The 1987 Chrysler Conquest equipped with the 2.6-liter turbocharged four-cylinder engine demands a lubrication strategy that balances age-related wear with the specific needs of forced induction. This powertrain, identified by engine code [H] Turbo, was designed for spirited driving but has now accumulated significant mileage. Using the correct viscosity and fluid types is essential to maintain oil pressure, protect against turbocharger wear, and ensure smooth operation of the transmission and differential systems. This guide details the precise AMSOIL synthetic lubricants required to keep this classic Japanese-market icon running at its peak performance level.
Recommended AMSOIL Products
- AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil – Provides the highest level of engine protection against horsepower loss and wear, specifically formulated to protect turbochargers 72% better than industry requirements. This oil can be driven for up to 25,000 miles or one year between changes.
- AMSOIL Extended-Life 10W-30 100% Synthetic Motor Oil – Offers 37% more cleaning power to help keep the engine running smoother and longer, while guaranteeing protection for up to 20,000 miles between oil changes.
- AMSOIL OE 10W-30 100% Synthetic Motor Oil – A cost-effective 100% synthetic solution that fights sludge and deposits effectively while offering protection for up to 20,000 miles.
- AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil – Features unique chemistry and boosted detergents for vehicles with over 75,000 miles, reducing sludge by 67% and helping engines last longer with a guarantee for 12,000 miles.
- WIX Oil Filter – Features premium filtration media that offers improvements over original equipment manufacturer (OEM)-branded filters to ensure clean oil flow.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A ready-to-use, phosphate-free 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated formulation requiring mixing with distilled water, offering protection up to 150,000 miles or 5 years and greatly surpassing standards for metallic corrosion.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures, providing reserve protection during severe use and remaining fluid in sub-zero conditions.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Promotes smooth, shudder-free shifts while protecting against wear, sludge, and leaks for up to 100,000 miles.
- AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube – Designed for manual transmissions like the KM132-G, offering excellent seal compatibility and protection for brass synchronizers in all temperatures.
- 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 to prevent boiling.
- AMSOIL SEVERE GEAR® 80W-90 100% Synthetic Gear Lube – Advanced protection for rear differentials, controlling thermal runaway and helping reduce operating temperatures in both standard and limited-slip applications.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – A versatile choice for rear standard and limited-slip differentials, containing friction modifiers to prevent chatter in limited-slip units.
Proper lubrication is the cornerstone of longevity for the 1987 Chrysler Conquest. Because this vehicle features a 2.6-liter turbocharged engine, the oil pump and bearing clearances are under higher stress than a naturally aspirated engine of the same era. The engine requires exactly 5 quarts of oil when performing a change with a filter replacement. Maintaining the correct torque on the drain plug, between 26 and 32 ft/lbs, is critical to prevent leaks or stripped threads. The cooling system capacity is substantial at 9.5 quarts, requiring a robust AMSOIL Passenger Car & Light Truck Antifreeze & Coolant to handle the thermal cycles of a turbocharged engine.
Transmission and Drivetrain Fluids
The drivetrain of the 1987 Chrysler Conquest varies depending on the specific transmission installed, either a 4-speed automatic (L4N71B) or a manual unit. For the automatic transmission, a total fill requires 7.4 quarts, while an initial fill holds 5.3 quarts. Synthetic automatic transmission fluid is highly recommended to prevent shudder and protect against the heat generated during spirited driving or towing. The manual transmission, specifically the KM132-G five-speed model, requires 4.9 pints of 75W-85W or 80W AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube, making the AMSOIL SEVERE GEAR® 80W-90 100% Synthetic Gear Lube an ideal fit for all-season protection and brass synchronizer care.
The rear differential also plays a vital role in handling the power delivered to the wheels. Standard GL-5 differentials require either 2.7 pints of 80W-90 or 85W-90 lubricant depending on the ambient temperature range. For limited-slip differentials, a specific formulation is required to prevent seal damage and ensure smooth operation. The AMSOIL SEVERE GEAR® 80W-90 100% Synthetic Gear Lube line provides the necessary extreme pressure (EP) additives and friction modifiers to handle the load of a rear-wheel-drive sports coupe while reducing noise and vibration.
Maintenance and Seasonal Care
For vehicles that see less frequent use or are stored seasonally, AMSOIL offers specialized additives and stabilizers. The AMSOIL P.i.® Performance Improver gasoline additive can help restore up to 14% of horsepower by cleaning fuel injectors and reducing carbon buildup, which is particularly beneficial for older engines that may have accumulated deposits over decades of use. During winter storage, using AMSOIL Engine Fogging Oil can coat internal engine components to prevent rust and corrosion, ensuring the engine turns over freely when the weather warms up. Additionally, the AMSOIL Gasoline Stabilizer keeps fuel fresh for up to 12 months, preventing the varnish and gum buildup that can clog the fuel system of a vintage vehicle.
About the Vehicle
The 1987 Chrysler Conquest represents a fascinating chapter in automotive history, serving as a badge-engineered twin to the Mitsubishi Galant Lambda and the Dodge Conquest of the same era. It was one of Chrysler’s ambitious attempts to compete in the sporty coupe market, which was heavily dominated by Japanese manufacturers during the 1980s. The specific model discussed here features the 2.6-liter four-cylinder engine, a unit derived from Mitsubishi technology that was known for its relatively high compression ratio and turbocharged variant, offering a unique driving experience for its time. This engine code [H] denotes the turbocharged configuration, which provided a spirited drive that was surprisingly punchy for a four-cylinder displacement of 2.6 liters, a size that was quite common for engines of that vintage.
Owners of the 1987 Chrysler Conquest often appreciate the vehicle for its distinctive styling, which featured pop-up headlights and a sleek, aerodynamic profile that was ahead of its time. The car was designed to offer a blend of performance and practicality, with a rear-wheel-drive layout that provided excellent handling dynamics and a driver-centric feel. Despite its sporty intentions, the Conquest was a niche product, appealing to enthusiasts who valued engineering over mass-market appeal. The interior typically included sporty bucket seats and a dashboard layout that emphasized function and direct feedback from the road. While the vehicle may not have achieved the widespread sales of its domestic competitors, it has cultivated a dedicated following among collectors and driving enthusiasts who enjoy the challenge of maintaining a rare, performance-oriented classic car.
However, owning a vehicle from this era comes with specific mechanical challenges that modern synthetic lubricants are uniquely positioned to solve. One of the most significant issues faced by 1987 Chrysler Conquest owners is turbocharger wear. The bearings in the turbocharger can suffer from oil coking and sludge buildup, especially if the engine was subjected to hard driving without adequate cooling intervals. Using a high-quality 100% synthetic motor oil like the AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil provides superior thermal stability and resistance to breakdown, ensuring that the turbocharger bearings are constantly bathed in clean, lubricating oil even under extreme heat conditions.
A second common problem involves engine sludge and carbon deposits in the intake and combustion chambers. As vehicles age, older oil formulations break down more quickly, leading to the accumulation of varnish and carbon that can restrict oil flow and reduce compression. The enhanced detergent packages found in AMSOIL Extended-Life and High-Mileage oils help dissolve existing deposits and prevent new ones from forming, effectively cleaning the engine and restoring lost horsepower. This is particularly important for the 2.6-liter engine, which relies on precise clearances for efficient operation.
A third issue that plagues these vehicles is transmission shifting problems, including shuddering and hard shifts in the automatic models. Over time, transmission fluid can lose its frictional properties and become contaminated with metal particles and clutch material. This can lead to premature wear of the valve body and bands. Switching to a synthetic automatic transmission fluid like the AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid can restore smooth shifting characteristics and extend the life of the transmission components by resisting shear and oxidation far better than conventional fluids.
Finally, rear differential whine or gear noise is a prevalent complaint among owners of this model. The limited-slip differentials can be noisy if the gear lube is not of sufficient quality to handle the friction modifiers required. Using a dedicated synthetic gear lube like AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube ensures that the limited-slip components operate quietly and effectively, protecting the gears from the extreme pressure generated during acceleration and cornering. By addressing these specific mechanical needs with the correct synthetic lubricants, owners can extend the life of their 1987 Chrysler Conquest and enjoy its unique driving character for years to come.