OM651 (early) vs M104
Side-by-side reliability comparison
Higher reliability score
M104
BEST
85/100
+47 points over OM651 (early)
0
/ 100
AVOID
OM651 (early)
Mercedes-Benz
0
/ 100
BEST
M104
Mercedes-Benz
Specifications
OM651 (early)
M104
Brand
Mercedes-Benz
Mercedes-Benz
Verdict
AVOID
BEST
Reliability
38
85
Years
2008--2014
1990--1997
Displacement
2143 cc
3199 cc
Layout
I4
I6
Type
Diesel
Petrol Na
Power
136--204 hp
193--231 hp
Known Issues
3
1
Total Risk Cost
€2,700--€7,200
€500--€2,000
Character
OM651 (early)
"Pre-2014: injectors, timing chain, DPF. Hard to work on."
M104
"W124/R129/W140 inline-6. One of Mercedes' most reliable engines. Bulletproof bottom end. Wiring harness biodegrades (uses soy-based insulation). Head gasket solid. 400k+ km possible."
Issues Comparison
OM651 (early) 3
◆ CRITICAL
Piezoelectric injector failure (pre-2014)
◆ CRITICAL
Timing chain stretch (pre-2014)
▲ HIGH
DPF + EGR fouling (city use)
M104 1
▲ HIGH
Wiring harness biodegradation