OM668 vs OM656

Side-by-side reliability comparison

Higher reliability score
OM656 BUY 82/100
+24 points over OM668
0 / 100
CAUTION OM668 Mercedes-Benz
0 / 100
BUY OM656 Mercedes-Benz

Specifications

OM668
OM656
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
CAUTION
BUY
Reliability
58
82
Years
1998--2004
2017--present
Displacement
1689 cc
2999 cc
Layout
I4
I6
Type
Diesel
Diesel
Power
75--95 hp
243--330 hp
Known Issues
2
2
Total Risk Cost
€800--€2,000
€500--€2,000

Character

OM668

"W168 A-Class. Same era as M166 petrol. Injector issues. Head gasket concerns. Turbo failure on higher-output version. Not Mercedes' best diesel. Better alternatives exist."

OM656

"Flagship modern MB diesel. Inline-6 smoothness returns. MHEV. GLE/GLS/S-Class. Excellent highway. Early data strong."

Issues Comparison

OM668 2

▲ HIGH
Head gasket failure €500--€1,200 80,000 km--150,000 km
● MODERATE
Injector failure €300--€800 80,000 km--150,000 km

OM656 2

● MODERATE
DPF + EGR — diesel city driving concern €400--€1,200 60,000 km--120,000 km
○ MINOR
AdBlue / SCR system consumption and faults €100--€800 30,000 km--∞

Models

OM668 2

A-Class W168 1998--2004 A-Class W168 1998--2004

OM656 3

E 400d W213 2016--2024 Sedan GLE 350d W166 2015--2019 SUV S 350d W222 2013--2020 Sedan
Full OM668 Report Full OM656 Report