🏷️ Basic Information

Make:

Subaru

Model:

Impreza

Year:

1998

Chassis Code:

GC8 (Coupe/Sedan), GF8 (Wagon)

Engine Codes:

EJ22 (2.2L NA), EJ25D (2.5L NA SOHC), EJ20G (2.0L Turbo DOHC - WRX/STI variants), EJ20K (2.0L Turbo DOHC - WRX/STI variants)

👋 Introduction

Segment:

Compact/Small Family Car, known for its performance-oriented AWD variants (WRX).

Niche:

Often appealed to enthusiasts and those seeking all-weather capability or rally-inspired performance.

Competitors 1998:

Honda Civic, Toyota Corolla, Mitsubishi Lancer, Mazda Protege, Ford Focus.

Competitive Advantage:

Standard Symmetrical AWD across most trims, spirited driving dynamics, especially in WRX models.

All Wheel Drive:

Standard Symmetrical All-Wheel Drive provided superior traction and handling in varied conditions.

Engine Options:

A range of boxer engines, including reliable naturally aspirated units and potent turbocharged engines for performance models.

Body Styles:

Available as a 2-door coupe, 4-door sedan, and 5-door wagon, offering versatility.

Performance Variants:

The iconic Impreza WRX (and its limited production STI variant) offered turbocharged performance and a distinct rally heritage.

📋 Manual Details

Engine:

Covers 2.2L Naturally Aspirated (EJ22), 2.5L Naturally Aspirated SOHC (EJ25D), and various 2.0L Turbocharged DOHC (EJ20G, EJ20K) variants found in WRX and STI models of the era.

Transmission:

Includes details for 5-speed manual and 4-speed automatic transmissions.

Drivetrain:

Detailed information on Subaru's Symmetrical All-Wheel Drive (AWD) system, including viscous couplings and differentials.

Chassis:

Suspension (front struts, rear multi-link), steering, braking system (front discs, rear discs/drums depending on model), wheel alignment.

Body:

Body panel repair, door mechanisms, glass replacement, interior trim removal and installation, exterior trim.

Electrical:

Wiring diagrams, diagnostic procedures for lighting, power accessories, instrument cluster, ECU, sensors, and related systems.

HVAC:

Air conditioning system service, heater core replacement, blower motor, climate control system.

Diagnostics:

Troubleshooting guides, symptom-based diagnostics, OBD-II connector and diagnostic trouble codes (DTCs).

Estimated Pages:

1000+

Type:

Factory Service Manual (FSM) / Repair Manual

Language:

English

Format:

Likely a comprehensive printed book or a digital PDF.

📖 Manual Coverage

Engine Mechanical:

Engine disassembly, assembly, cylinder head, pistons, crankshaft, camshafts, timing belt/chain replacement, lubrication system, cooling system.

Engine Performance:

Fuel injection system (EFI), ignition system, emissions control systems (catalytic converter, EGR), turbocharger operation and service (for turbo variants).

Transmission Manual:

Clutch system, gearbox removal, disassembly, assembly, and adjustment.

Transmission Automatic:

Torque converter, valve body, internal transmission components, fluid service and inspection.

Braking System:

Front and rear brake component replacement (pads, rotors, calipers), bleeding procedure, parking brake adjustment.

Steering System:

Power steering pump, rack and pinion, steering column, tie rod ends, alignment specifications.

Suspension System:

Struts, shocks, control arms, bushings, springs, sway bars, wheel bearing replacement.

Fuel System:

Fuel tank, fuel pump, fuel filter replacement, fuel injectors, pressure regulator.

Cooling System:

Radiator, hoses, thermostat, water pump, coolant specifications and flush procedures.

Exhaust System:

Catalytic converter, mufflers, exhaust pipes, hangers, oxygen sensor replacement.

Electrical Engine Control:

ECU pinouts, sensor testing (MAP, TPS, crank/cam sensors), actuator testing (idle control valve, injectors).

Electrical Body:

Headlights, taillights, interior lighting, power windows, door locks, wipers, horn, instrument cluster diagnostics.

Maintenance:

Oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspection and replacement, brake fluid flush.

Troubleshooting:

Systematic diagnostic flowcharts for common drivability issues, starting problems, electrical faults.

Repair:

Step-by-step instructions for component replacement and repair across all major vehicle systems.

Rebuilds:

Detailed instructions for engine and transmission overhauls/rebuilds, including specifications and tolerances.

Alignment:

Wheel alignment specifications and adjustment procedures.

Diagnostics OBD-Ii:

Guidance on reading and interpreting OBD-II codes and performing basic diagnostic tests.

Depth:

Comprehensive, covering everything from basic preventative maintenance to complete engine and transmission rebuilds, including intricate electrical diagnostics.

📊 Manual Specifications

Digital Format:

PDF (if digital) with searchable text and high-resolution diagrams.

Print Quality:

High-quality printing with clear text and sharp, detailed diagrams and illustrations (if physical).

Binding:

Durable binding, often a hardback or robust paperback, designed for workshop use (if physical).

Paper Type:

Heavy-duty, grease-resistant paper suitable for workshop environments (if physical).

⚙️ Engine Specifications

Engine 2.2L Na:

EJ22 SOHC, 2.2 Liters, 16 valves, approximately 135 hp @ 5600 rpm, 137 lb-ft @ 4400 rpm.

Engine 2.5L Na Sohc:

EJ25D SOHC, 2.5 Liters, 16 valves, approximately 165 hp @ 6000 rpm, 162 lb-ft @ 4000 rpm.

Engine 2.0L Turbo DOHc:

EJ20G/EJ20K DOHC, 2.0 Liters, 16 valves, turbocharged, intercooled. Horsepower varied: WRX typically 210-237 hp, STI higher. Torque also significantly higher.

Redline Na:

Approximately 6000-6500 rpm for naturally aspirated engines.

Redline Turbo:

Approximately 7000-7500 rpm for turbocharged engines (WRX/STI).

Fuel Type:

Unleaded gasoline.

Fuel Delivery:

Electronic Fuel Injection (EFI) with multi-point injectors.

Ignition System:

Distributorless ignition system (D.I.S.) with coil-on-plug or coil pack setup.

ECU:

Engine Control Unit (ECU) manages fuel, ignition, and other engine parameters.

🔧 Transmission

Transmission Standard:

5-speed Manual Transmission.

Transmission Optional:

4-speed Automatic Transmission with overdrive.

AWD System:

Subaru's Symmetrical All-Wheel Drive system, featuring a viscous coupling center differential for mechanical power distribution.

Manual Gears:

Specific gear ratios vary by model and drivetrain, but typically offer a close-ratio setup for sporty driving.

Manual Transmission Fluid:

API GL-5, SAE 75W-90 gear oil is commonly recommended.

Automatic Transmission Fluid:

Subaru Genuine ATF or equivalent Dexron III/Mercon compatible fluid.

📐 Dimensions

Length:

Sedan: ~169.0 inches; Wagon: ~172.0 inches

Width:

~66.7 inches

Height:

Sedan: ~55.1 inches; Wagon: ~55.7 inches

Wheelbase:

~99.9 inches

Curb Weight:

Varies by model and trim, typically 2700-3000 lbs for NA models, 3000-3200 lbs for WRX models.

Gross Vehicle Weight Rating:

Refer to vehicle's door jamb sticker for specific GVWR.

🛡️ Safety Features

NHTSA Frontal Crash:

Tested models generally received good to acceptable ratings in frontal impacts for their era. Specific ratings can be found via NHTSA archives.

IIHS Offset Frontal Crash:

IIHS ratings for this period often showed 'Acceptable' or 'Marginal' performance in offset frontal tests. Subaru improved significantly in later generations.

ABS:

Anti-lock Braking System (ABS) was typically standard or optional depending on trim and model year.

AWD:

Symmetrical All-Wheel Drive inherently provides enhanced traction and stability, acting as a primary safety feature.

Airbags:

Driver and front passenger airbags standard.

Seatbelts:

Three-point seatbelts with pre-tensioners for front occupants.

💡 Technology Features

Audio System:

Factory-installed AM/FM stereo with cassette player, and optional CD player. Speaker configurations varied by trim.

Display:

Basic analog gauges for speedometer, tachometer, fuel, and temperature. Minimal digital displays.

Cruise Control:

Available on most trims, mechanically operated.

Traction Control:

Generally not available on this generation, except possibly on very late or specialized models. AWD served as the primary traction enhancement.

Bluetooth:

Not available. Aftermarket solutions required for Bluetooth connectivity.

Usb:

Not available. Aftermarket solutions required.

🔧 Maintenance

Oil Change Interval:

Typically every 3,750 to 7,500 miles, depending on driving conditions and oil type used. Manual may specify 3,750 miles for severe service.

Timing Belt Replacement:

Crucial interval, typically 60,000 to 105,000 miles or 5-7 years for interference engines (EJ25D, EJ20G/K). EJ22 may have a timing chain or a different interval. Consult manual.

Spark Plug Replacement:

Approximately 30,000 to 60,000 miles, depending on plug type (platinum, iridium).

Coolant Flush:

Every 30,000 miles or 2 years.

Engine Oil:

SAE 5W-30 or 10W-30 API SG or higher. Refer to manual for specific viscosity based on climate.

Coolant:

Subaru Super Coolant (or equivalent) mixed 50/50 with distilled water. Green colored coolant common for this era.

Brake Fluid:

DOT 3 or DOT 4 brake fluid.

Head Gaskets:

The EJ25D engine (2.5L NA SOHC) is notoriously prone to head gasket failure. The manual will detail replacement procedures.

Timing Belt Failure:

Failure to adhere to timing belt replacement intervals can lead to catastrophic engine damage (interference engine).

O2 Sensors:

Premature failure of oxygen sensors can affect fuel economy and emissions.

Clutch Wear:

Manual transmission clutch wear is common with age and driving style.

Rear Main Seal:

Leaking rear main engine seal is a common issue on higher mileage vehicles.

📚 Vehicle History

Subaru Legacy:

Subaru has a long history of producing AWD vehicles, dating back to the Subaru Leone and developing the Symmetrical AWD system.

First Generation Gc8 Gf8:

The 1998 model belongs to the first generation (GC8/GF8) of the Impreza, introduced in 1992 in Japan and 1995 in North America.

Wrx Debut:

The performance-oriented WRX variant debuted in Japan in 1992, quickly gaining a reputation in rally racing.

Facelift 1998:

The 1998 model year often corresponds with a mid-cycle facelift for the first generation, introducing updated styling (e.g., new headlights, bumpers).

Manufacturing Location:

Primarily manufactured in Japan.

🏆 Awards & Recognition

Car And Driver 10Best:

The Impreza WRX models were frequently recognized for their performance and value by automotive publications in subsequent generations, though the 1998 model may have been a precursor to broader acclaim.

Rally Championships:

Subaru Imprezas, particularly the WRX variants, achieved significant success in international rally championships (WRC), enhancing the model's performance image.