Maintaining your 1998 Mitsubishi Galant with the 2.4L engine (Engine Code 4G64 G) requires precise fluid selection to ensure longevity and performance. Using the correct lubricants protects critical components from wear, extends service intervals, and helps the vehicle handle various driving conditions, from daily commuting to more demanding loads. This guide outlines the specific fluids, capacities, and maintenance schedules tailored for this model.
Recommended AMSOIL Products
Below are the top-tier lubricants and filters designed to meet or exceed the factory specifications for this vehicle.
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Offers 75% more engine protection against horsepower loss and wear, suitable for up to 25,000 miles or one year.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Provides extended protection for up to 20,000 miles with enhanced cleaning power to keep the engine running smoother.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A budget-friendly option that fights sludge and deposits, delivering OEM-level protection for standard mileage intervals.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Specifically formulated for engines over 75,000 miles with boosted detergents and reduced sludge.
- AMSOIL Oil Filter – Delivers 99% filtering efficiency at 20 microns to trap wear-causing contaminants and extend service life.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed 50/50 formulation protecting the cooling system for 150,000 miles or five years.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Withstands heat and heavy towing while maintaining fluidity in sub-zero temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Provides a stable viscosity over a wide temperature range for excellent ABS and traction-control responsiveness.
The engine compartment of your 1998 Mitsubishi Galant is a precision ecosystem where every fluid plays a distinct role in preserving mechanical integrity. For the 2.4-liter 4G64 engine, the capacity for engine oil is 4.5 quarts when a filter replacement is included. It is critical to verify the oil level after refilling, ensuring you do not overfill the crankcase, which can lead to foaming and reduced lubrication efficiency. The recommended oil grade for this engine is SAE 5W-30, which is preferred for its balance of cold-start flow and high-temperature protection. While 10W-30 is listed as an option for temperatures above -18°C, the 5W-30 viscosity range offers superior performance across a broader spectrum of weather conditions. When performing an oil change, the oil drain plug should be torqued to between 26 and 32 foot-pounds to ensure a secure seal without damaging the threads. AMSOIL Signature Series 5W-30, Extended-Life 5W-30, OE 5W-30, and High-Mileage 5W-30 synthetic motor oils in this viscosity provide outstanding protection against the wear and tear that older engines can experience, helping to maintain horsepower and reduce internal friction.
Moving beyond the engine, the cooling system requires attention to prevent overheating and corrosion. The 1998 Galant’s cooling system has a total capacity of 7.4 quarts. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is an Ethylene Glycol 50/50 pre-mix designed to exceed original equipment manufacturer requirements. This formulation allows for use in a wide variety of vehicles and protects all cooling system metals, gaskets, and hoses. It is phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free, making it compatible with other colors and safe for extended service intervals up to 150,000 miles or five years. For those preferring concentrated solutions, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers even longer protection, extending up to 150,000 miles in passenger cars and light trucks. Both options provide robust protection against metallic corrosion and erosion, ensuring the engine stays within its optimal operating temperature range.
Transmission health is vital for the longevity of the drive system. For the automatic transmission (specifically the F4A23-2 model), the total fill capacity is 6.4 quarts, while an initial fill requires 4.2 quarts. Using a high-performance fluid like AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid ensures the transmission withstands the rigors of heavy towing, elevated temperatures, and challenging terrain. This fluid remains fluid in sub-zero temperatures, providing reserve protection during heavy use. For a more cost-effective option, the AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid guards against leaks and promotes smooth, shudder-free shifts while resisting harmful sludge. If your Galant is equipped with a manual transmission (F5M31-2, 5-speed), the capacity is 4.6 pints. The recommended fluid is a 75W-90 GL-4 AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube. AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube offers outstanding cold-flow properties, protects brass synchronizers, and provides excellent seal compatibility to inhibit rust and corrosion.
Brake system integrity cannot be overlooked. The hydraulic AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid for this vehicle should be DOT 3 compliant. AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid offers excellent responsiveness for ABS and traction-control systems. Its stable viscosity over a wide temperature range ensures consistent braking performance, whether you are in freezing winter conditions or hot summer traffic. The power steering fluid specification for this model calls for DEXRON-II Automatic Transmission Fluid, which can be satisfied by the AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid or AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid mentioned earlier. These fluids provide the necessary lubrication and hydraulic properties to keep the power steering system operating smoothly.
Beyond essential fluids, adding fuel system protection can enhance engine performance and efficiency. The AMSOIL P.i.® Performance Improver Gasoline Additive is a powerful tool for maintaining engine health. It restores up to 14% horsepower and brings GDI fuel injectors back to 100% flow rate after just one tank of fuel. This additive helps prevent carbon buildup, reduces the need for higher-octane fuel, and controls pre-ignition knock. Additionally, the AMSOIL Upper Cylinder Lubricant Corrosion Inhibitor lubricates the fuel system and upper cylinders, ensuring compatibility with capless fuel systems and providing an extra layer of protection against wear.
For long-term storage, the AMSOIL Gasoline Stabilizer helps keep fuel fresh up to 12 months, protecting against varnish and gum buildup. The AMSOIL Engine Fogging Oil is a highly-effective rust preventive designed to protect internal engine components during storage or long periods of inactivity. For cleaning, the AMSOIL Brake and Parts Cleaner quickly removes oil, grease, and brake fluid. To protect paint and trim, use the AMSOIL Silicone Spray, AMSOIL Exterior Ceramic Spray, and AMSOIL Interior Detailer – Light Lemon or AMSOIL Interior Detailer – Scent Free. For heavy-duty cleaning, the AMSOIL Heavy-Duty Degreaser dissolves oil and grime, while the AMSOIL Engine Degreaser tackles tough grime on engine surfaces. The AMSOIL Power Foam® Carburetor and Induction-System Cleaner cleans deposits from ethanol and degraded fuel. General cleaning needs can be met with the AMSOIL High-Foam Car Shampoo, AMSOIL Miracle Wash Waterless Wash and Wax Spray, and AMSOIL Glass Cleaner. For corrosion protection, use the AMSOIL Heavy-Duty Metal Protector, AMSOIL MP Metal Protector, and AMSOIL Mudslinger® Mud and Dirt Repellent. For general lubrication, the AMSOIL Synthetic Multi-Purpose Grease is ideal.
Vehicle Background
The 1998 Mitsubishi Galant represents a significant era for the manufacturer, standing as a robust and reliable mid-size sedan that carved out a dedicated niche in the North American market. Part of the sixth generation of the Galant lineup, this model is often appreciated by enthusiasts for its durable engineering and straightforward mechanical layout. Under the hood, the 2.4-liter inline-four engine (4G64 G) serves as the workhorse of the sedan, delivering a balanced mix of torque and efficiency that made it a popular choice for both family transportation and daily commuting.
This vehicle was designed with longevity in mind, featuring a reputation for solid build quality that allowed it to accumulate high mileage on the roads. While it is naturally aspirated in the base 2.4L configuration, the engine design shares lineage with the performance-oriented engines found in other Mitsubishi vehicles, hinting at a capability that owners can tap into with the right maintenance. The Galant’s ride quality is generally characterized by a comfortable, soft suspension setup typical of American-oriented sedans of the late 1990s, making it an easy companion for long highway drives. It remains a favorite among budget-conscious car owners who prioritize dependability and repairability over luxury features, offering a practical solution that remains affordable to maintain even decades after its original release.