Vehicle Segment:
Executive/Luxury Sedan
Target Audience:
Affluent individuals seeking performance, comfort, and advanced engineering.
Key Competitors:
Mercedes-Benz W123, Audi 5000, Volvo 240/700 series
Design Philosophy:
Driver-focused, engineering excellence, robust build quality, balanced performance.
Manual Value Proposition:
Essential resource for maintaining and repairing a classic BMW, ensuring longevity and preserving performance.
Engine:
Complete overhaul, diagnosis, tuning, fuel injection system (Bosch L-Jetronic), cooling system, lubrication system
Transmission:
Manual and automatic transmission overhaul, clutch, driveline, propeller shaft, differentials
Suspension:
Front and rear suspension components, shock absorbers, springs, control arms, bushings, steering system, power steering
Brakes:
Hydraulic system, brake discs, pads, calipers, master cylinder, power booster, parking brake, ABS (if equipped)
Electrical:
Complete wiring diagrams, lighting system, starting and charging system, ignition system, fuses, relays, dashboard instruments, power windows, central locking
Bodywork:
Body panel repair, door mechanisms, window regulators, bumpers, trim, underbody coatings
Heating Ventilation Air Conditioning:
HVAC system diagnostics, blower motor, heater core, AC compressor and system servicing (if equipped).
Maintenance:
Routine checks, oil changes, filter replacements, spark plug service, belt adjustments, lubrication points
Troubleshooting:
Diagnostic charts, symptom analysis, common fault diagnosis for all major systems
Repair:
Step-by-step overhaul procedures for all major components, component replacement guidelines
Technical Specifications:
Torque values, clearances, alignments, electrical specifications, fluid capacities and types
Drivetrain Repair:
Detailed procedures for differential, driveshaft, and axle repairs, including U-joint replacement and axle seal servicing.
Chassis Alignment:
Wheel alignment specifications and procedures for front and rear suspensions.
Depth Of Coverage:
Comprehensive, covering from basic maintenance to complete engine and transmission rebuilds. Suitable for professional mechanics and advanced DIY enthusiasts.
Digital Format Details:
If digital (PDF), expect searchable text, high-resolution diagrams, and potentially bookmarking for easy navigation. Print quality of diagrams is crucial.
Diagram Clarity:
High-quality, clear line drawings and exploded views are essential for accurate repair work.
Binding Style:
If printed, likely a durable comb or perfect binding to withstand shop use. Spiral binding is also common for lay-flat usability.
Paper Quality:
If printed, durable, possibly glossy paper for diagrams and coated for resistance to workshop grime.
Coverage Scope:
Full factory service manual coverage, providing all necessary information for mechanical and electrical repairs.
Engine Type:
Inline-6, naturally aspirated
Displacement:
2494 cc (2.5 Liters)
Bore X Stroke:
84.0 mm x 75.0 mm
Compression Ratio:
8.8:1 (typical)
Valve Train:
SOHC (Single Overhead Camshaft), 2 valves per cylinder
Horsepower:
150 PS (148 hp; 110 kW) at 5500 rpm (approximate)
Torque:
215 Nm (159 lb-ft) at 3500 rpm (approximate)
Fuel Delivery:
Bosch L-Jetronic Electronic Fuel Injection
Fuel Type:
Unleaded Gasoline (Octane rating may vary by region, 91 RON recommended)
Crash Safety Standards:
Designed to meet 1980s safety standards; lacks modern airbags and advanced crumple zones.
Braking System:
Front ventilated discs, rear solid discs. ABS was optional on later models or specific variants, but likely not standard on 1981 525i.
Steering:
Recirculating ball with power assist
Seatbelts:
3-point front seatbelts, lap belts in rear
Body Construction:
Unibody construction with integrated safety cage elements
Audio System:
Factory AM/FM stereo with cassette player, optional premium sound systems.
Dashboard:
Analog gauges for speedometer, tachometer, fuel, engine temperature, and oil pressure. Check control panel for system status.
Cruise Control:
Optional cruise control system.
ABS:
Anti-lock Braking System was an optional feature on later E28 models, not standard on all 1981 525i variants.
Connectivity Features:
None by modern standards. Basic features like power windows, central locking (optional) were advanced for the time.
Oil Change:
Every 7,500-10,000 miles or 12 months (recommendation for modern synthetic oil may differ)
Air Filter:
Check every 15,000 miles, replace as needed
Spark Plugs:
Replace every 30,000 miles (Bosch W7DC or equivalent recommended)
Coolant Flush:
Every 2 years or 30,000 miles
Engine Oil:
SAE 20W-50 or 10W-40 (API SG or higher) - 5.7 Liters (6.0 US qt) with filter
Coolant:
BMW Blue or equivalent Ethylene Glycol based coolant (50/50 mix with distilled water)
Brake Fluid:
DOT 3 or DOT 4
Transmission Fluid Manual:
GL-5 75W-90 Synthetic Gear Oil (approx. 1.5 liters)
Transmission Fluid Automatic:
Dexron II or III (approx. 3.5-4 liters)
Common Faults Engine:
Fuel distributor diaphragm leaks, cold start valve issues, vacuum leaks, distributor O-ring leaks, oil pan gasket leaks.
Common Faults Electrical:
Failing instrument cluster, aging wiring harness, door lock actuator failures, headlight switch issues.
Common Faults Suspension:
Worn control arm bushings, trailing arm bushings, shock absorber failure, ball joint wear.
Common Faults Body:
Rust in rocker panels, wheel arches, trunk floor, and around window seals. Door seal degradation.
Bmw Legacy:
BMW's reputation for producing driver-centric, high-quality sedans with advanced engineering for their era.
E28 Introduction:
The E28 generation replaced the E12 5 Series. Introduced in 1981, it featured a more angular design, improved aerodynamics, and enhanced technology.
525I Positioning:
The 525i was a mid-range model in the E28 lineup, offering a balance of performance and luxury, slotting below the 528i and 535i.
Manufacturing Locations:
Primarily West Germany
Production Years E28:
1981-1988
