M50/M52 vs B57
Side-by-side reliability comparison
Higher reliability score
M50/M52
BEST
86/100
+4 points over B57
0
/ 100
BEST
M50/M52
BMW
0
/ 100
BUY
B57
BMW
Specifications
M50/M52
B57
Brand
BMW
BMW
Verdict
BEST
BUY
Reliability
86
82
Years
1990--2001
2015--present
Displacement
2494 cc
2993 cc
Layout
I6
I6
Type
Petrol Na
Diesel
Power
150--193 hp
265--400 hp
Known Issues
5
3
Total Risk Cost
€430--€2,200
€700--€1,400
Character
M50/M52
"Smooth, linear inline-six with bulletproof internals — 300,000 km is routine. Budget a full cooling-system refresh (plastic tank, impeller, thermostat housing) and expect VANOS seals and the oil separator to need doing. Only trap: European M52 built 1995 to early 1998 had Nikasil bores that sulphur fuel destroyed; ask for a leak-down test or proof of a replacement block. M50 and M52TU are not affected."
B57
"Smooth, torquey straight-six diesel in single-, twin- and (until 2020) quad-turbo form. Strong long-distance record. The one official problem is the EGR-cooler fire recall, which in the US/Canada hit the 2018 540d twice - check recall status by VIN. Needs long runs to keep the DPF and intake clean."
Issues Comparison
M50/M52 5
◆ CRITICAL
Nikasil cylinder-bore wear (M52 built 1995 to March 1998, non-US)
● MODERATE
Crankcase ventilation (CCV / oil separator) clogs — oil consumption, rough idle
● MODERATE
Cooling system plastics (tank, housing, impeller)
○ MINOR
VANOS oil seal wear (M50TU from 1992, M52, M52TU)
○ MINOR
Valve cover / oil pan gasket leaks
B57 3
◆ CRITICAL
EGR cooler coolant leak — intake manifold melt, fire risk (recall)
● MODERATE
Intake manifold, swirl flap and EGR valve carbon build-up
● MODERATE
DPF loading on short trips