The 1981 Honda Civic with the 1.5L 4-cylinder EM1 M engine represents a classic era of automotive engineering where simplicity and reliability were paramount. However, even the most durable mechanical designs require consistent lubrication to maintain peak performance over decades of service. Proper fluid selection ensures that critical components like the flat-tappet camshafts, the three-speed automatic transmission, and the cooling system continue to operate smoothly. Using the correct viscosities and specifications helps resist wear, manage thermal loads, and prevent the sludge buildup that can plague older engines. Below are the specific AMSOIL lubricants recommended to keep this vintage Honda running as effectively as it did when it rolled off the assembly line.
Recommended AMSOIL Products
- AMSOIL Premium Protection 10W-40 100% Synthetic Motor Oil – A high-zinc formula specifically designed to guard against wear on flat-tappet cams, making it ideal for this vintage engine.
- AMSOIL Extended-Life 10W-40 100% Synthetic Motor Oil – Provides superior cleaning power and extended protection for 20,000 miles between changes to keep the engine running smoothly.
- WIX Oil Filter – Features premium media that offers improvements over original equipment manufacturer-branded filters to ensure proper oil circulation.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – An ethylene glycol-based 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated coolant solution requiring mixing, offering protection for up to 150,000 miles or 5 years in passenger cars.
- AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy use and elevated temperatures, remaining fluid even in sub-zero conditions.
- AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid – Designed to promote smooth, shudder-free shifts while guarding against leaks and sludge buildup.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Provides a stable viscosity over a wide temperature range with excellent responsiveness for ABS and traction-control systems.
For the engine, the 1981 Honda Civic with the EM1 M engine requires a specific oil capacity of 3.7 quarts when the filter is changed. It is crucial to check the oil level after refilling to ensure it does not exceed the safe operating range. For temperatures above -20°C, a 10W-40 viscosity is recommended, while 10W-30 is suitable for colder conditions. The drain plug should be torqued to 33 ft/lbs during service. The AMSOIL Premium Protection 10W-40 is particularly beneficial for this vehicle due to its high zinc content, which is necessary for protecting older flat-tappet camshafts found in many 1980s Japanese engines. Alternatively, the AMSOIL Extended-Life 10W-40 offers a balance of cleaning power and durability, allowing for longer service intervals if desired.
Moving to the cooling system, the 1981 Honda Civic requires a total capacity of 5.8 quarts of antifreeze. The standard recommendation is an ethylene glycol-based fluid that prevents corrosion and protects rubber hoses. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a 50/50 pre-mix that meets or exceeds OEM requirements. It is free of phosphates, nitrates, and silicates, making it safe for the specific metals used in the cooling systems of that era. For those who prefer to mix their own AMSOIL Propylene Glycol Antifreeze and Engine Coolant, it is an excellent option. It offers extended life protection and is compatible with all other coolant colors, ensuring you can mix top-offs without causing chemical conflicts within the radiator or heater core.
Transmission and Manual Gear Lubrication
The transmission maintenance for this model varies depending on whether the vehicle has a 3-speed automatic or a manual unit. For the 3-speed automatic transmission, the total fill capacity is 5.2 quarts, with an initial fill of 2.6 quarts. The fluid requirement specifies the AM-3 or AF2 specification. AMSOIL offers the AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid for the most robust protection, capable of withstanding heavy towing and elevated temperatures. This fluid remains fluid in sub-zero temperatures and provides reserve protection during heavy use. For those looking for a slightly more economical option that still provides high-level protection, the AMSOIL OE Multi-Vehicle 100% Synthetic Automatic Transmission Fluid is a strong candidate. It is engineered to resist harmful sludge and promotes shudder-free shifts, which is vital for the longevity of the transmission.
If the vehicle is equipped with a manual transmission, the requirements change. The capacity for the manual transmission is 5.3 pints. The drain plug should be torqued to 29 ft/lbs, and the fill plug to 51 ft/lbs. For manual transmissions, the recommendation allows for 10W-30 or 10W-40 viscosity oils, provided they meet the U/K or SJ specifications for all temperatures. In this scenario, AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil or AMSOIL Extended-Life 10W-30 100% Synthetic Motor Oil can be used effectively. These engine oils provide excellent shear stability and protection for the synchronizers and gears, ensuring smooth shifting in the gearbox.
The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is critical for maintaining safety standards. The vehicle requires a Honda Heavy Duty Brake Fluid DOT 3 specification. AMSOIL offers a synthetic brake fluid that meets and exceeds both DOT 3 and DOT 4 standards. This fluid provides a stable viscosity over a wide temperature range, ensuring consistent pedal feel. It offers excellent responsiveness for ABS and traction-control systems, even if aftermarket upgrades have been made. The synthetic formulation resists boiling and moisture absorption better than conventional fluids, which helps prevent brake fade and corrosion within the master cylinder and wheel cylinders.
About the Vehicle
The 1981 Honda Civic belongs to the second generation of the Civic lineup, known widely as the “EG” series or the third generation in some markets, but typically recognized by its compact, boxy, and efficient design. Released during the early 1980s, this era of the Civic was defined by its contribution to the oil crisis response, prioritizing fuel economy and reliability over raw power. The 1.5L 4-cylinder EM1 M engine was a workhorse, renowned for its smooth operation and durability. It produced modest horsepower, typically ranging between 60 and 80 horsepower depending on the specific market and transmission type, but it delivered this power with a level of refinement that set it apart from competitors of the time.
Owners of this vehicle often prize the 1981 Civic for its simplicity. The mechanical nature of the engine and transmission makes it an ideal candidate for do-it-yourself maintenance, allowing enthusiasts to easily access and replace components. The car was offered primarily as a sedan or hatchback and later as a coupe, becoming a staple in the economy car segment. Its reputation for longevity is legendary, with many examples still on the road today. The driving character is generally described as light, agile, and responsive, making it well-suited for city commuting. The suspension geometry was tuned for comfort, offering a compliant ride that absorbed road imperfections well. This specific model year sits at a transitional point in Honda’s history, showcasing the brand’s commitment to engineering excellence that would later dominate the global auto market.
Additional Maintenance and Storage
To ensure the vehicle remains in top condition, especially during periods of storage, specialized additives can be beneficial. The AMSOIL Gasoline Stabilizer is recommended for seasonal storage, helping to keep fuel fresh for up to 12 months. It fights ethanol corrosion and prevents the varnish and gum buildup that can clog the carburetors or fuel injectors of older Honda engines. For longer periods of inactivity, AMSOIL Engine Fogging Oil can be used to protect internal engine components from rust by coating cylinder walls and other critical areas. This is particularly useful for vehicles that are kept as collectors’ items or used seasonally.
For those interested in performance improvement, AMSOIL P.i. Performance Improver Gasoline Additive can be used to restore up to 14% horsepower and clean GDI fuel injectors. This additive helps remove carbon deposits that can accumulate over time, improving fuel economy and reducing the need for higher-octane fuel. Additionally, the AMSOIL Upper Cylinder Lubricant Corrosion Inhibitor can be used to lubricate the fuel system and upper cylinders, ensuring that the engine runs smoothly and quietly. These additives, when used in conjunction with the recommended lubricants, help preserve the integrity of the engine and maximize its performance potential.
Finally, for general vehicle care, AMSOIL offers a range of cleaning and protective products. The AMSOIL Miracle Wash Waterless Wash and Wax Spray is a convenient option for regular cleaning, leaving a protective finish that repels dust and dirt. For undercarriage protection, the AMSOIL Heavy-Duty Metal Protector or AMSOIL Silicone Spray can be used to shield components from rust and corrosion, especially in areas exposed to salt or moisture. These products ensure that the vehicle not only runs well but also looks its best, maintaining its classic appeal for years to come.