Segment:
Full-size Luxury Sedan
Brand Perception:
Performance, luxury, advanced engineering
Competitors:
Mercedes-Benz S-Class, Jaguar XJ, Cadillac Eldorado
Engineering Philosophy:
Driver-centric, high-performance inline-six engines, advanced chassis dynamics
Design Era:
Iconic BMW Neue Klasse design language influence
Engine Mechanical:
Full overhaul, diagnostics, timing, cooling, lubrication
Engine Management:
Fuel injection (L-Jetronic/Motronic), ignition system, emission control
Transmission Manual:
Clutch, gearbox overhaul, shift mechanisms
Transmission Automatic:
Hydraulic control, valve body, torque converter, fluid service
Drivetrain:
Driveshafts, differential, axle bearings
Suspension:
Front and rear suspension components, shock absorbers, springs, bushings
Steering:
Power steering system, steering rack, linkages, alignment
Brakes:
Hydraulic system, ABS (if equipped), calipers, pads, rotors, bleeding procedures
Electrical System:
Wiring diagrams, battery, charging system, starter, lighting
Body And Chassis:
Body panels, doors, windows, trim, structural components
HVAC:
Air conditioning, heating, ventilation, climate control system
Interior:
Seats, dashboard, upholstery, instrumentation
Routine Maintenance:
Oil changes, filter replacements, fluid checks, spark plugs
Diagnostics Troubleshooting:
Fault code interpretation, symptom-based diagnosis
Component Replacement:
Detailed step-by-step instructions for all major components
Rebuilding Overhauls:
Engine, transmission, differential rebuilds
Electrical Troubleshooting:
Using wiring diagrams, testing circuits, component testing
Depth:
Comprehensive (from basic maintenance to full engine rebuilds)
Detail Level:
Factory-level detail, including torque specifications and special tools
Engine Type 733I:
M30B32 (3.2L Inline-6)
Engine Type 735I:
M30B34 (3.4L Inline-6)
Horsepower 733I:
197 hp @ 5500 rpm (approx.)
Torque 733I:
214 lb-ft @ 3500 rpm (approx.)
Horsepower 735I:
218 hp @ 5200 rpm (approx.)
Torque 735I:
230 lb-ft @ 3600 rpm (approx.)
Fuel Delivery:
Bosch L-Jetronic or Motronic fuel injection
Fuel Type:
Premium Unleaded Gasoline (91+ octane recommended)
Block Material:
Cast Iron
Head Material:
Aluminum Alloy
Valvetrain:
SOHC (Single Overhead Camshaft), 2 valves per cylinder
Transmission Type Standard:
4-speed Manual (Getrag 265 - less common on US models)
Transmission Type Optional:
ZF 4HP22 4-speed Automatic
Automatic Features:
Sport/Economy modes, hydraulic control
Automatic Transmission Fluid:
Dexron III (or equivalent GM spec)
Manual Transmission Fluid:
API GL-5, SAE 75W-90 (or specific BMW recommendation)
Crash Testing Era:
Pre-modern standardized crash testing, focusing on occupant protection
ABS:
Anti-lock Braking System (standard on later models/optional on earlier)
Traction Control:
Traction control system (ASR) optional on some models
Airbags:
Driver airbag standard, passenger airbag optional/later standard
Seatbelts:
3-point seatbelts with pretensioners (front), 3-point rear seatbelts
Body Structure:
Reinforced safety cage, crumple zones
Oil Change Interval:
Every 7,500 - 10,000 miles or 12 months, whichever comes first (depending on oil type and driving conditions).
Filter Replacement Interval:
Oil filter with every oil change; Air filter every 15,000-30,000 miles; Fuel filter every 30,000-50,000 miles.
Spark Plug Replacement Interval:
Every 30,000 - 60,000 miles (depending on plug type).
Engine Oil Specification:
SAE 10W-40 or 10W-50 (check manual for specific climate recommendations), API SG or higher.
Coolant Specification:
BMW Coolant Antifreeze (blue concentrate mixed 50/50 with distilled water).
Brake Fluid Specification:
DOT 3 or DOT 4.
Common Problems Engine:
Head gasket leaks, oil pan gasket leaks, timing chain guides (on M30), fuel distributor issues (L-Jetronic).
Common Problems Electrical:
Instrument cluster failure, aging wiring harnesses, fuel pump relay issues.
Common Problems Suspension:
Worn control arm bushings, sagging rear self-leveling suspension (if equipped), strut mounts.
Common Problems HVAC:
HVAC blower motor resistors, vacuum leaks for climate control flaps.
Brand History:
Bayerische Motoren Werke AG, renowned for engineering excellence and performance vehicles since 1916.
E23 Generation:
First generation of BMW's flagship 7 Series sedan, introduced in 1977.
Evolution 733I 735I:
733i (early models, ~1977-1981) evolved into the 735i (later models, ~1980-1987) with larger displacement and improved performance.
Production Years E23:
1977-1986
Production Locations:
Dingolfing, Germany
