M278 vs OM654
Side-by-side reliability comparison
Higher reliability score
OM654
BEST
85/100
+23 points over M278
0
/ 100
CAUTION
M278
Mercedes-Benz
0
/ 100
BEST
OM654
Mercedes-Benz
Specifications
M278
OM654
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
CAUTION
BEST
Reliability
62
85
Years
2010--2018
2016--present
Displacement
4663 cc
1950 cc
Layout
V8
I4
Type
Petrol Turbo
Diesel
Power
408--455 hp
150--245 hp
Known Issues
2
2
Total Risk Cost
€2,500--€9,500
€500--€1,500
Character
M278
"W222 S500, W166 GLE500, W212 E550. Hot-V twin-turbo. Timing chain guides. Turbo oil line leaks. Expensive timing chain job (engine-out in some models). Powerful but costly to own."
OM654
"Best modern MB diesel. Aluminium block, low friction. Long-distance champion."
Issues Comparison
M278 2
◆ CRITICAL
Timing chain guide failure
▲ HIGH
Turbo oil line leak
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