Segment:
Luxury Grand Tourer (GT) Coupe
Era Competitors:
Jaguar XJ-S, Mercedes-Benz SEC-Class (W126), Porsche 944
Unique Selling Points:
BMW's characteristic inline-six engine, superior handling dynamics, driver-focused cockpit, build quality, and performance-oriented M variant.
Design Philosophy:
Elegance, performance, and driver engagement blended into a sophisticated coupe body style.
Target Audience:
Affluent individuals seeking a stylish, powerful, and engaging driving experience with German engineering heritage.
Engine Mechanical:
Full overhaul, diagnosis, timing, cooling system, lubrication, fuel delivery (mechanical injection/early EFI), exhaust
Engine Management:
Digifant/Motronic (early variants), ignition system, sensors, actuators, diagnostic trouble codes (DTCs) where applicable for the era
Transmission Manual:
Clutch, gearbox overhaul, component replacement, shift mechanism
Transmission Automatic:
ZF 4HP22, torque converter, valve body, hydraulic circuits, service procedures
Suspension:
Front MacPherson struts, rear trailing arms, shock absorbers, springs, bushings, alignment specifications
Brakes:
Front and rear disc brakes (vented front), ABS (Anti-lock Braking System) diagnosis and repair, hydraulic system, parking brake
Steering:
Power steering system, steering rack, steering column, tie rods, alignment
Electrical System:
Wiring diagrams, battery, alternator, starter, lighting, horns, power windows, mirrors, central locking, fuse box
Body And Chassis:
Body panel removal/installation, interior trim, bumpers, glass, rust prevention, jacking points
HVAC:
Heating, ventilation, air conditioning system (if equipped), refrigerant handling (R12 era)
Routine Maintenance:
Oil changes, filter replacements, spark plug replacement, fluid checks and top-offs
Troubleshooting:
Systematic diagnostic procedures, symptom-based fault finding, common problem diagnosis
Major Repairs:
Engine rebuilds, transmission overhauls, suspension component replacement, brake caliper rebuilding
Component Removal Installation:
Detailed instructions for removing and refitting all major mechanical and electrical components
Special Tools:
Identification and usage of specialized BMW tools required for specific repair procedures
Depth:
Comprehensive; covers everything from basic maintenance to full engine and transmission rebuilds. Suitable for professional mechanics and skilled DIY enthusiasts.
Type:
Naturally Aspirated Inline 6-Cylinder, SOHC
Displacement:
3.4 Liters (3430 cc)
Bore X Stroke:
92 mm x 86 mm
Compression Ratio:
8.0:1 (approx.)
Horsepower:
218 PS (215 hp) @ 5,200 RPM (Euro Spec)
Torque:
304 Nm (224 lb-ft) @ 3,000 RPM (Euro Spec)
Type:
Naturally Aspirated Inline 6-Cylinder, DOHC (M Power)
Displacement:
3.5 Liters (3453 cc)
Bore X Stroke:
93.4 mm x 84 mm
Compression Ratio:
10.5:1
Horsepower:
286 PS (282 hp) @ 6,500 RPM (Euro Spec)
Torque:
333 Nm (246 lb-ft) @ 5,000 RPM (Euro Spec)
0 60 Mph 635Csi Auto:
7.6 seconds (approx.)
0 60 Mph M635Csi Manual:
6.5 seconds (approx.)
635Csi:
Bosch L-Jetronic Fuel Injection (early models) / Motronic EFI (later models)
M635Csi:
Bosch Motronic EFI
Recommended:
Premium Unleaded Gasoline (91+ Octane)
Type:
4-Speed Manual Getrag 265
Type:
3-Speed Automatic ZF 4HP22
Type:
5-Speed Manual Getrag 280 (dogleg first gear)
Limited Slip Differential:
Optional on 635CSi, standard on M635CSi
Manual Gearbox Fluid:
GL-4 Gear Oil (e.g., Castrol EPX 80W-90, 75W-90)
Automatic Gearbox Fluid:
ATF Dexron III or equivalent
Era Safety Standards:
Reflects early 1980s safety design; equipped with safety features standard for the period.
ABS:
Available and optional on later models, standard on some M variants. Requires specific diagnostic procedures.
Limited Slip Differential:
Enhances traction and stability under acceleration.
Seatbelts:
Three-point inertia reel seatbelts
Structure:
Reinforced safety cage, crumple zones, side impact protection beams.
Headrests:
Adjustable front and rear headrests
Oil Change:
Every 10,000-15,000 km (6,000-10,000 miles) or annually, whichever comes first.
Spark Plugs:
Every 40,000-60,000 km (25,000-37,500 miles) depending on plug type (copper vs. platinum).
Coolant Flush:
Every 2-3 years.
Timing Belt Tensioner System:
M30 engines use a timing chain; S38 engines use a timing chain. Periodic inspection of tensioner and guides recommended, typically around 100,000 miles / 160,000 km.
Engine Oil Capacity M30:
7.5 Liters (7.9 US Quarts) with filter
Engine Oil Recommendation:
15W-40 or 20W-50 depending on climate. Synthetic blends or full synthetics can be used if compatible.
Coolant Type:
Ethylene Glycol based antifreeze, typically a 50/50 mix with distilled water. BMW Blue or equivalent.
Rust:
Common in wheel arches, sills, rocker panels, sunroof tray, and rear shock mounts.
Fuel Lines:
Degradation of rubber fuel lines can lead to leaks.
Rubber Bushings:
Wear and tear on suspension and drivetrain bushings (control arm, subframe, trailing arm).
Electrical Connectors:
Corrosion or poor connections in engine bay and chassis wiring harnesses.
Oil Pan Gasket:
Leaking oil pan gaskets are common.
Cooling System:
Radiator leaks, failing water pumps, and thermostat issues.
M635Csi S38 Engine:
Timing chain guides, valve stem seals, and carbon buildup can occur if not maintained properly.
Bmw Legacy:
BMW, Bayerische Motoren Werke AG, renowned for its 'Ultimate Driving Machine' philosophy, focusing on performance, engineering, and driver involvement.
E24 Introduction:
Introduced in 1976 as the successor to the E9 coupe, designed by Paul Bracq. The 635CSi variant arrived in 1978 with the larger 3.5-liter engine.
Facelift Lci:
Major facelift in 1982 (for model year 1983), introducing revised aerodynamics, improved interior, and updated engine options, including the 3.4L M30B34.
M635Csi Introduction:
Launched in 1983, featuring the potent 286 hp S38B35 engine from the M1 supercar, upgraded suspension, brakes, and distinct M styling cues.
Production Period:
1976-1989
Production Location:
Dingolfing, Germany
Total M635Csi Units:
approx. 4,500 (across all markets and variants)
