Maintaining the health of your 1987 Jeep Comanche with the 2.5L engine requires precision when selecting lubricants. This iconic compact truck relies on proper fluid chemistry to handle the unique demands of its inline-four powerplant and its various transmission and drivetrain configurations. Using the correct oil viscosity and high-performance additives can significantly extend the service life of your engine, transmission, and differential components. This guide details the specific AMSOIL products recommended for every lubrication point on your vehicle.
Recommended AMSOIL Products
- AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil – The top-tier choice for maximum protection against wear, designed to withstand severe service and extreme temperatures while maintaining viscosity for up to 25,000 miles.
- AMSOIL Extended-Life 10W-30 100% Synthetic Motor Oil – An excellent option offering superior cleaning power and protection for 20,000 miles, helping to keep your older engine running smoothly.
- AMSOIL OE 10W-30 100% Synthetic Motor Oil – A budget-friendly synthetic alternative that fights sludge and deposits, providing reliable protection for normal driving conditions.
- AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil – Specifically formulated for vehicles over 75,000 miles with boosted detergents to reduce sludge and improve engine performance.
- WIX Oil Filter – Features premium filtration media designed to trap contaminants and protect the engine longer than standard factory filters.
- WIX Air Filter – Ensures a clean air supply to the engine, improving efficiency and protecting internal components from abrasive dust and dirt.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A ready-to-use 50/50 pre-mix that protects cooling system metals and hoses for up to 150,000 miles or five years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, eco-friendly option that offers superior boiling points and protection against corrosion for extended service life.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing and extreme temperatures, preventing shudder and ensuring smooth shifts.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – A versatile synthetic fluid that guards against leaks and promotes shudder-free shifts in automatic transmissions.
- AMSOIL Torque-Drive 100% Synthetic Automatic Transmission Fluid – Formulated to resist thermal and oxidative degradation, ensuring a long fluid life in automatic transmissions.
- AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube – Provides advanced protection against wear and thermal runaway in manual transmissions and differentials.
- AMSOIL SEVERE GEAR 75W-110 100% Synthetic Gear Lube – A heavier viscosity option ideal for heavy-duty applications and limited-slip differentials requiring high film strength.
- AMSOIL SEVERE GEAR 80W-90 100% Synthetic Gear Lube – Excellent for general purpose use in gear sets, controlling temperature and protecting seals.
- WIX Transmission Filter – Designed for the 1987 Comanche automatic transmission to ensure clean fluid flow and protect the valve body.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS responsiveness and a high boiling point for consistent braking under stress.
- AMSOIL SEVERE GEAR 75W-140 100% Synthetic Gear Lube – The heavy-duty choice for rear differentials and transfer cases requiring extreme pressure protection.
- AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube – Engineered for extended service intervals while maintaining high-load protection for gears and bearings.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Keeps seals soft to prevent leaks while reducing noise and friction in the steering system.
- AMSOIL P.i. Performance Improver Gasoline Additive – Restores up to 14% horsepower and cleans fuel injectors to improve fuel economy and drivability.
The 1987 Jeep Comanche represents a pivotal era for the brand, bridging the gap between the rugged, utilitarian vehicles of the 1970s and the modern SUVs of today. As a compact pickup truck, the Comanche was built on the proven chassis of the Cherokee, sharing much of its suspension geometry and body structural integrity. The 2.5L inline-four engine, often referred to as the “Iron Duke,” was a workhorse known for its simplicity and durability rather than raw speed. It was designed to offer respectable fuel economy for a four-cylinder vehicle of its time, making it an economical choice for daily driving or light hauling.
Owners of this vehicle typically appreciate its off-road capability. Even with the smaller engine, the Comanche was a favorite among budget-conscious off-roaders because of its lightweight design and available four-wheel-drive system. The transfer case options, such as the NP231 or NP242, allowed for flexible driving in various terrains. Whether used for hauling tools to a job site or crawling over trails in the mountains, the vehicle’s reputation rests on its ability to remain reliable under heavy loads.
However, as a nearly 40-year-old vehicle, the Comanche is susceptible to specific maintenance challenges that synthetic lubricants can help mitigate. One common issue is oil consumption and sludge buildup in the engine, particularly if the vehicle has seen high mileage. The 2.5L engine can develop varnish in the valve train and oil passages over time, leading to reduced performance and harder starts. High-quality synthetic oil with robust detergent packages helps dissolve these deposits and keeps critical moving parts clean.
Another prevalent problem involves the cooling system, which can suffer from rust and corrosion in the aluminum components over the decades. The original factory coolant often degrades, leading to leaks and potential overheating, which can be catastrophic for the engine. Using a premium antifreeze like AMSOIL’s Propylene Glycol or OAT formulations provides superior corrosion inhibition and helps prevent gasket and hose failures that are common in vintage Jeeps.
Transmission issues are also a significant concern for owners of this model. The AW4 automatic transmission, found in many of these trucks, is known to develop shudder, slipping, or harsh shifting as the vehicle ages. The fluid can break down under heat, leading to wear on the clutch plates and torque converter. Switching to a high-performance synthetic automatic transmission fluid like the Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid can restore smooth shifting characteristics and extend the life of the transmission significantly. Furthermore, the manual transmission options, such as the AX4 or AX5, benefit from high-quality SEVERE GEAR 75W-90 100% Synthetic Gear Lube to reduce noise and prevent the brass synchronizers from wearing out prematurely.
Finally, the differential and transfer case units can be prone to leaking seals and noise due to worn gears or low-viscosity fluids. Synthetic gear lubes provide a stronger film strength that protects the hypoid gears from wear and helps seals remain pliable, reducing the frequency of drips and leaks. By addressing these common failure points with the right lubricants, owners can keep their 1987 Comanche running smoothly for years to come.