Maintaining the 1985 Ford Bronco II with the 2.8L inline-six engine requires precise attention to lubrication specifications to ensure longevity and performance. This classic small SUV, powered by the Ford “V6-2800” (engine code S), was a staple for drivers seeking off-road capability in a compact package. Whether you are driving daily, towing light loads, or preparing for extended storage, using the correct fluids prevents wear and maintains efficiency. The following guide details the exact fluid capacities, types, and recommended AMSOIL products tailored for this specific vehicle configuration.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Provides the highest level of protection with a guaranteed interval of up to 25,000 miles for this vehicle.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Offers extended protection for up to 20,000 miles while maintaining superior cleaning power.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A cost-effective synthetic option designed to outperform conventional oils and provide OEM-level mileage protection.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Specifically formulated for vehicles over 75,000 miles with enhanced detergents to reduce sludge.
- AMSOIL Oil Filter – Features 99% filtering efficiency at 20 microns and allows lower restriction for better lubrication.
- WIX Oil Filter – Offers premium media with improvements over original equipment manufacturer branded filters.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid formulation that protects cooling system metals, gaskets, and hoses.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated formula that must be mixed, providing protection for up to 150,000 miles.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures while remaining fluid in sub-zero conditions.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Guards against leaks and promotes smooth, shudder-free shifts for the A4LD transmission.
- AMSOIL Torque-Drive 100% Synthetic Automatic Transmission Fluid – Fights thermal and oxidative degradation to provide long oil life for automatic transmissions.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS responsiveness and stable viscosity across a wide temperature range.
- AMSOIL SEVERE GEAR 80W-90 100% Synthetic Gear Lube – Advanced protection against wear and thermal runaway with friction modifiers for limited-slip applications.
- AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube – Helps reduce operating temperatures and extends equipment life in Dana 35 and rear differentials.
- AMSOIL SEVERE GEAR 75W-110 100% Synthetic Gear Lube – Ideal for limited-slip differentials requiring 75W-110 viscosity for optimal clutch engagement.
Ensuring your 1985 Bronco II receives the right lubrication starts with the engine, the heart of the vehicle. The 2.8L engine, often referred to as the Ford “V6-2800” or engine code S, is a naturally aspirated inline-six that relies on consistent oil pressure to manage internal friction. When performing an oil change, the total system capacity is 5.0 quarts, including the filter. It is critical to remove the dipstick during the refill process to provide adequate venting, allowing the oil to flow freely into the crankcase before checking the final level. The drain plug should be torqued to between 15 and 20 ft/lbs to ensure a secure seal without damaging the threads. For the 1985 Bronco II, 5W-30 is the recommended viscosity for all operating temperatures. This grade offers excellent flow in cold starts while maintaining a protective film at high operating temperatures.
For those seeking maximum durability, the AMSOIL Signature Series 5W-30 is the premium choice, offering up to 25,000 miles of protection in normal service conditions. Its synthetic formulation contains advanced anti-wear additives that significantly reduce horsepower loss and engine wear. If your driving patterns involve extended intervals or high-mileage usage, the Signature Series outperforms conventional oils and even meets the rigorous demands of turbocharged engines in other applications, though the Bronco II remains naturally aspirated. For owners prioritizing value without sacrificing synthetic quality, the AMSOIL OE 5W-30 provides 100% synthetic protection designed to fight sludge and deposits effectively. It is engineered to meet or exceed original equipment specifications while offering extended service life. The AMSOIL Extended-Life 5W-30 serves as a robust middle ground, delivering 20,000 miles of guaranteed protection with enhanced cleaning power to keep the engine running smoothly. For vehicles with more than 75,000 miles, the AMSOIL High-Mileage 5W-30 is specifically designed with boosted detergents to reduce sludge by 67% and contains seal conditioners to help maintain oil pressure.
Pairing the correct oil with a high-efficiency filter is essential for maximizing engine life. The oil filter traps wear-causing contaminants, preventing them from recirculating through the engine. The AMSOIL Oil Filter (EAO15) is recommended for its superior filtering efficiency and lower restriction, which keeps engine parts better lubricated. It offers extended service life to match the synthetic oil intervals. For those preferring an aftermarket option, the WIX Oil Filter (51515) utilizes premium media that offers improvements over OEM-branded filters, ensuring reliable filtration for every oil change.
Beyond the engine, the cooling system is critical for the longevity of the Bronco II’s aluminum components. The total fill capacity for the cooling system is 7.4 quarts if the vehicle is equipped with air conditioning and 7.9 quarts if it is not. AMSOIL offers two primary antifreeze options. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a 50/50 pre-mixed formulation that requires no mixing and protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years. It is phosphate-, nitrate-, and silicate-free, making it compatible with a wide variety of vehicle materials. For those who prefer a concentrated option, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers protection for up to 150,000 miles (or significantly longer in heavy-duty applications) when mixed with distilled water. It greatly surpasses standards for metallic corrosion and erosion, ensuring your cooling system remains robust against the rigors of off-road driving and highway cruising.
The 1985 Bronco II typically features the A4LD four-speed automatic transmission. Fluid levels and capacities vary based on the drivetrain configuration. For a four-speed rear-wheel-drive (RWD) A4LD transmission, the total fill capacity is 9 quarts. For the four-speed all-wheel-drive (4WD) configuration, the total fill capacity increases to 10 quarts. An initial fill requires 3 quarts. Proper automatic transmission fluid is vital to prevent shuddering, slipping, and overheating, which can occur under the stress of 4WD operation or heavy towing. AMSOIL Signature Series Multi-Vehicle ATF is highly recommended for its ability to withstand elevated temperatures and thermal breakdown, remaining fluid even in sub-zero conditions. The AMSOIL OE Multi-Vehicle ATF is another excellent choice, protecting against wear, sludge, and leaks while promoting smooth, shudder-free shifts. The AMSOIL Torque-Drive ATF is formulated to fight thermal and oxidative degradation, providing long oil life and excellent cold-weather performance.
The Bronco II’s transfer case and differentials also require specific lubrication to handle the torque loads associated with four-wheel-drive systems. For the Warner 1350 transfer case, the capacity is 3 pints, with drain and fill plugs torqued to 14-22 ft/lbs. The front differentials vary by axle model; the Dana 28 requires 1.1 pints, while the Dana 35 requires 3.6 pints. The rear differential typically holds 5.1 pints. All these components generally require GL-5 rated gear lubricants, with 80W-90 being the standard specification for most applications. For limited-slip differentials, AMSOIL SEVERE GEAR 80W-90 is ideal as it contains friction modifiers that prevent chatter and ensure smooth operation. If your specific application requires 75W-90 or 75W-110 viscosity, the AMSOIL SEVERE GEAR 75W-90 and SEVERE GEAR 75W-110 options provide the necessary extreme pressure protection and thermal stability to control operating temperatures and prevent rust.
About the Vehicle
The 1985 Ford Bronco II represents a unique chapter in American automotive history, serving as the bridge between the rugged, full-size Bronco of the previous decade and the more car-like compact SUVs that followed. Introduced in 1983 as a replacement for the full-size Bronco in certain markets, the Bronco II was built on the Ford Ranger platform, sharing its unibody construction with the Ranger pickup and Bronco. This design choice made it significantly more manageable on paved roads while retaining substantial off-road credentials, a combination that appealed to a wide range of drivers in the 1980s.
Powered primarily by the 2.8L inline-six engine code S in the models covered here, the Bronco II offered a balance of power and efficiency that was rare for an off-road vehicle of its era. While not a powerhouse by modern standards, this engine was reliable and capable of pulling the 2.8L Bronco II through challenging terrain, including sand, mud, and snow. The vehicle featured a part-time four-wheel-drive system that allowed drivers to engage the front wheels when necessary, enhancing traction without the added weight and fuel consumption of a full-time system. The Bronco II was marketed as a “2-door SUV” and was available in various trim levels, though the distinction between them was often subtle to the average consumer.
Owners of the 1985 Bronco II typically appreciate its compact size, which made it easier to park and maneuver than larger SUVs of the time. It was often used as a daily driver, a weekend trail blazer, or a versatile utility vehicle for small families. The Bronco II’s reputation rests on its adaptability; it was a vehicle that could handle a commute to work as comfortably as it could tackle a dirt trail on a Saturday morning. This dual-purpose capability made it a favorite among those who needed a rugged vehicle without the size of a full-size truck. Over the years, the Bronco II has gained a cult following among enthusiasts who value its classic 80s styling and its role as a precursor to the modern compact SUV segment.
While the Bronco II was eventually replaced by the Ford Explorer in 1991, the 1985 model year stands out as a period of established reliability and enduring design. The 2.8L engine, while not as powerful as the later V6 options, is known for its longevity when properly maintained with high-quality lubricants. Regular maintenance, particularly keeping up with fluid changes and ensuring the four-wheel-drive system is properly lubricated, is key to keeping a 1985 Bronco II running smoothly for decades. Whether you are a collector restoring a classic or a driver enjoying a reliable off-roader, understanding the specific lubrication needs of this vehicle ensures it continues to perform as the versatile companion it was designed to be.