The 1987 Mercedes-Benz 300E, equipped with the 3.0-liter inline-six engine (Code 103.983 W), represents a golden era of German engineering where durability and performance converge. Maintaining this classic vehicle requires more than just filling the reservoirs; it demands precise fluid selection that accounts for the specific metallurgy and tolerances of the M103 engine family. For enthusiasts looking to preserve the drivability and longevity of their 300E, choosing high-quality synthetic lubricants is essential, particularly when dealing with an engine that may have seen decades of service.
Recommended AMSOIL Products
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Specifically formulated for the precise tolerances of European gasoline, diesel, and hybrid vehicles, offering superior protection for the M103 engine.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – Provides excellent low-temperature flow and high-temperature stability, ideal for all driving conditions and temperatures.
- AMSOIL Oil Filter – Delivers 99 percent filtration efficiency at 20 microns, capturing wear-causing contaminants to extend engine life.
- WIX Oil Filter – Offers improvements over original equipment manufacturer (OEM)-branded filters with premium media.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A phosphate-free, ethylene glycol 50/50 pre-mix that protects the cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – Concentrated formulation that greatly surpasses standards for metallic corrosion and erosion.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Designed to withstand heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Offers excellent cold-weather performance and resistance to sludge, ensuring smooth and shudder-free shifts.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Provides excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Helps seals remain soft to prevent leaks while resisting heat for long fluid life and ensuring quiet operation.
- AMSOIL Gasoline Stabilizer – Keeps fuel fresh up to 12 months, protecting against varnish and gum buildup for stored seasonal equipment.
- AMSOIL Engine Fogging Oil – A highly-effective rust preventive designed to protect internal engine components during storage or long periods of inactivity.
- AMSOIL P.i. Performance Improver Gasoline Additive – Restores up to 14% horsepower and improves fuel economy while controlling pre-ignition knock.
- AMSOIL Upper Cylinder Lubricant Corrosion Inhibitor – Lubricates the fuel system and upper cylinders for improved engine health.
- AMSOIL Synthetic Multi-Purpose Grease – Resists thermal and oxidation degradation for long-term performance and outstanding low-temperature pumpability.
- AMSOIL Heavy-Duty Metal Protector – Contains special rust and corrosion inhibitor additives to protect against the effects of salt and moisture.
- AMSOIL MP Metal Protector – Cuts through rust and frees frozen components while displacing water.
- AMSOIL Silicone Spray – Protects with a dry lubricating film ideal for surfaces that may be damaged by conventional lubricants.
- AMSOIL Heavy-Duty Degreaser – Dissolves oil, tar, and grime quickly to remove sticky residue.
- AMSOIL Power Foam Carburetor and Induction-System Cleaner – Cleans deposits from ethanol and degraded fuel to maximize horsepower.
- AMSOIL Miracle Wash Waterless Wash and Wax Spray – Requires just two easy steps to leave vehicles with a fantastic shine and tough protective finish.
- AMSOIL Brake and Parts Cleaner – Quickly removes oil, grease, brake fluid and other contaminants from brake parts and other automotive components.
- AMSOIL Mudslinger Mud and Dirt Repellent – Provides a protective, non-stick layer of armor against the accumulation of mud, dirt and snow.
- AMSOIL Engine Degreaser – Professional-strength formula packed with powerful degreasing solvents that quickly and easily remove the toughest grease, dirt and grime.
- AMSOIL Glass Cleaner – Effectively cuts through grease and grime faster than other leading glass cleaners without streaks or haze.
- AMSOIL High-Foam Car Shampoo – High-foam formula that is hard on dirt but gentle on coatings and finishes.
- AMSOIL Exterior Ceramic Spray – Easy application that sheds water rapidly and protects against UV rays.
- AMSOIL Interior Detailer – Light Lemon – Multi-surface use with 90-day UV protection that traps and eliminates odors.
- AMSOIL Interior Detailer – Scent Free – Multi-surface use with 90-day UV protection that traps and eliminates odors.
Engine Oil and Filtration Specifications
Proper lubrication is the lifeblood of the 1987 Mercedes-Benz 300E’s M103 engine. This robust powerplant, known for its smooth power delivery and durability, requires oil that can withstand the unique demands of European engine designs. The engine capacity is 6.9 quarts when including a filter change, or 6.3 quarts if the oil cooler is not drained. On models equipped with an oil cooler, it is crucial to note that additional oil will be required if the cooler is drained to ensure full lubrication.
For the best protection, AMSOIL recommends using either the 5W-40 FS or the 0W-40 FS 100% Synthetic European Motor Oils. The 5W-40 FS is tailored for a broad range of temperatures, while the 0W-40 FS offers superior flow in extreme cold, making it an excellent choice for colder climates or for owners who frequently engage in short-trip driving where the engine does not fully warm up. Both oils feature a European formula with a precise blend of synthetic base oils and premium additives designed to protect the engine in any driving condition.
Filtration is equally critical for an aging classic. The recommended AMSOIL Oil Filter (EAO34-EA) provides a filtering efficiency of 99 percent at 20 microns. This high-efficiency filtration helps reduce engine wear by capturing contaminants that standard filters might allow to pass. For those preferring a premium aftermarket alternative, the WIX Oil Filter is also available. Both filters are designed to handle the demands of high-mileage engines and extended service intervals, keeping oil flow unrestricted and engine internals clean.
Transmission and Gear Lubrication
The 1987 300E comes equipped with either a 4-speed automatic transmission (722.3) or a manual transmission (717.4), depending on the specific configuration and market. Maintaining these transmissions with high-quality fluid is vital for preserving the smooth shifting characteristic that owners of the 300E cherish.
For the 4-speed automatic transmission, a total fill capacity is 7.7 quarts, with an initial fill of 6.6 quarts. AMSOIL offers two top-tier options: the Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid and the OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid. Both fluids are designed to protect against wear, resist harmful sludge, and guard against leaks. They ensure smooth, shudder-free shifts even under heavy loads or in extreme heat, extending the life of the transmission components.
If your 300E features the 5-speed manual transmission, it requires a specific GL5-rated fluid. The recommended capacity for this unit is 3.2 pints. Using a high-quality synthetic gear lubricant ensures that the gears remain protected against the high pressures found in manual transmissions, providing a smoother shifting experience and reducing wear on the synchronizers.
Cooling, Brakes, and Other Critical Fluids
The cooling system of the 300E requires approximately 9.5 quarts of AMSOIL Passenger Car & Light Truck Antifreeze & Coolant. For this vintage vehicle, using a modern, long-life antifreeze is highly recommended to prevent corrosion and overheating. The AMSOIL Passenger Car & Light Truck Antifreeze & Propylene Glycol Antifreeze and Engine Coolant is a phosphate-free, OAT formulation that protects all cooling system metals, gaskets, and hoses. It provides protection for up to 150,000 miles or 5 years, ensuring the engine stays at optimal operating temperatures.
Brake performance is paramount for safety, and the 300E’s hydraulic brake system benefits from the use of a high-quality synthetic AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid. The product exceeds original equipment manufacturer requirements, providing excellent responsiveness for ABS and traction control systems. It maintains stable viscosity over a wide temperature range, which is crucial for consistent braking performance in all weather conditions.
Additionally, the power steering system should be maintained with AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid. This fluid helps seals remain soft to prevent leaks, a common issue in older vehicles, and offers strong anti-wear protection. It is formulated for quiet operation, ensuring that the steering remains effortless and smooth.
About the Vehicle: A Legacy of German Engineering
The 1987 Mercedes-Benz 300E is a significant chapter in automotive history, serving as the flagship of the W124 chassis family. Introduced as a sedan with a luxurious interior and a sophisticated powertrain, the 300E became known for its exceptional build quality and enduring durability. The vehicle was powered by the M103 engine, a 3.0-liter inline-six that was celebrated for its smooth power delivery and mechanical robustness. This engine code, 103.983 W, denotes the specific configuration for the 300E, a model that blended sporty performance with sedan comfort.
Owners of the W124 chassis often describe these vehicles as “tanks” that can withstand the test of time. The 300E was not just a commuter car; it was a benchmark for safety and engineering excellence. Its design prioritized occupant protection, featuring a crumple zone structure that was advanced for its time. The driving character of the 300E is defined by a refined, silent ride and a steady acceleration that feels effortless, even at higher speeds. It sits as a prime example of the “Diesel” ethos applied to gasoline engines—reliable, efficient, and built to last for decades.
As with any vehicle of this age, there are common areas of concern that owners must monitor. One frequent issue is the degradation of rubber seals and hoses in the cooling and fuel systems, which can lead to leaks if not addressed with modern synthetic fluids that help maintain seal integrity. Another common problem involves oil leaks from the valve cover gaskets and rear main seal, which are often exacerbated by the breakdown of standard mineral oils. Using a high-quality synthetic motor oil like the AMSOIL European formulas can help mitigate these leaks by maintaining better viscosity and reducing the sludge that can cause seals to harden.
Additionally, the 4-speed automatic transmission in some models can suffer from shift harshness or fluid breakdown over time. Without proper fluid maintenance, the transmission may exhibit signs of wear or slipping. Regular fluid changes with a synthetic transmission fluid can restore smooth shifting and protect the internal components. Finally, owners should be aware of potential corrosion in the exhaust system or underbody components, particularly in regions where road salt is used. Applying protective sprays and using corrosion-inhibiting products like AMSOIL Heavy-Duty Metal Protector or AMSOIL MP Metal Protector can help preserve the structural integrity of the vehicle.
By addressing these specific needs with the right AMSOIL products, owners can ensure their 1987 Mercedes-Benz 300E continues to perform with the reliability and refinement that made it a legend. Whether used as a daily driver or a weekend cruiser, the 300E rewards its owner with a driving experience that few other vehicles of its era could match.