M278 vs OM648

Side-by-side reliability comparison

Higher reliability score
OM648 BEST 90/100
+28 points over M278
0 / 100
CAUTION M278 Mercedes-Benz
0 / 100
BEST OM648 Mercedes-Benz

Specifications

M278
OM648
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
CAUTION
BEST
Reliability
62
90
Years
2010--2018
2002--2006
Displacement
4663 cc
3222 cc
Layout
V8
I6
Type
Petrol Turbo
Diesel
Power
408--455 hp
204 hp
Known Issues
2
2
Total Risk Cost
€2,500--€9,500
€450--€1,100

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."

OM648

"Modern OM606 successor. Excellent highway cruiser. Strong torque."

Issues Comparison

M278 2

◆ CRITICAL
Timing chain guide failure €2,000--€8,000 80,000 km--150,000 km
▲ HIGH
Turbo oil line leak €500--€1,500 60,000 km--120,000 km

OM648 2

● MODERATE
EGR valve fouling (city use) €300--€700 80,000 km--160,000 km
○ MINOR
Glow plugs + injector seals €150--€400 80,000 km--160,000 km

Models

M278 2

SL R231 2012--2018 S-Class W222 2013--2017

OM648 6

E-Class W210 1999--2002 C-Class W203 2001--2005 E-Class W210 1999--2002 S-Class W220 1999--2002 S-Class W220 2002--2005 E 320 CDI W211 2002--2009 Sedan
Full M278 Report Full OM648 Report