M156 vs OM648
Side-by-side reliability comparison
Higher reliability score
OM648
BEST
90/100
+30 points over M156
0
/ 100
CAUTION
M156
Mercedes-Benz
0
/ 100
BEST
OM648
Mercedes-Benz
Specifications
M156
OM648
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
CAUTION
BEST
Reliability
60
90
Years
2006--2015
2002--2006
Displacement
6208 cc
3222 cc
Layout
V8
I6
Type
Petrol Na
Diesel
Power
457--514 hp
204 hp
Known Issues
2
2
Total Risk Cost
€2,500--€7,500
€450--€1,100
Character
M156
"C63/E63/S63 W204/W212/W221. Head bolt failure on early units (2007-2008). Intake manifold swirl flap. Cam adjuster bolts. Incredible NA V8 sound. Later production much improved."
OM648
"Modern OM606 successor. Excellent highway cruiser. Strong torque."
Issues Comparison
M156 2
◆ CRITICAL
Head bolt failure (2007-2008)
▲ HIGH
Intake manifold swirl flap
OM648 2
● MODERATE
EGR valve fouling (city use)
○ MINOR
Glow plugs + injector seals