🏷️ Basic Information

Make:

BMW

Model:

525i

Year:

1981

Chassis Code:

E28

👋 Introduction

Era Positioning:

Mid-size luxury/sport sedan, positioned as a capable driver's car with German engineering and refinement.

Key Competitors:

Mercedes-Benz W123 series, Audi 100, Volvo 240 series, Jaguar XJ-S (in some markets).

Engineering Focus:

Driver-centric experience, balanced chassis, quality construction, robust engine performance.

Design Philosophy:

Understated elegance, aerodynamic efficiency, functional interior.

📋 Manual Details

Primary Coverage:

Full Service and Repair

Secondary Coverage:

Maintenance, Troubleshooting, Rebuilding, Refurbishing, Restoration

Estimated Pages:

Large; typically 800+ pages for comprehensive manuals of this era

Type:

Service Repair Manual

Language:

English

Format:

Digital (likely PDF)

📖 Manual Coverage

Engine Mechanical:

Engine assembly, cylinder head, pistons, crankshaft, camshaft, timing, lubrication, cooling system

Engine Management:

Fuel injection (Bosch L-Jetronic), ignition system, emission controls, diagnostics

Transmission Manual:

Clutch, gearbox overhaul, shift linkage, driveshafts

Transmission Automatic:

Automatic transmission overhaul (if applicable to specific 525i variant), hydraulic systems, cooling

Suspension:

Front suspension (MacPherson struts), rear suspension (semi-trailing arms), springs, shock absorbers, bushings

Steering:

Power steering system, steering rack, steering column, alignment specifications

Brakes:

Front disc brakes, rear disc brakes, hydraulic system, parking brake, ABS (if equipped)

Electrical System:

Wiring diagrams, battery, alternator, starter, lighting, gauges, control modules

Body And Interior:

Body panels, doors, windows, seats, trim, HVAC system, sound deadening

Maintenance:

Oil changes, filter replacements, spark plug service, fluid checks and changes, belt inspection/replacement

Troubleshooting:

Diagnostic procedures for engine, electrical, and mechanical issues, fault code interpretation (if applicable)

Repair:

Step-by-step instructions for component removal, overhaul, and installation

Rebuild:

Detailed engine and transmission rebuild procedures, including specifications and tolerances

Refurbishment Restoration:

Guidance on restoring specific components and systems to original specifications

Depth:

Comprehensive; covers basic maintenance to complete engine and transmission rebuilds, including electrical diagnostics

📊 Manual Specifications

Digital Quality:

High resolution, searchable text (ideal for PDF)

Print Readability:

Clear, legible text and diagrams suitable for printing

Physical Binding:

Spiral or Perfect Bound (typical for printed manuals)

Paper Quality:

Durable, high-quality paper stock to withstand workshop use

⚙️ Engine Specifications

Engine Code:

M30B28 (Often derived from the larger M30 family, though specific 525i designations can vary slightly by region or year updates within the E28 generation. The '2.5' designation likely refers to a variant of the M30 inline-six, potentially with a different bore/stroke combination or market-specific tuning. For 1981, it would most commonly be a 2.5L variant of the M30).

Engine Type:

Inline 6-cylinder, SOHC

Displacement:

Approximately 2.5 Liters (2494 cc)

Horsepower:

Approximately 150-155 hp @ 5500 rpm (varies by market and specific tuning)

Torque:

Approximately 165-170 lb-ft @ 3500 rpm (varies by market and specific tuning)

Fuel Delivery:

Bosch L-Jetronic Electronic Fuel Injection (EFI)

Ignition System:

Electronic Ignition (Baehr or Bosch)

Ratio:

Typically around 8.5:1 to 9.0:1

Type:

Liquid-cooled, pressurized

🔧 Transmission

Type:

4-speed Manual Transmission (Getrag 260 series)

Type:

3-speed Automatic Transmission (ZF 3HP22)

Manual Gear Ratios:

Detailed ratios provided in the manual (e.g., 1st: 3.83, 2nd: 2.27, 3rd: 1.39, 4th: 1.00)

Automatic Features:

Lock-up torque converter, sport/economy modes (depending on specific variant).

Manual:

BMW ATF Dexron II or equivalent (refer to manual for exact spec)

Automatic:

BMW ATF Dexron II or equivalent (refer to manual for exact spec)

📐 Dimensions

Length:

Approximately 4620 mm (181.9 in)

Width:

Approximately 1700 mm (66.9 in)

Height:

Approximately 1400 mm (55.1 in)

Wheelbase:

Approximately 2770 mm (109.1 in)

Curb Weight:

Approximately 1350-1450 kg (2976-3197 lbs)

Gross Weight:

Consult manual for specific GVWR

Wheel Bolt Pattern:

5x120mm

Standard Tire Size:

195/70HR14 or 205/55VR15 (depending on trim and options)

🛡️ Safety Features

Era Safety Standards:

Designed to meet 1980s safety regulations; includes crumple zones, safety steering column. ABS was an option on later E28 models, potentially available on late '81 or '82 models depending on market introduction.

ABS:

Optional on some models

Seatbelts:

3-point front, 2-point rear (later models often had 3-point rear)

Construction:

Integrated safety cage, reinforced chassis, energy-absorbing interior materials.

💡 Technology Features

Audio System:

Factory AM/FM radio with cassette player, optional premium sound systems.

Controls:

Analog knobs and buttons for climate control and audio.

Cruise Control:

Optional

HVAC System:

Manual or optional automatic climate control system with air conditioning.

Dashboard:

Comprehensive analog gauges including speedometer, tachometer, fuel level, oil pressure, coolant temperature, and economy gauge. Warning lights for system status.

🔧 Maintenance

Oil Change:

Every 7,500-10,000 miles or 12 months (refer to manual for exact interval based on driving conditions).

Spark Plugs:

Inspect/replace at 20,000-30,000 miles.

Coolant Flush:

Every 2-3 years or 30,000 miles.

Transmission Fluid Change:

Manual: Inspect at 50,000 miles, change as needed. Automatic: Every 40,000-50,000 miles.

Engine Oil:

API SF or SG, SAE 20W-50 or 10W-40 (refer to manual for specific viscosity based on temperature range).

Coolant:

BMW Blue Antifreeze/Coolant concentrate (50/50 mix with distilled water).

Brake Fluid:

DOT 3 or DOT 4 (refer to manual for specific type).

Common Problems:

Rust (especially in wheel arches, rocker panels), vacuum leaks, fuel distributor issues (L-Jetronic), headliner sagging, aging rubber components (hoses, bushings), electrical connection corrosion, rear subframe mounting points.

Engine Wear:

Potential for oil consumption in high-mileage engines, timing belt tensioner wear (if applicable to M30 variant, though primarily chain-driven).

📚 Vehicle History

Bmw Legacy:

BMW's reputation for sporty sedans, superior engineering, and driver engagement.

E28 Generation:

The E28 was the second generation of the BMW 5 Series, succeeding the E12. It was introduced in 1981 and ran until 1987. It represented a significant step forward in terms of technology, refinement, and safety compared to its predecessor.

Manufacturing Location:

Germany (Dingolfing Plant)

Production Years:

1981-1987 (E28 generation)

🏆 Awards & Recognition

Bmw 5 Series Legacy:

While specific awards for the '1981 525i' might be hard to pinpoint as an individual model, the E28 generation as a whole was highly regarded for its driving dynamics and engineering, contributing to BMW's ongoing reputation for 'The Ultimate Driving Machine'.