The 1987 Buick Somerset equipped with the 3.0L six-cylinder engine relies on high-quality lubricants to maintain its operational integrity and longevity. As an older vehicle, the Somerset benefits significantly from modern synthetic technologies that outperform conventional oils of the era. Using the correct viscosity and specification is crucial for the 3.0L engine to ensure proper protection against wear, sludge, and heat breakdown. Whether you are maintaining a daily driver or a collector’s item, adhering to the manufacturer’s specifications while utilizing premium synthetic fluids can prevent common issues associated with high-mileage vehicles of this vintage.
Recommended AMSOIL Products
- AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil – The top-tier choice offering up to 25,000 miles of protection and exceptional wear resistance for the 3.0L engine.
- AMSOIL Extended-Life 10W-30 100% Synthetic Motor Oil – Provides a balanced approach with extended drain intervals and enhanced cleaning power for older engines.
- AMSOIL OE 10W-30 100% Synthetic Motor Oil – A cost-effective synthetic option that meets original equipment specifications without compromising quality.
- AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil – Specifically formulated with seal conditioners and detergents for engines exceeding 75,000 miles to reduce leaks and sludge.
- AMSOIL Oil Filter – Engineered with advanced filtration media to capture smaller contaminants than conventional filters, ensuring cleaner oil circulation.
- WIX Oil Filter – A premium aftermarket alternative offering robust filtration performance compatible with the Somerset’s lubrication system.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – An extended-life formula that protects cooling system metals and prevents corrosion for up to 150,000 miles.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A safer, concentrated coolant option that offers superior freeze and boil-over protection.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand the heat and stress of the THM125C transmission, protecting against wear and fluid breakdown.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Meets original equipment standards while providing the benefits of full synthetic lubrication.
- AMSOIL 5W-30 Manual Synchromesh Transmission Fluid – Ideal for manual transmissions requiring GL-30/GL-31 specifications, offering smooth shifting and reduced wear.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Maintains stable viscosity over a wide temperature range for consistent braking performance and ABS responsiveness.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Protects seals and reduces noise, extending the life of the power steering system.
Proper lubrication is not merely about filling a reservoir; it is about maintaining the health of every moving part within the 1987 Buick Somerset. The engine of this vehicle, specifically the 3.0L inline-six, operates under conditions that demand oils with superior thermal stability. Conventional oils from the 1980s would break down relatively quickly under the heat and shear stress of modern driving, but AMSOIL synthetic motor oils are engineered to resist oxidation and maintain their viscosity grade longer. This protection is vital for engines that may have accumulated significant wear, as synthetic oils can help fill microscopic gaps in worn piston rings and cylinder walls, reducing oil consumption and extending engine life.
Beyond the engine, the Somerset’s transmission requires specific attention. The THM125C automatic transmission, often found in this model, benefits greatly from synthetic fluids that resist shear stability issues and oxidation. Heat is the primary enemy of transmission fluid, leading to the formation of varnish and sludge that can clog valves and lead to harsh shifting or failure. Using a dedicated synthetic automatic transmission fluid ensures that the fluid remains fluid in extreme temperatures while providing a protective film on clutch plates and gears. For those equipped with a manual transmission, the 5W-30 Manual Synchromesh Transmission Fluid is formulated to reduce friction and wear, ensuring smooth gear engagement even in colder climates.
The cooling system is another critical area where fluid choice impacts reliability. The 1987 Somerset’s cooling system is designed to operate within specific temperature ranges, and using the correct antifreeze formulation is essential to prevent rust, corrosion, and electrolysis. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant offers a unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses. This longevity-focused coolant can last up to 150,000 miles, reducing the frequency of flushes and the risk of overheating caused by old, acidic coolant eating away at the radiator and heater core.
Brake and steering systems also rely on specialized fluids to function safely and reliably. The hydraulic brake system benefits from a synthetic brake fluid that does not absorb moisture as readily as conventional DOT 3 fluids, maintaining a higher boiling point and preventing spongy pedal feel. Similarly, the power steering system can suffer from seal drying and noise if standard fluids are used. The 100% Synthetic Multi-Vehicle Power Steering Fluid is designed to keep seals soft and pliable while providing excellent high-temperature protection, ensuring quiet and responsive steering. Together, these fluids create a comprehensive maintenance regimen that addresses the specific needs of this classic vehicle.
Vehicle Background
The 1987 Buick Somerset holds a unique place in the history of General Motors’ product lineup, serving as a distinct embodiment of the American compact car market of the late 1980s. As part of the Buick brand, the Somerset was marketed as a fuel-efficient, reliable companion for the commuter and the budget-conscious buyer. It shared its platform with the Oldsmobile Firenza, a relationship typical of GM’s “badge engineering” strategy during this era. This shared architecture meant that while the styling cues were tailored to the Buick identity, the mechanical underpinnings were robust and proven, offering a sense of familiarity for owners of other General Motors vehicles.
Powered by the 3.0L V6 engine code [L], the Somerset offered a significant improvement in performance and smoothness over the four-cylinder engines that dominated the compact segment. This engine, known for its durability and adequate power delivery, was a staple of GM’s L-body and J-body platforms. The 3.0L provided a driving character that was neither overly aggressive nor sluggish, striking a balance that appealed to families and individuals looking for a dependable daily driver. The car’s design philosophy focused on comfort and economy, featuring a soft suspension tune and a quiet cabin that distinguished it from more sport-oriented rivals.
Despite its reliability, the 1987 Buick Somerset is not without its known challenges that modern owners should be aware of. Over time, the engine’s timing chain tensioners can wear, leading to rattling noises, particularly on startup. This issue can be mitigated by using high-detergent AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil that help clean the tensioner mechanisms and provide better lubrication to the chain guides. Another common issue involves the carburetor or fuel injection system, depending on the specific model year and engine configuration, where fuel system deposits can accumulate over decades of storage or infrequent driving. AMSOIL P.i. Performance Improver can help clean these deposits and restore performance.
Seal hardening is a prevalent concern in older vehicles, often leading to oil leaks from the valve cover gaskets or front and rear main seals. The use of a high-mileage motor oil, which contains seal conditioners, can help swell and soften these aging rubber components, reducing or preventing leaks. Furthermore, the automatic transmission fluid in these vehicles can degrade, leading to shifting issues or failure. Synthetic transmission fluids offer superior thermal stability and film strength, which can extend the life of the transmission components and improve shift quality. Finally, the cooling system can suffer from corrosion and blockages due to old antifreeze; regular flushing with a high-quality ethylene glycol antifreeze can prevent overheating and protect the radiator and water pump. By addressing these common areas with the right lubricants and fluids, owners can keep their 1987 Buick Somerset running smoothly for years to come.