🏷️ Basic Information

Make:

Porsche

Model:

928 S4

Years Covered:

1987, 1988, 1989, 1990, 1991

👋 Introduction

Market Position:

The Porsche 928 S4 was a luxurious, high-performance grand tourer, positioned as a unique alternative to traditional front-engined sports cars.

Competitive Analysis:

Competed with other luxury GT cars of its era, such as the Jaguar XJS, Aston Martin V8 Vantage, and high-end models from Mercedes-Benz and BMW, offering a distinct rear-engined bias in handling feel despite its front-engine layout.

Key Features:

Distinctive transaxle layout for optimal weight distribution, powerful V8 engine, advanced (for its time) chassis and suspension, and a luxurious interior.

Manual Value Proposition:

Provides essential, in-depth technical information to maintain and repair the sophisticated Porsche 928 S4, crucial for preserving its performance and value.

📋 Manual Details

Manual Type:

Workshop Service Repair Manual

Language:

English

Format:

PDF

Page Count:

2836

Delivery Method:

Instant Download

Printable:

Yes

Compatibility:

Windows, Mac, Linux OS

Required Software:

Adobe Reader

📖 Manual Coverage

Engine:

Complete engine overhaul, including disassembly, assembly, timing, lubrication, cooling, fuel injection, ignition, and emissions control systems.

Transmission:

Automatic transmission (e.g., 4-speed automatic transaxle), including diagnosis, repair, adjustments, and fluid specifications.

Drivetrain:

Front-wheel drive system, driveshafts, differentials, and associated components.

Suspension:

Front and rear suspension systems, including components like control arms, struts, springs, shock absorbers, and alignment procedures.

Steering:

Power steering system, steering rack, linkages, and adjustments.

Brakes:

Hydraulic brake system, including ABS (Anti-lock Braking System), master cylinder, calipers, rotors, brake lines, and bleeding procedures.

Electrical:

Complete electrical system, including wiring diagrams, fuse/relay locations, battery, charging system, starting system, lighting, instrumentation, and power accessories.

Body:

Body and chassis, including exterior panels, doors, windows, sunroof, bumpers, and interior trim removal/installation.

Climate Control:

Air conditioning (A/C) and heating systems, including components, diagnosis, and refrigerant handling.

Fuel System:

Fuel tank, fuel pump, fuel lines, fuel injectors, and fuel pressure regulation.

Exhaust System:

Removal, installation, and troubleshooting of exhaust manifolds, catalytic converters, mufflers, and hangers.

Cooling System:

Radiator, water pump, thermostat, hoses, fan, and coolant flow diagnosis.

Interior Systems:

Seat removal, dashboard disassembly, door panel removal, interior trim, and headliner services.

Lighting System:

Headlights, taillights, interior lighting, and troubleshooting electrical faults related to lighting.

Fuel Tank And Lines:

Fuel tank removal and installation, fuel line routing, and leak diagnosis.

Maintenance:

Scheduled maintenance, oil changes, fluid checks, filter replacements, spark plug replacement, and general upkeep.

Troubleshooting:

Systematic diagnostic procedures for identifying and resolving common and uncommon faults.

Repair:

Detailed step-by-step instructions for repairing or replacing virtually all vehicle components.

Disassembly Assembly:

Comprehensive guidance on disassembling and reassembling all major vehicle systems and components.

Adjustments:

Precise instructions for adjusting various vehicle systems, including engine, transmission, and brakes.

Installation:

Procedures for installing new or replacement parts and components.

Torquing Procedures:

Detailed torque specifications for all critical fasteners and threaded connections, essential for proper assembly and preventing damage.

Diagnostic Procedures:

Methods for diagnosing engine performance issues, electrical faults, and mechanical problems using specified testing procedures and equipment.

Depth:

Comprehensive 'bumper-to-bumper' coverage, suitable for both professional mechanics and skilled DIY enthusiasts.

Diagrams:

Detailed illustrations, exploded diagrams, drawings, and photographs to guide repairs.

Special Tools:

Reference to specific Porsche special service tools (SSTs) and their usage.

Specifications:

Inclusion of service data, factory specifications, allowable limits, and tightening torques.

Safety Precautions:

Detailed safety notes, precautions, DANGER, CAUTION, and NOTE advisories for hazardous operations.

📊 Manual Specifications

File Format:

PDF

Print Quality:

High-resolution, suitable for printing all 2836 pages.

Searchability:

Likely text-searchable PDF for efficient information retrieval.

Binding Type:

N/A (Digital PDF)

Paper Type:

N/A (Digital PDF)

Document Completeness:

100% Complete and Intact, no missing or corrupt pages/sections.

⚙️ Engine Specifications

Engine Type:

Naturally Aspirated V8

Displacement:

5.0 Liters (4957 cc)

Bore X Stroke:

100.0 mm x 79.5 mm (approximate)

Compression Ratio:

10.0:1

Valve Train:

4 Valves per cylinder, DOHC (Dual Overhead Camshafts)

Horsepower:

310 hp @ 6000 rpm (DIN)

Torque:

317 lb-ft (430 Nm) @ 3000 rpm (DIN)

Fuel Delivery:

Bosch L-Jetronic Fuel Injection

Fuel Type:

Premium Unleaded Gasoline (91 Octane or higher)

Cooling Type:

Liquid-Cooled

Ignition Type:

Electronic Ignition

🔧 Transmission

Transmission Type:

4-Speed Automatic Transaxle (Standard)

Transmission Type Optional:

5-Speed Manual Transaxle (Limited availability, often not specified for S4 models in some markets)

Transaxle Layout:

Rear transaxle design combining transmission and differential for near 50/50 weight distribution.

📐 Dimensions

Length:

4654 mm (183.2 inches)

Width:

1785 mm (70.3 inches)

Height:

1285 mm (50.6 inches)

Wheelbase:

2700 mm (106.3 inches)

Front Track:

1490 mm (58.7 inches)

Rear Track:

1450 mm (57.1 inches)

Curb Weight:

Approximately 1650 kg (3638 lbs) for automatic transmission models.

Gross Weight Rating:

Approx. 2100 kg (4630 lbs)

Towing Capacity:

Not typically specified or recommended for this performance vehicle.

🛡️ Safety Features

Crash Test Ratings:

N/A (Modern crash test rating systems were less prevalent and standardized during the production period of these vehicles).

ABS:

Standard Anti-lock Braking System (ABS)

Traction Control:

Optional or standard on some later models.

Airbags:

Driver's side airbag standard on later models; passenger airbag became standard later.

Seat Belts:

Three-point retractable seat belts with pretensioners.

Chassis Design:

Designed with a robust chassis and crumple zones.

💡 Technology Features

Infotainment System:

Basic analog and digital displays for instrumentation. Original stereos were typically Blaupunkt or Becker units, often with cassette players. Modern upgrades are common.

Driver Assistance Features:

ABS, power steering, cruise control.

Connectivity Features:

N/A (No factory integrated connectivity features like Bluetooth or USB).

🔧 Maintenance

Oil Change Interval:

Typically every 7,500-10,000 miles or annually, whichever comes first. Consult manual for specific recommendations based on driving conditions.

Timing Belt Replacement:

Crucial maintenance item. Typically every 30,000-60,000 miles or 3-5 years, as the V8 engine is an interference design. Refer to manual for exact interval.

Major Service:

Comprehensive checks and component replacements usually recommended at 60,000 or 100,000-mile intervals.

Engine Oil:

Refer to manual for specific viscosity grade (e.g., 5W-40 or 10W-40 synthetic) and API service classification (e.g., SG or SH).

Coolant:

Porsche approved coolant mixture (typically 50/50 distilled water and ethylene glycol antifreeze).

Brake Fluid:

DOT 4 or DOT 5.1 high-performance brake fluid.

Transmission Fluid:

Specific automatic transmission fluid (ATF) as per Porsche specifications for the relevant transmission model. Refer to manual for part number.

Power Steering Fluid:

Specific hydraulic fluid as recommended by Porsche for the power steering system.

Clutch Fluid:

If equipped with manual transmission: DOT 4 brake fluid.

Differential Fluid:

Specific gear oil for the transaxle differential, refer to manual for type and capacity.

Known Issues:

Timing belt failure (critical), fuel line degradation, electrical gremlins (especially aged wiring and connectors), AC system performance, hatch strut failure, potential for rear main seal leaks, suspension bushing wear.

Manual Assistance For Issues:

This manual provides detailed troubleshooting steps and repair procedures to address these common and uncommon issues effectively.

📚 Vehicle History

Brand Heritage:

Porsche has a long-standing reputation for engineering excellence, performance, and motorsport success.

Model Evolution:

The 928 was introduced in 1977 as a more luxurious and comfortable GT alternative to the 911. The S4 variant, introduced in 1986, represented a significant update with improved aerodynamics, a larger engine, and more power.

Production Years:

1978-1995 (928 model range). S4 variant: 1986-1991.

Manufacturing Location:

Stuttgart, Germany

Sales Figures:

Total 928 production was around 61,000 units. S4 models constituted a significant portion of later production.

🏆 Awards & Recognition

Recognitions:

The Porsche 928 was lauded for its innovative engineering and luxurious GT capabilities, often featured in automotive magazines for its performance and design.

Ratings:

Consistently received high marks for driving dynamics and comfort in contemporary reviews. Valued by collectors for its unique character.