🏷️ Basic Information

Make:

Audi

Model:

100

Year:

1991

Chassis Code:

C3-44

👋 Introduction

Positioning:

The 1991 Audi 100 represented Audi's upscale offering in the executive sedan segment, competing with established European and American luxury brands.

Competitors:

Competed with vehicles such as the BMW 5 Series, Mercedes-Benz E-Class, and Volvo 240/740.

Aerodynamics:

The C3 platform was renowned for its advanced aerodynamics, contributing to fuel efficiency and reduced wind noise.

Quattro AWD:

Availability of the iconic Quattro all-wheel-drive system, a hallmark of Audi's performance and handling capabilities.

Interior Design:

Focus on high-quality materials, ergonomic design, and comfortable seating for a premium feel.

📋 Manual Details

Coverage Scope:

All models and all repairs A-Z

Estimated Page Count:

800+

Type:

Service and Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine:

Detailed diagnostic, repair, and overhaul procedures for gasoline engines, including fuel injection systems (KE-Jetronic), ignition systems, emissions control, cooling, and lubrication.

Transmission:

Comprehensive coverage of manual and automatic transmissions, including clutch operation, gear shifting mechanisms, torque converter systems, transmission fluid maintenance, and internal component repair.

Brakes:

In-depth information on hydraulic brake systems, ABS (Anti-lock Braking System) diagnosis and repair, parking brake systems, brake fluid specifications, and component replacement (master cylinder, calipers, rotors).

Suspension Steering:

Detailed procedures for front and rear suspension components (struts, shocks, control arms, bushings), steering system diagnosis and repair (power steering pump, rack and pinion), wheel alignment specifications.

Electrical Electronics:

Extensive coverage of the vehicle's electrical system, including wiring diagrams, battery, starting system, charging system (alternator), lighting, instrumentation, power windows, central locking, and electronic control units (ECUs).

Climate Control:

Diagnosis and repair of HVAC (Heating, Ventilation, and Air Conditioning) systems, including refrigerant handling, compressor service, blower motor, and climate control panel operations.

Body Chassis:

Information on body panel repair, door mechanisms, interior trim removal and installation, glass replacement, and chassis component maintenance.

Maintenance:

Regular service intervals, oil change procedures, filter replacements (oil, air, fuel), spark plug service, coolant flushes, brake inspections, and general preventative maintenance tasks.

Diagnostics:

Systematic troubleshooting guides, symptom-based diagnostics, fault code interpretation (where applicable), and diagnostic test procedures for all major systems.

Repair:

Step-by-step instructions for component removal, installation, and overhaul for all major mechanical and electrical systems.

Torque Specifications:

Detailed torque specifications for all critical fasteners, bolts, and nuts across various vehicle systems.

Wiring Diagrams:

Comprehensive and detailed electrical wiring diagrams for all vehicle circuits.

Depth:

Complete factory-level repair and diagnostic information, suitable for professional technicians and advanced DIY enthusiasts.

📊 Manual Specifications

File Type:

PDF

Quality:

High-resolution, searchable text and clear diagrams for easy navigation and printing.

Binding:

N/A (Digital Download)

Paper Quality:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Code:

Various, common include 2.3L 5-cylinder (NG, NF)

Engine Type:

Inline 5-cylinder, 20-valve (typically)

Displacement:

2309 cc (2.3 Liters)

Horsepower:

Approximately 130-136 hp @ 5600 rpm (depending on specific engine variant and market)

Torque:

Approximately 140-145 lb-ft @ 3000-3500 rpm (depending on specific engine variant and market)

Fuel Injection:

Bosch KE-Jetronic CIS-E (Continuous Injection System - Electronic)

Fuel Type:

Unleaded Gasoline

Coolant Type:

Ethylene Glycol based coolant (e.g., G11 specification)

Oil Capacity:

Approximately 4.5 - 5.0 liters (with filter change, depending on engine variant)

Recommended Oil Viscosity:

10W-40 or 15W-40 (refer to manual for specific ambient temperature ranges)

🔧 Transmission

Type:

5-speed Manual Transmission

Type:

4-speed Automatic Transmission (e.g., ZF 4HP22)

AWD System:

Optional Quattro permanent all-wheel drive system available with both manual and automatic transmissions.

Atf Type:

Dexron III or equivalent (check manual for exact specification)

Gear Oil Type:

API GL-4 SAE 75W-90 or SAE 80W-90 (check manual for specific axle/transmission type)

📐 Dimensions

Length:

Approximately 4780 mm (188.2 inches)

Width:

Approximately 1770 mm (69.7 inches)

Height:

Approximately 1420 mm (55.9 inches)

Wheelbase:

Approximately 2687 mm (105.8 inches)

Curb Weight:

Approximately 1350 - 1550 kg (2976 - 3417 lbs) depending on configuration

Gross Vehicle Weight:

Varies by model/engine, refer to VIN plate

Wheel Bolt Pattern:

5x112mm

Standard Tire Size:

Typically 195/65R15 or 205/60R15 (check specific model)

🛡️ Safety Features

Crash Test Data:

Limited standardized crash test data from this era compared to modern standards. Audi emphasized safety through its 'Procon-ten' system.

ABS:

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

AWD:

Quattro all-wheel-drive system offered significant improvements in traction and stability.

Airbags:

Driver's airbag typically optional or standard on higher trims; passenger airbag was less common.

Seatbelts:

Front and rear seat belts, with front seat belt pretensioners often standard.

Procon Ten:

Audi's proprietary 'Procon-ten' passive safety system, which tightened seatbelts and moved the steering wheel forward in a frontal collision.

💡 Technology Features

Audio System:

Factory-installed AM/FM stereo with cassette player, often with premium speaker options.

Climate Control Tech:

Manual or optional automatic climate control systems.

Cruise Control:

Standard or optional cruise control system.

Early Tech:

While not featuring modern connectivity, the C3 platform represented advanced automotive technology for its time, particularly with Quattro and aerodynamic design.

🔧 Maintenance

Oil Change:

Typically every 7,500 - 10,000 miles (12,000 - 15,000 km) or 12 months, whichever comes first, depending on driving conditions.

Timing Belt:

Crucial maintenance item. Typically recommended replacement every 60,000 miles (96,000 km) or 4-5 years for 5-cylinder engines.

Spark Plugs:

Replacement at intervals of approximately 30,000 miles (48,000 km).

Coolant Capacity:

Approximately 7.0 - 7.5 liters (depending on engine variant)

Brake Fluid Type:

DOT 3 or DOT 4 (check manual for precise specification)

Wiring Harness:

Degradation of wire insulation, particularly in engine bay and door jambs, leading to electrical gremlins.

Fuel Distribution Head:

Potential issues with the KE-Jetronic fuel distributor head requiring specialized diagnosis and repair.

Cooling System:

Leaks from hoses, radiator, and water pump are common due to age; thermostat housing can also be a source of leaks.

Suspension Components:

Wear in control arm bushings, ball joints, and tie rod ends can affect handling and steering feel.

Oil Leaks:

Common oil leaks from valve cover gaskets, oil pan gaskets, and the rear main seal.

Timing Belt Replacement:

Critical preventative maintenance due to interference engine design.

ABS Sensor Replacement:

ABS wheel speed sensors can fail, leading to ABS warning lights.

📚 Vehicle History

Origin:

Audi AG, a German automobile manufacturer, known for its engineering and the pioneering Quattro all-wheel-drive system.

C3 Generation:

The C3 generation of the Audi 100 (Type 44) was produced from 1982 to 1991. The 1991 model year is the final iteration of this generation.

Manufacturing Location:

Ingolstadt, Germany (primary)

Lifespan:

The Audi 100 nameplate was used from 1968 to 1994 before being rebranded as the Audi A6.

🏆 Awards & Recognition

Design Awards:

The C3 platform was noted for its advanced aerodynamic design, often cited in automotive design discussions of the era.

Reliability Perception:

While generally well-built, specific components and the complex KE-Jetronic system can require diligent maintenance to maintain reliability.