🏷️ Basic Information

Make:

Mazda

Model:

RX-4

Year:

1973

👋 Introduction

Market Positioning:

The 1973 Mazda RX-4 represented Mazda's continued commitment to rotary engine technology in the compact and mid-size car segments. It competed against a range of Japanese and American vehicles, offering unique performance characteristics derived from its Wankel engine.

Key Competitors:

Datsun (Nissan) 510, Toyota Corona, Ford Pinto, Chevrolet Vega, AMC Gremlin

Unique Selling Points:

Smooth rotary engine operation, distinctive styling, good power-to-weight ratio for its class, innovative technology for the era.

📋 Manual Details

All Models Covered:

True

All Repairs A Z:

True

Estimated Page Count:

Approximately 400-600 pages (typical for comprehensive factory service manuals of this era)

Manual Type:

Factory Service Manual / Repair Manual

Language:

English

Format:

Printed Manual (Original or High-Quality Reproduction)

📖 Manual Coverage

Engine:

Rotary Engine (12A) - Theory of Operation, Disassembly, Assembly, Inspection, Lubrication, Cooling, Ignition, Fuel System, Emissions Control

Transmission:

Manual Transmission (4-speed, 5-speed) and Automatic Transmission (3-speed) - Overhaul, Adjustments, Driveline Components

Brakes:

Front Disc Brakes, Rear Drum Brakes - Inspection, Service, Hydraulic System, Adjustment, Bleeding

Suspension:

Front Independent Suspension (MacPherson Strut), Rear Leaf Spring Suspension - Component Inspection, Bushing Replacement, Shock Absorber Service, Alignment Specifications

Steering:

Recirculating Ball Steering System - Inspection, Adjustment, Tie Rod End Service, Steering Column

Electrical:

Starting System, Charging System (Alternator), Ignition System, Lighting System, Instrumentation, Wiring Diagrams, Fuses, Relays, Switches, Power Accessories

Fuel System:

Carburetion (Hitachi/Nikki Twin-Choke), Fuel Pump, Fuel Lines, Fuel Tank - Cleaning, Adjustment, Jetting, Troubleshooting

Cooling System:

Water-Cooled Rotary Engine, Radiator, Fan, Thermostat, Hoses - Flush, Antifreeze Specifications, Component Replacement

Exhaust System:

Exhaust Manifold, Pipes, Muffler - Inspection, Gasket Replacement

Body And Interior:

Body Panel Repair, Door Mechanisms, Window Regulators, Seat Adjustments, Interior Trim, Upholstery

Routine Maintenance:

Oil Changes, Filter Replacements, Spark Plug Service, Fluid Level Checks, Tire Rotation

Troubleshooting:

Diagnostic Charts, Symptom-Based Troubleshooting Guides, Component Testing Procedures

Engine Overhaul:

Apex Seal Replacement, Rotor Housing Inspection, Eccentric Shaft Service, Seal Kit Installation

Transmission Rebuild:

Gear Disassembly, Bearing Replacement, Synchro Ring Service, Clutch Assembly (Manual Transmission)

Brake Service:

Pad/Shoe Replacement, Rotor/Drum Machining, Caliper/Wheel Cylinder Rebuild, Bleeding Procedure

Electrical Diagnostics:

Wiring Diagram Interpretation, Voltage Drop Testing, Component Testing (Starter, Alternator, Ignition Coil)

Carburetor Adjustment:

Idle Speed, Air-Fuel Mixture, Float Level Adjustment

Tune Up Procedures:

Ignition Timing, Spark Plug Gap, Carburetor Settings

Wheel Alignment:

Camber, Caster, Toe-in Specifications and Adjustment Procedures

Depth Of Coverage:

Comprehensive, technician-level detail covering diagnostics, repair, overhaul, and adjustment for all major vehicle systems.

📊 Manual Specifications

File Format:

Typically printed paper, but digital versions (PDF) are also common for resale. High resolution and searchable text are key for digital.

Print Quality:

Original manuals are often black and white with clear line drawings and diagrams. High-quality reproductions maintain clarity.

Binding Type:

Stapled, perfect bound, or hardcover for professional manuals. Spiral binding is also common for ease of use.

Paper Type:

Durable, semi-gloss paper suitable for workshop environments.

⚙️ Engine Specifications

Engine Type:

Rotary (Wankel)

Engine Code:

12A

Engine Configuration:

Two-Rotor, Naturally Aspirated

Displacement:

1146 cc (approx. 69.9 cubic inches) - Note: Rotary displacement is often calculated differently than piston engines.

Horsepower:

Approximately 100-110 hp (SAE Gross) depending on specific market and emissions equipment.

Torque:

Approximately 110-120 lb-ft (SAE Gross)

Carburetor:

Hitachi (or Nikki) Twin-Choke Downdraft Carburetor

Fuel Type:

Unleaded Gasoline (though leaded gasoline was still common in 1973, early unleaded compatibility is a consideration)

Ignition Type:

Distributor-based, Single Ignition Coil

Oil Type:

API SF or SG rated, SAE 10W-30 or 10W-40 (refer to manual for exact specifications and potential specific rotary oil requirements)

Cooling Type:

Water-cooled

🔧 Transmission

Standard Transmission:

4-speed Manual Transmission

Optional Transmission:

3-speed Automatic Transmission

Clutch Type:

Single Dry Plate Clutch (Manual Transmission)

Transmission Fluid Type:

GL-4 Hypoid Gear Oil (Manual), Dexron III or equivalent (Automatic - verify specific spec in manual)

Driveshaft Type:

Single-piece driveshaft with universal joints.

📐 Dimensions

Wheelbase:

Approx. 98.4 inches (2500 mm)

Length:

Approx. 169.3 inches (4300 mm)

Width:

Approx. 65.0 inches (1651 mm)

Height:

Approx. 53.1 inches (1350 mm)

Curb Weight:

Approx. 2300 - 2500 lbs (1043 - 1134 kg), varies by body style and equipment.

Standard Tire Size:

Typically 175 SR 13 or similar radial tires (confirm with manual)

Wheel Bolt Pattern:

4 x 110 mm (common for Mazda of this era)

🛡️ Safety Features

Safety Ratings:

NHTSA or IIHS ratings for this era are not directly comparable to modern standards. Focus is on passive safety features of the time.

Braking System:

Front Disc Brakes, Rear Drum Brakes

Seatbelts:

Standard lap belts, potential for optional shoulder belts.

Body Construction:

Unibody construction with crumple zones (early design).

💡 Technology Features

Infotainment System:

Basic AM/FM radio, possibly with an 8-track player option. No advanced infotainment features.

Driver Assistance Features:

None. Features like ABS, traction control, or airbags were not standard or available.

Connectivity Features:

No electronic connectivity features.

🔧 Maintenance

Oil Change Interval:

Typically every 3,000 miles or 3 months (refer to manual for specific recommendations based on driving conditions).

Spark Plug Replacement:

Recommended every 15,000 - 20,000 miles. Specific rotary plugs may have different recommendations.

Coolant Flush:

Typically every 2 years or 24,000 miles.

Coolant Type:

Ethylene Glycol based, 50/50 mix with distilled water. Check manual for specific OAT/IAT type if applicable.

Brake Fluid Type:

DOT 3 or DOT 4 (refer to manual for exact specification)

Engine Oil Capacity:

Approx. 4.5-5.0 US quarts (with filter) - Note: Rotary engines may have slightly different oil consumption characteristics. Check manual for specific oil injection requirements if applicable.

Coolant Capacity:

Approx. 6.0-7.0 US quarts (refer to manual for specific capacity)

Transmission Oil Capacity Manual:

Approx. 1.5-2.0 US quarts (refer to manual)

Transmission Oil Capacity Automatic:

Approx. 6.0-7.0 US quarts (refer to manual)

Apex Seal Wear:

Apex seals are a wear item in rotary engines. Premature wear can lead to loss of compression, poor starting, and reduced power. Regular oil changes and proper engine warm-up are crucial.

Carburetor Issues:

Carburetors can become clogged or maladjusted over time, leading to rough idling, poor fuel economy, or difficult starting.

Ignition System Reliability:

Early ignition systems can be prone to component failure (coil, points, condenser). Proper timing and clean contacts are essential.

Cooling System Maintenance:

Maintaining the cooling system is critical for rotary engines to prevent overheating, which can accelerate seal wear. Flush and replace coolant regularly.

📚 Vehicle History

Mazda Rotary Pioneering:

Mazda was a pioneer in the commercialization of the Wankel rotary engine, beginning with the Mazda Cosmo Sport 110S in 1967. The RX-4 was a significant step in establishing the rotary engine's viability in mainstream automotive applications.

Rotary Lineup:

The RX-4 followed the RX-2 and preceded the RX-7, forming part of Mazda's dedicated rotary sports and performance car lineage.

Production Years:

1972-1978 (RX-4)

Body Styles:

Coupe, Sedan, Wagon

🏆 Awards & Recognition

Rotary Engine Recognition:

Mazda's rotary engine technology itself received significant recognition for its innovation and performance characteristics, leading to motorsport success and a dedicated following.