Proper lubrication is the lifeblood of your 1987 BMW M6, particularly given the demands placed on its high-revving 3.5-liter S38B35 inline-six engine. Whether you are participating in track days, driving on winding roads, or simply preserving the vehicle’s longevity in daily use, the quality of fluids you choose directly impacts performance and durability. Standard conventional oils often break down under the high temperatures and stress levels generated by this classic German sports car, leading to increased wear on critical components like flat-tappet camshafts and valve trains.
Recommended AMSOIL Products
- AMSOIL Premium Protection 10W-40 100% Synthetic Motor Oil – A high-zinc formula designed to guard against wear and is ideal for protecting flat-tappet cams found in this era of BMW engines.
- AMSOIL Extended-Life 10W-40 100% Synthetic Motor Oil – Offers up to 20,000 miles of guaranteed protection and 37% more cleaning power to keep the engine running smoother for longer.
- AMSOIL 5W-40 MS 100% Synthetic European Motor Oil – Specifically engineered with a precise blend of synthetic base oils and premium additives to meet the unique demands of European vehicles.
- MANN-FILTERS Oil Filter – Features premium media that offers improvements over original equipment manufacturer branded filters to ensure optimal oil flow and contamination control.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Provides reserve protection during heavy use and abuse, remaining fluid even in sub-zero temperatures.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Promotes smooth, shudder-free shifts and guards against leaks while resisting harmful sludge.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with stable viscosity across a wide temperature range.
- AMSOIL SEVERE GEAR® 80W-90 100% Synthetic Gear Lube – Contains friction modifiers for limited-slip applications and helps reduce operating temperatures in the differential.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Offers advanced protection against wear and controls thermal runaway while protecting against rust and corrosion.
- AMSOIL SEVERE GEAR® 75W-110 100% Synthetic Gear Lube – Provides a high-viscosity solution for limited-slip differentials that need extra protection under heavy loads.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid formulation that exceeds OEM requirements and protects all cooling system metals and hoses.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated coolant offering protection for up to 150,000 miles and 5 years, with superior corrosion resistance.
- AMSOIL P.i. Performance Improver Gasoline Additive – Restores fuel injectors to 100% flow rate and helps improve fuel economy and combustion efficiency.
The engine bay of the 1987 BMW M6 is a masterpiece of engineering, housing the S38B35 engine, a direct descendant of the legendary M88/1 and M88/3 block. For this powerplant, the correct oil viscosity is critical to ensuring proper oil pressure at operating temperatures while maintaining a protective film during cold starts. The manufacturer specifies a capacity of 6.1 quarts when changing the oil with a filter replacement. After refilling, it is essential to check the oil level to ensure accuracy, as the S38 engine is sensitive to oil starvation if not filled correctly. The oil drain plug torque specifications are also critical during service, with various bolt sizes requiring specific torque values of 19 ft/lbs, 45 ft/lbs, or 26 ft/lbs depending on the plug configuration.
Beyond the engine, the M6’s automatic transmission (4HP-22) requires a fluid that can handle the torque output of the inline-six without slipping or shuddering. A total fill for the 4-speed transmission requires 7.9 quarts, while an initial fill is approximately 3.2 quarts. The S38 engine also utilizes a manual transmission in certain configurations, requiring specific fluid types for the 5-speed unit. The rear differential is another critical area, requiring GL-5 gear lubricant. AMSOIL synthetic gear lubes are particularly beneficial here as they help control thermal runaway, a common issue in older differentials that have seen significant service. The rear differential capacity is 3.8 pints, and using a synthetic lube extends the life of the seals and gears, reducing the likelihood of leaks and metal debris in the differential.
Keeping the Cooling System and Brakes in Top Form
A cooling system failure can quickly lead to catastrophic engine damage, especially in a high-performance vehicle like the M6. The radiator capacity for this model is 11.1 quarts. AMSOIL antifreeze and coolant options provide protection up to 150,000 miles or 5 years, whichever comes first. This extended interval reduces the frequency of flushes, saving time and effort while ensuring the engine temperature remains stable under load. The formulation is phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free, which helps preserve the integrity of gaskets and hoses that may have aged over the decades.
Brake fluid is another often-overlooked fluid that plays a vital role in the safety and performance of the M6. The vehicle requires DOT 3 and DOT 4 compatible hydraulic brake fluid. AMSOIL synthetic brake fluid provides a stable viscosity over a wide temperature range, ensuring consistent pedal feel and excellent ABS responsiveness. This is particularly important for a car of this vintage that may be used for spirited driving where repeated braking can boil standard fluid, leading to a spongy pedal and reduced stopping power.
For fuel system maintenance, the AMSOIL P.i. Performance Improver is highly recommended. This gasoline additive helps restore fuel injectors to 100% flow rate after just one tank of fuel. It also reduces the need for higher-octane fuel and helps prevent carbon buildup, which can be a concern in direct injection or high-compression engines. By keeping the fuel system clean, the engine can maintain its designed power output and efficiency, reducing the risk of pre-ignition knock.
Vehicle Background
The 1987 BMW M6 is a rare and celebrated automotive icon, representing the pinnacle of German engineering during the late 1980s. Based on the E24 generation of the 6 Series, the M6 was not just a luxury coupe but a high-performance sports car that combined grand touring comfort with genuine track capability. Powered by the legendary 3.5-liter S38B35 inline-six engine, this powerplant was a naturally aspirated masterpiece capable of producing around 256 to 268 horsepower, depending on the specific market and year. The engine was renowned for its high-revving nature, smooth power delivery, and exceptional durability, thanks to a cast-iron block and individual throttle bodies that fed each cylinder.
One of the defining characteristics of the M6 is its rear-wheel-drive layout and the sophisticated suspension setup that BMW tuned for both comfort and precision handling. The car features a solid, rigid chassis that absorbs road imperfections while providing sharp steering response. This balance made it a favorite among enthusiasts who enjoyed driving on winding roads, as well as those who participated in road racing events. The M6 was positioned as a halo vehicle for BMW, competing with other high-end grand tourers but offering a more engaging and driver-focused experience. Its production numbers were relatively low, making it a highly sought-after collector’s item today.
Despite its robust design, the M6 does face some common issues that owners should be aware of, particularly as the vehicle ages. One frequent problem is oil leaks from the valve cover gaskets and the oil filter housing gasket, which can lead to oil dripping onto the exhaust manifold and creating smoke. Using high-quality synthetic oils like those recommended here can help mitigate some of these issues by providing better sealing properties and resisting breakdown at high temperatures. Another common issue is the degradation of the cooling system components, such as the plastic radiator end tanks, which can crack over time. While a fluid change does not replace these parts, using a compatible coolant helps prevent corrosion that can accelerate the wear on older metal components.
Owners of the M6 also report issues with the automatic transmission, particularly shuddering or harsh shifts, which can be attributed to worn clutches or old fluid. Regular fluid changes with a high-performance synthetic transmission fluid can help smooth out shifts and protect the internal components from wear. Additionally, the rear differential in some models can suffer from noise or wear, especially if the original gear oil was not changed frequently. Using a synthetic gear lube with friction modifiers can help reduce noise and extend the life of the limited-slip clutch pack. By addressing these common problems with the right AMSOIL products, owners can keep their 1987 BMW M6 running smoothly and preserve its value for years to come.
Maintaining a 1987 BMW M6 requires a commitment to quality and precision. The vehicle’s design calls for fluids that can withstand the rigors of high performance while protecting the intricate components of the engine and drivetrain. By selecting the correct AMSOIL products, you are not just changing fluids; you are investing in the long-term health and performance of a classic machine. From the high-zinc motor oil that guards the camshaft to the synthetic gear lube that keeps the differential running quietly, every product plays a crucial role. Whether you are driving the M6 to a show or taking it to the track, using the recommended lubricants ensures that the car remains reliable and responsive.
Ultimately, the 1987 BMW M6 is a vehicle that deserves the best care possible. Its legacy is built on the foundation of superior engineering, and it continues to deliver an unparalleled driving experience for those who know how to maintain it. With the right fluids and regular maintenance, this classic sports car can continue to provide the thrill and reliability that BMW owners have come to expect. By following the recommendations outlined here, you ensure that your M6 remains a capable and enjoyable driver for many years to come, honoring the craftsmanship that made it a true automotive legend.