BMW Buyer's Guide

Comprehensive Used Car Analysis
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M73B54 5.4L V12 Petrol
M73B54 5.4L V12 Petrol
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M73B54

5.4L V12 Petrol
M-series • M73 family • 1994–2001
42%
Engine Reliability
BMW's naturally aspirated V12 – essentially two M40 6-cylinder engines joined together. Offers silky smooth, effortless power but extraordinary complexity. The dual ECU system means double the diagnostic headaches. 24 spark plugs and 12 ignition coils make routine maintenance expensive. A grand tourer engine that demands a grand maintenance budget.
5.4L
Displacement
V12
Layout
326 hp
Power
490 Nm
Torque
Petrol
Fuel
Naturally aspirated
Aspiration
Technology & Features
Dual ECU system (one per bank)Individual throttle bodiesNikasil liners (early) / Alusil (late)
Fuel SystemPort injection
ValvetrainSOHC 24-valve
Used In 1 Application
7 Series E38 750i, 750iL
2
Known Issues
0
Critical
1
Wear Items
1
Applications

Known Issues – M73B54

high Dual ECU Synchronization Issues Common (~30%)
The V12 uses two ECUs (one per bank). Synchronization issues and ECU failures cause running problems – the engine may run on only 6 cylinders.
Typical Mileage
100,000–200,000 km
Est. Repair Cost
€500–€2,000
DIY Friendly
✗ Specialist
Running on 6 cylindersMisfiresCheck engine light
medium Ignition System Failures Common (>35%)
24 spark plugs and 12 coils – failures are inevitable and expensive to diagnose across 12 cylinders.
Typical Mileage
60,000–100,000 km
Est. Repair Cost
€400–€1,000
DIY Friendly
✓ Yes
MisfiresRough runningPoor fuel economy

Wear & Maintenance – M73B54

Spark Plugs (24 total) Every 40,000 km
NewReplace
Replacement Cost€200–€400
Wear Factor65%

Applications (1)

7 Series E38

E38
1994–2001
Variants750i, 750iL
Power326 hp
Torque490 Nm
BodySedan
Reliability55%
Car-Specific Issues (E38)
highSelf-Levelling Suspension Failure
lowWindow Regulator Failure
mediumA/C System (Leaks & Compressor)

Transmissions (1)

5-Speed Automatic (GM/ZF)
5-Speed Automatic (GM/ZF)
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5-Speed Automatic (GM/ZF)

GM / ZF • 5-speed automatic • 1994–2007

Early generation 5-speed automatics. The GM units are generally reliable but can develop issues if the fluid is never changed. BMW's 'lifetime fill' claim is widely disputed – regular fluid changes significantly extend life.
Known Issues1
medium Harsh Shifting / Slipping Common (>30%)
Without regular fluid changes, the transmission develops harsh upshifts and may slip under load.
Typical Mileage
120,000–200,000 km
Est. Repair Cost
€200–€500 (fluid+filter) or €2,000+ (rebuild)
DIY Friendly
✗ Specialist
Hard shiftsSlipping between gearsDelayed engagement
Wear Items
Transmission Fluid & Filter Every 80,000 km
NewReplace
Replacement Cost€200–€400
Wear Factor50%
Fluid TypeDexron III / Esso LT 71141
Service IntervalEvery 80,000 km (BMW claims lifetime)