M256 vs OM654
Side-by-side reliability comparison
Higher reliability score
OM654
BEST
85/100
+5 points over M256
0
/ 100
BUY
M256
Mercedes-Benz
0
/ 100
BEST
OM654
Mercedes-Benz
Specifications
M256
OM654
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
BUY
BEST
Reliability
80
85
Years
2017--present
2016--present
Displacement
2999 cc
1950 cc
Layout
I6
I4
Type
Petrol Turbo
Diesel
Power
367--435 hp
150--245 hp
Known Issues
2
2
Total Risk Cost
€1,200--€4,000
€500--€1,500
Character
M256
"MB returns to I6. EQ Boost. Smooth, powerful. Still proving itself."
OM654
"Best modern MB diesel. Aluminium block, low friction. Long-distance champion."
Issues Comparison
M256 2
● MODERATE
48V ISG starter-generator complexity
○ MINOR
Timing chain (early data building)
OM654 2
○ MINOR
DPF — better than older MB diesels but still diesel
○ MINOR
Minor EGR fouling (best-in-class but not immune)
Models
OM654 47
B-Class
A-Class
GLA
A-Class
C-Class
C-Class
GLC
E-Class
GLC
E-Class
GLE
E-Class
C-Class
C-Class
GLC
GLC
E-Class
C-Class
E-Class
GLC
C-Class
C-Class
GLC
E-Class
CLA
A-Class
CLA
B-Class
GLA
GLA
A-Class
E-Class
S-Class
GLE
E-Class
G-Class
E-Class
G-Class
G-Class
S-Class
S-Class
S-Class
GLE
S-Class
C 220d Wagon
E 220d Wagon
GLC 220d Coupe