.
Finally, for keeping your vehicle free from road grime, the AMSOIL Mudslinger creates a protective barrier against mud, dirt, and snow. The AMSOIL Brake and Parts Cleaner is essential for maintaining brake components, while the AMSOIL Glass Cleaner ensures clear visibility with a streak-free finish.
About the 2018 Subaru Forester
The 2018 Subaru Forester represents a pivotal generation in the compact SUV market, known for its unique combination of sedan-like handling and rugged utility. Based on Subaru’s Global Platform, this model year offers a lower center of gravity, which significantly enhances stability and cornering capability compared to previous generations. The standard 2.5-liter FB-series engine, producing around 182 horsepower, provides a smooth and reliable power delivery that is well-suited for both daily commuting and weekend adventures. The inclusion of the symmetrical all-wheel-drive system is a hallmark of the brand, giving owners confidence in rain, snow, and uneven terrain.
One of the standout features of the 2018 Forester is its “X-Mode,” a dual-function system designed to enhance off-road capability. When activated, X-Mode optimizes the vehicle’s traction control and hill descent control, making it easier to navigate steep inclines and slippery surfaces. The interior is spacious, featuring a generous cargo area that is ideal for outdoor enthusiasts carrying gear. The 125-horsepower turbocharged option (if equipped as a 2.0XT model) offers even more punch for highway merging and overtaking.
While the 2018 Forester is a highly regarded vehicle, owners should be aware of common issues that can affect its longevity. One frequent concern is the potential for CVT transmission shuddering or hesitation, often caused by fluid breakdown or contamination. Using a high-quality synthetic CVT fluid can mitigate these issues and extend the life of the transmission. Another area of focus is the engine’s oil consumption, which can vary in FB-series engines; using high-performance synthetic motor oils with improved viscosity stability can help control this consumption and reduce oil top-offs. Additionally, some owners report rusting of the front strut towers, particularly in regions that use road salt. Applying a rust inhibitor like metal protector can provide an extra layer of defense against corrosion. Lastly, carbon buildup on direct injection intake valves can occur over time; using a fuel system cleaner regularly helps prevent this buildup and maintains optimal engine performance. By addressing these potential areas with the right lubricants and additives, owners can ensure their Forester remains a reliable and capable companion for years to come.