🏷️ Basic Information

Make:

Mitsubishi

Model:

Diamante

Generation:

First Generation (JDM: Sigma)

Production Years Covered:

1990-1995

Market Segment:

Full-size Luxury Sedan / Hardtop Sedan

Chassis Codes:

F11A, F12A, F13A, F15A, F17A, F25A, F27A, F31A, F36A

👋 Introduction

Market Positioning:

The Mitsubishi Diamante (and its JDM counterpart, the Sigma) was positioned as a premium, technologically advanced full-size sedan, competing with established luxury marques in its era. It aimed to offer a blend of performance, comfort, and distinctive styling.

Key Competitors:

Competed against vehicles like the Toyota Avalon, Lexus ES, Infiniti J30, Acura Legend, and some European luxury sedans in its segment.

Unique Selling Points:

Available with potent V6 engines, advanced (for its time) multi-link suspension, optional all-wheel-drive (on some models), and a focus on a quiet and refined ride. Known for distinctive 'cab-forward' styling.

Manual Value:

Provides factory-level repair and maintenance information, enabling owners and independent mechanics to perform tasks accurately and efficiently, saving significant costs compared to dealership service.

📋 Manual Details

Manual Coverage:

Comprehensive service, repair, diagnosis, and troubleshooting for all major systems.

Estimated Page Count:

Thousands of pages (typical for comprehensive workshop manuals of this era)

Manual Type:

Factory Service Manual / Workshop Manual

Language:

English

Digital Format:

PDF Download

📖 Manual Coverage

Engine Mechanical:

Engine assembly, cylinder head, crankshaft, pistons, connecting rods, timing belt/chain, lubrication system, cooling system.

Engine Electrical:

Ignition system, starting system, charging system, sensors, actuators, engine control unit (ECU).

Emission Control:

Catalytic converter, EGR system, EVAP system, oxygen sensors, emission control modules.

Fuel System:

Fuel tank, fuel pump, fuel lines, fuel injectors, fuel pressure regulator, throttle body.

Clutch System:

Clutch disc, pressure plate, release bearing, clutch hydraulics (master and slave cylinders).

Manual Transaxle:

Gearbox assembly, gear selection, clutch operation, internal components, lubrication.

Automatic Transaxle:

Torque converter, transmission control unit (TCU), hydraulic control system, planetary gear sets, valve body.

Driveshaft And Axle:

Driveshafts, CV joints, differential, hub assemblies.

Suspension System:

MacPherson struts, multi-link rear suspension, control arms, ball joints, shock absorbers, springs, bushings.

Steering System:

Power steering pump, steering rack/gearbox, tie rods, steering column, wheel alignment specifications.

Restraint System:

Seat belts (pre-tensioners if applicable), airbags (SRS system diagnosis and components).

Brake System:

Disc brakes (front and rear), ABS system (if equipped), brake fluid specifications, hydraulic lines, parking brake.

Body Interior Exterior:

Body panel removal and installation, door mechanisms, glass, trim, interior components, sound deadening.

Body Electrical:

Lighting system (headlights, taillights, interior), power windows, power locks, mirrors, wipers, horn, infotainment wiring.

HVAC System:

Air conditioning system, heater core, blower motor, climate control unit, refrigerant type and capacity.

Maintenance:

Scheduled maintenance (oil changes, filter replacements, spark plugs, fluid checks), lubrication points, tune-up procedures.

Troubleshooting:

Diagnostic charts, symptom-based troubleshooting, electrical diagnostic procedures, common problem diagnosis.

Repair:

Step-by-step repair instructions for all major components and systems, including disassembly and reassembly.

Diagnostics:

OBD-I (On-Board Diagnostics) information where applicable, diagnostic trouble codes (DTCs), sensor data interpretation.

Technical Depth:

Comprehensive; covers everything from basic maintenance to in-depth engine and transmission rebuilds, electrical system diagnosis, and body repairs.

📊 Manual Specifications

File Format Details:

Adobe PDF; searchable text, zoomable diagrams and illustrations.

Print Quality:

High-resolution scans ensuring clarity of text and diagrams; printable pages.

Binding Type:

N/A (Digital Format)

Paper Type:

N/A (Digital Format)

⚙️ Engine Specifications

Engine Options:

3.0L V6 SOHC (6G72), 3.5L V6 SOHC (6G73), 3.5L V6 DOHC (6G73) - exact availability varies by year and market.

Horsepower Range:

Approximately 150-210 HP depending on engine and configuration.

Torque Range:

Approximately 180-230 lb-ft depending on engine and configuration.

Fuel Delivery:

Electronic Fuel Injection (EFI)

Timing Drive:

Timing Belt (for most V6 engines in this generation)

🔧 Transmission

Standard Transmission:

4-Speed Automatic Transmission (FWD and AWD)

Optional Transmission:

5-Speed Manual Transaxle (less common, primarily on some FWD models)

Transmission Features:

Sportronic (sequential shifting on some automatic transmissions), Electronic Control Unit (ECU) managed shift points.

📐 Dimensions

Wheelbase:

Approximately 110.4 inches (2804 mm)

Overall Length:

Approximately 195.9 inches (4976 mm)

Curb Weight:

Approximately 3,500 - 4,000 lbs (1588 - 1814 kg) depending on configuration.

🛡️ Safety Features

Crash Test Data:

Limited standardized crash test data available for this specific era and market. Refer to specific regulatory body archives if available.

Active Safety Features:

Anti-lock Braking System (ABS) - optional on many models.

Passive Safety Features:

Driver and passenger front airbags (SRS), front and rear crumple zones, side-impact door beams.

💡 Technology Features

Infotainment Features:

Cassette player, AM/FM radio, optional CD player, basic digital climate control displays.

Driver Assistance Features:

Cruise control, optional ABS.

Connectivity Options:

Limited by modern standards; primarily analog systems. Antennas for radio reception.

🔧 Maintenance

Oil Change Interval:

Typically every 3,750 to 7,500 miles (6,000 to 12,000 km) or 6 months, depending on driving conditions and oil type used. Refer to manual for specific recommendations.

Timing Belt Replacement:

Critical: 60,000 to 90,000 miles (96,000 to 145,000 km) for the 6G72/6G73 engines. Failure can cause catastrophic engine damage. Manual will specify the exact interval and procedures.

Engine Oil Spec:

API SG or higher, SAE 10W-30 or 10W-40. Consult manual for exact viscosity based on climate.

Transmission Fluid Auto:

MITSUBISHI DIA QUEEN ATF-II E or equivalent DEXRON II (or compatible) is commonly specified. Check manual for exact specification.

Brake Fluid Spec:

DOT 3 or DOT 4 brake fluid.

Coolant Spec:

Ethylene glycol-based coolant, typically a 50/50 mix with distilled water. Refer to manual for specific Mopar or equivalent coolant type.

Common Issues:

Timing belt failure (if not replaced on schedule), transmission solenoid issues, power window regulators, CV joint wear, suspension bushing deterioration, potential head gasket issues on some engine variants (though less common than some contemporaries).

📚 Vehicle History

Brand Heritage Context:

Mitsubishi's history in producing reliable and technologically innovative vehicles, including luxury and performance models.

First Generation Overview:

Launched globally, the Diamante represented Mitsubishi's ambition to compete in the larger, more luxurious sedan segment. It was characterized by its distinctive styling and was available in various configurations, including front-wheel drive and all-wheel drive. In Japan, it was also sold as the Mitsubishi Sigma. The 'Diamante' name signifies 'diamond' in Portuguese and Spanish, reflecting Mitsubishi's corporate logo.

Manufacturing Locations:

Primarily manufactured in Japan.

🏆 Awards & Recognition

Industry Recognitions:

While specific awards are not widely publicized for this model, it was recognized for its advanced styling and engineering for its time within its class.