🏷️ Basic Information

Make:

BMW

Model:

5 Series

Model Variant:

525i

Year:

1991

Chassis Code:

E34

👋 Introduction

Positioning:

The BMW 5 Series (E34) was positioned as a premium executive sedan and wagon, competing with vehicles like the Mercedes-Benz W124 E-Class and Audi V8.

Competitors:

Mercedes-Benz W124 E-Class, Audi 100/200, Volvo 240/740/940.

Design Philosophy:

The E34 generation emphasized a blend of luxury, performance, and advanced engineering, continuing BMW's 'ultimate driving machine' ethos.

Powertrain Focus:

Known for its smooth inline-six engines and refined chassis.

Utility:

Essential for owners and independent mechanics to maintain and repair the E34 525i effectively.

📋 Manual Details

Engine Coverage:

M50B25 (2.5L inline-6)

Transmission Coverage:

Manual (Getrag 260/5, 260/6) and Automatic (ZF 4HP-22EH)

Model Variant Coverage:

All 525i models, including Sedan (E34/525i) and Touring (E34/525i Touring)

Trim Level Coverage:

All trim levels for the 525i model

Estimated Page Count:

Approximately 1000-1500 pages (typical for comprehensive workshop manuals of this era)

Manual Type:

Workshop Repair and Service Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine Mechanical:

Engine assembly, disassembly, overhaul, cylinder head, block, pistons, crankshaft, camshafts, timing, lubrication system, cooling system, fuel injection (Bosch Motronic 3.1/3.3)

Engine Electrical:

Ignition system, starter, alternator, battery, engine control unit (ECU) diagnostics, sensor testing, wiring diagrams

Transmission Manual:

Clutch, gearbox assembly, shift mechanisms, driveshafts, differential

Transmission Automatic:

Torque converter, hydraulic system, valve body, electronic control, shift solenoids

Suspension:

Front and rear suspension components, shock absorbers, springs, control arms, bushings, power steering system (Servotronic)

Brakes:

Front and rear brake systems, calipers, rotors, pads, hydraulic lines, ABS (Anti-lock Braking System) components and diagnostics

Electrical System:

12V electrical system, battery, charging system, lighting, wipers, horn, interior electronics, fuse boxes, relays, wiring diagrams

Body And Chassis:

Body panel removal and installation, doors, hood, trunk, bumpers, glass, interior trim, chassis component mounting

HVAC:

Heating, Ventilation, and Air Conditioning system operation, diagnostics, component replacement (compressor, evaporator, heater core)

Fuel System:

Fuel tank, fuel pump, fuel lines, fuel filter, injectors, fuel pressure regulator

Exhaust System:

Exhaust manifold, catalytic converter, mufflers, pipes, hangers

Maintenance Procedures:

Scheduled maintenance, oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspections and replacement

Repair Procedures:

Detailed step-by-step repair instructions for all major components and systems

Troubleshooting:

Diagnostic charts, symptom-based troubleshooting guides for engine, electrical, and mechanical issues

Diagnosis:

On-board diagnostics (OBD) information for the era, error code interpretation (where applicable)

Rebuilding Procedures:

Complete engine and transmission rebuilding specifications

Electrical Diagnostics:

Wiring diagram interpretation, testing of electrical components and circuits

Depth:

Comprehensive: Covers routine maintenance, advanced diagnostics, component replacement, and full overhauls.

Diagrams:

Includes detailed exploded views, wiring diagrams, and schematics.

Specifications:

Provides torque values, clearances, fluid capacities, and tolerances for all major components.

📊 Manual Specifications

File Type:

PDF

Searchability:

Likely text-searchable for ease of use.

Digital Quality:

High resolution, suitable for printing specific sections or the entire manual.

Binding Type:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Code:

M50B25

Engine Type:

Naturally Aspirated Inline-6 (SOHC, later DOHC)

Displacement:

2494 cc (2.5 Liters)

Bore X Stroke:

84.0 mm x 75.0 mm

Compression Ratio:

8.8:1 (early SOHC) / 10.0:1 (later DOHC)

Horsepower:

170 hp @ 5800 rpm (SOHC) / 189 hp @ 6000 rpm (DOHC)

Torque:

177 lb-ft @ 4300 rpm (SOHC) / 181 lb-ft @ 4700 rpm (DOHC)

Fuel Injection:

Bosch Motronic 3.1 (SOHC) / Motronic 3.3 (DOHC)

Fuel Type:

Unleaded Gasoline (91 Octane or higher recommended)

Ignition System:

Distributorless Ignition System (DIS) with coil-on-plug (later DOHC models)

🔧 Transmission

Standard Transmission:

5-speed Manual (Getrag 260/5)

Optional Transmission:

4-speed Automatic (ZF 4HP-22EH)

Manual Gear Ratios:

Detailed in the manual, typically around 3.72:1 for 1st gear.

Automatic Features:

Electronic control, sport mode (optional).

Manual Transmission Fluid:

BMW ATF D4 or equivalent (refer to manual for exact spec and capacity, typically ~1.3 liters)

Automatic Transmission Fluid:

BMW ATF D4 or equivalent (refer to manual for exact spec and capacity, typically ~7-8 liters for a full change)

📐 Dimensions

Length:

Approx. 4720 mm (Sedan)

Width:

Approx. 1751 mm

Height:

Approx. 1412 mm (Sedan)

Curb Weight:

Approx. 1550-1600 kg

Gross Vehicle Weight Rating:

Refer to vehicle placard or manual.

Wheel Bolt Pattern:

5x120

Recommended Tire Size:

205/65R15 or 225/55R15 (standard), 225/50R16 or 235/45R17 (optional/sport wheels)

🛡️ Safety Features

Crash Test Data:

While specific NHTSA/IIHS ratings for the 1991 model may not be readily available, the E34 chassis was known for its robust structure and safety features for its era.

ABS:

Standard Anti-lock Braking System (ABS)

Traction Control:

Optional Automatic Stability Control (ASC) on some later models, not standard on all 1991 525i.

Airbags:

Driver's side airbag was optional on early E34s, becoming more common later in the generation. Passenger airbag was generally not available in 1991.

Seatbelts:

Three-point inertia-reel seatbelts for all occupants, front seatbelt pretensioners.

Body Structure:

Reinforced safety cage, crumple zones.

💡 Technology Features

Audio System:

BMW Bavaria C Business/Professional (optional RDS radio, cassette player, CD changer compatibility).

Climate Control:

Manual or optional automatic climate control (ECC - Electronic Climate Control).

Cruise Control:

Standard or optional cruise control.

Parking Assistance:

Rear parking sensors were not a factory option in 1991.

Phone Integration:

Optional integrated car phone systems were available but are now largely obsolete.

Headlights:

Halogen headlights, optional Xenon HID headlights on very late E34 models (post-facelift).

🔧 Maintenance

Oil Change Interval:

Typically every 5,000 - 7,500 miles or 6-12 months, depending on driving conditions. Refer to manual for specific recommendations.

Transmission Fluid Change:

Automatic: Every 30,000-60,000 miles. Manual: Less frequent, typically inspected rather than routinely changed.

Coolant Change:

Every 2 years or 30,000 miles (using BMW's long-life coolant).

Spark Plug Replacement:

Approximately every 30,000 - 60,000 miles depending on plug type (e.g., copper vs. platinum).

Engine Oil Specification:

API SG or higher, BMW Longlife-98 specification recommended. Viscosity: 5W-30 or 10W-40 depending on climate. Capacity: ~6.5 liters.

Coolant Specification:

BMW Blue Antifreeze/Coolant (G48) or equivalent with a 50/50 mix with distilled water. Capacity: ~9 liters.

Brake Fluid Specification:

DOT 4.

Power Steering Fluid:

ATF Dexron II/III or Pentosin CHF 11S for Servotronic models (verify with manual).

Common Failures:

Head gasket leaks, VANOS (Variable Valve Timing) issues (on later M50 DOHC engines), coolant leaks (hose, expansion tank, water pump), fuel pump failure, ABS sensor issues, window regulator failures, starter motor wear.

Preventative Maintenance:

Regular inspection and replacement of cooling hoses, proper maintenance of the VANOS system, oil pan gasket replacement (prone to leaks), differential seal checks.

📚 Vehicle History

Bmw Heritage:

BMW, founded in 1916, has a long history of producing high-quality, performance-oriented vehicles, known for their engineering excellence and driving dynamics.

E34 Introduction:

The E34 generation of the 5 Series was introduced in 1987 (Europe) and 1989 (North America), replacing the E28. It represented a significant styling and technological update.

E34 Facelift:

The E34 received a significant facelift for the 1994 model year (often referred to as 'Late Model E34' or 'LCI'), with visual updates and engine refinements. The 1991 model is considered an 'Early Model E34'.

Production Years:

E34 generation: 1987-1996

Production Location:

Primarily Dingolfing, Germany.

Sales Impact:

The E34 was a highly successful model for BMW, solidifying its position in the executive sedan market.

🏆 Awards & Recognition

Car And Driver:

The E34 5 Series was frequently featured on Car and Driver's '10Best' lists for its segment.

Automotive Journalist Acclaim:

Widely praised by automotive journalists for its driving dynamics, build quality, and refined engineering.

Iso Certification:

BMW's manufacturing processes adhered to stringent ISO quality standards during this period.