🏷️ Basic Information

Make:

BMW

Model:

5-Series

Chassis Code:

E34

Model Variant:

525i

Model Years Covered:

1988, 1989, 1990, 1991

Engine Code Relevant:

M50B25

👋 Introduction

Positioning E34:

The E34 generation represented BMW's fifth generation of the 5-Series executive sedan, known for its blend of luxury, performance, and engineering refinement. The 525i was a popular mid-range model, offering a balance of power and efficiency powered by BMW's acclaimed inline-six engines.

Competitors Era:

Competed against luxury sedans such as the Mercedes-Benz W124 E-Class, Audi V8 Quattro, Lexus LS 400, and Jaguar XJ.

Design Philosophy:

Iconic BMW ' Hofmeister kink' design, aerodynamic styling, driver-focused cockpit.

Driving Dynamics:

Renowned for balanced handling, rear-wheel drive chassis, and a refined ride quality.

Manual Value Proposition:

Provides the authoritative information required for accurate diagnosis, repair, and maintenance, ensuring the longevity and optimal performance of the E34 525i.

📋 Manual Details

Manual Type:

Official Factory Service Repair Manual

Language:

English

Format:

Digital (printable)

Content Depth:

Comprehensive

Target Audience:

Professional Technicians and Experienced DIY Enthusiasts

📖 Manual Coverage

Engine:

Complete service, repair, and overhaul for the M50B25 inline-6 engine

Fuel System:

Fuel injection (Bosch Motronic), fuel pump, injectors, lines, tank, pressure regulation

Ignition System:

Electronic ignition control, coil packs, spark plugs, sensors

Cooling System:

Radiator, water pump, thermostat, hoses, fan clutch, coolant specifications

Exhaust System:

Exhaust manifold, catalytic converter, mufflers, pipework, emissions control

Transmission Manual:

Service and repair for Getrag 260 5-speed manual gearbox, clutch assembly, driveline

Transmission Automatic:

Service and repair for ZF 4HP22 EH 4-speed automatic transmission, torque converter, valve body, control systems

Suspension:

Front McPherson struts, rear multi-link suspension, springs, dampers, bushings, alignment specifications

Steering:

Power steering system, steering rack, pump, fluid specifications, steering column

Brakes:

Front ventilated discs, rear solid discs, ABS (Anti-lock Braking System) operation, hydraulic system, bleeding procedures

Electrical System:

Wiring diagrams, fuse box locations, starter, alternator, battery, lighting systems

Climate Control:

HVAC system, A/C compressor, refrigerant, heater core, blower motor, controls

Body And Chassis:

Body panel removal/installation, door mechanisms, glass, seals, chassis structure, corrosion protection

Interior:

Seat removal/installation, dashboard components, trim panels, sound insulation

Maintenance:

Oil changes, filter replacements, spark plug replacement, fluid checks and top-offs, belt inspections

Troubleshooting:

Diagnostic flowcharts for common symptoms (e.g., starting issues, poor performance, warning lights)

Repair:

Detailed step-by-step repair procedures for all major systems, including component removal, overhaul, and reassembly

Diagnostics:

Fault code retrieval (where applicable for the era), sensor testing, component testing procedures

Rebuilds:

Engine, transmission, differential, and major component rebuild procedures with specifications

Specifications:

Torque values, clearances, tolerances, fluid capacities, and diagnostic parameters

Depth:

Full factory level detail, covering everything from routine maintenance to complete engine rebuilds and complex diagnostics

📊 Manual Specifications

Digital Format:

PDF

Searchability:

Text-searchable for quick information retrieval

Print Readability:

High-resolution for clear text and diagrams

Print Scalability:

Printable on demand, allowing users to print specific sections or the entire manual

Physical Binding:

N/A (Digital Product)

Physical Paper Type:

N/A (Digital Product)

Manual Completeness:

Complete official factory service manual

⚙️ Engine Specifications

Engine Type:

Inline 6-cylinder, naturally aspirated

Engine Code:

M50B25

Displacement:

2494 cc (2.5 Liters)

Bore X Stroke:

84.0 mm x 75.0 mm

Compression Ratio:

8.8:1 (Euro spec), 10.0:1 (US spec)

Horsepower Hp:

170 hp @ 5500 rpm (Euro spec), 189 hp @ 6000 rpm (US spec for M50)

Torque Lb Ft:

170 lb-ft @ 4300 rpm (Euro spec), 181 lb-ft @ 4700 rpm (US spec for M50)

Fuel Delivery:

Bosch Motronic Electronic Fuel Injection (EFI)

Fuel Type:

Unleaded Gasoline (Premium Unleaded Recommended)

Fuel Pump Type:

In-tank electric

ECU Type:

Bosch Motronic M2.7 / M3.3

Coolant Capacity:

Approximately 8.5 liters (17.9 pints)

Oil Capacity:

Approximately 6.5 liters (6.9 US Quarts) with filter change

🔧 Transmission

Type:

Getrag 260 5-speed Manual Transmission

Type:

ZF 4HP22 EH 4-speed Automatic Transmission

Manual Gear Ratios:

Typical ratios: 1st: 4.23:1, 2nd: 2.52:1, 3rd: 1.66:1, 4th: 1.22:1, 5th: 1.00:1, Reverse: 3.71:1

Automatic Transmission Control:

Electronic Hydraulic control with Comfort/Sport modes on later E34 models

Transmission Fluid Type:

BMW MTF LT-2 or equivalent API GL-4 SAE 75W-90 gear oil

Transmission Fluid Type:

BMW LT 71141 or equivalent Dexron III/Mercon ATF

📐 Dimensions

Length:

Approx. 4720 mm (185.8 inches)

Width:

Approx. 1751 mm (68.9 inches)

Height:

Approx. 1410 mm (55.5 inches)

Wheelbase:

Approx. 2763 mm (108.8 inches)

Curb Weight Manual:

Approx. 1500-1550 kg (3307-3417 lbs)

Curb Weight Automatic:

Approx. 1550-1600 kg (3417-3527 lbs)

Gross Vehicle Weight Rating:

Varies by configuration, typically around 2000-2050 kg

Trunk Volume:

Approx. 500 liters (17.7 cubic feet)

🛡️ Safety Features

Crash Test Era:

Safety standards and testing methodologies were different during this period; comprehensive modern crash ratings are not directly applicable but the E34 featured a robust safety cell.

ABS:

Standard Bosch Anti-lock Braking System (ABS) on most models

Traction Control:

Optional ASC (Automatic Stability Control) or ASC+T (Traction Control) on some later models

Airbags:

Driver's airbag standard from late 1991/early 1992, optional on earlier models. Passenger airbag optional.

Seatbelts:

Three-point inertia-reel seatbelts with front-seat pretensioners

Chassis Design:

Reinforced safety cell, crumple zones front and rear

💡 Technology Features

Audio System:

Optional upgraded Hi-Fi systems, cassette player, optional CD changer.

Onboard Computer:

Optional On-Board Computer (OBC) providing trip data, fuel economy, and system checks.

Cruise Control:

Standard or optional cruise control system.

Phone Integration:

Optional early mobile phone integration kits were available.

🔧 Maintenance

Oil Change Interval:

Every 10,000-15,000 km (6,000-9,000 miles) or annually, depending on driving conditions. The manual provides specific guidance based on BMW's condition-based service system.

Air Filter Replacement:

Every 30,000-40,000 km (18,000-25,000 miles)

Spark Plug Replacement:

Every 40,000-60,000 km (25,000-37,000 miles) for standard plugs, longer for platinum/iridium

Transmission Fluid Change Manual:

Recommended every 80,000-100,000 km (50,000-60,000 miles)

Transmission Fluid Change Automatic:

Recommended every 60,000-80,000 km (37,000-50,000 miles) for optimal performance

Engine Oil Specification:

API SG, ACEA A2 or A3, SAE 5W-30, 5W-40, 10W-40, or 10W-50 depending on ambient temperature. The manual specifies BMW High Performance SAE 5W-40.

Coolant Specification:

BMW Blue Antifreeze/Coolant or equivalent ethylene glycol-based coolant with corrosion inhibitors (typically a 50/50 mix with distilled water)

Brake Fluid Specification:

DOT 4

Power Steering Fluid Specification:

BMW Power Steering Fluid or Pentosin CHF 11 S

Engine M50:

Vanous shaft seal leaks (e.g., rear main seal, oil pan gasket), radiator support cracking, thermostat housing leaks, VANOS solenoid issues (on M50TU or later M50 engines)

Cooling System:

Plastic coolant expansion tanks can become brittle and crack, water pump impeller can disintegrate, fan clutch failure.

Suspension Bushings:

Front control arm bushings, rear trailing arm bushings, and subframe bushings are common wear items.

Electrical:

ABS sensor failures, O2 sensor degradation, Maf sensor issues, door lock actuator failures, EWS immobilizer issues (later models).

Interior:

Headliner sagging, seat bolster wear, dashboard pixelation on OBC (On-Board Computer).

📚 Vehicle History

Bmw Legacy:

BMW has a long-standing reputation for building driver-oriented luxury and performance vehicles. The 5-Series is a cornerstone of the brand, symbolizing executive transport with sporting credentials.

E34 Introduction:

The E34 generation was introduced in late 1987 for the 1988 model year, succeeding the E28. It featured a more modern, aerodynamic design and advanced engineering.

E34 Updates:

Facelifted in 1994 (outside the scope of this manual but part of the E34 lifecycle), with mild styling revisions and updated engines. The 525i, particularly with the M50 engine, represented a significant performance upgrade over its predecessor.

Production Years E34:

1987–1996

Manufacturing Locations:

Primarily Dingolfing, Germany

🏆 Awards & Recognition

E34 Reputation:

The E34 5-Series was consistently praised by automotive journalists for its superior handling, build quality, and refined driving experience, often earning 'Best Luxury Sedan' or similar accolades in its class during its production run.