M51 vs N52

Side-by-side reliability comparison

Higher reliability score
N52 BEST 90/100
+22 points over M51
0 / 100
ACCEPTABLE M51 BMW
0 / 100
BEST N52 BMW

Specifications

M51
N52
Brand
BMW
BMW
Verdict
ACCEPTABLE
BEST
Reliability
68
90
Years
1991--2000
2004--2015
Displacement
2497 cc
2996 cc
Layout
I6
I6
Type
Diesel
Petrol Na
Power
115--143 hp
190--272 hp
Known Issues
2
3
Total Risk Cost
€1,500--€3,700
€250--€900

Character

M51

"Pre-common-rail indirect injection diesel. Cast iron tractor engine. Injection pump main failure at 250k+ km. No swirl flaps. No DPF."

N52

"Last great NA six. Lighter (magnesium block), smoother, higher-revving than M54. 250k+ km."

Issues Comparison

M51 2

▲ HIGH
Injection pump hot start failure €500--€1,200 200,000 km--350,000 km
▲ HIGH
Cylinder head cracking €1,000--€2,500 200,000 km--350,000 km

N52 3

● MODERATE
Coolant expansion tank / hose failure €100--€300 80,000 km--150,000 km
● MODERATE
VANOS solenoid / oil feed failure €150--€400 80,000 km--160,000 km
○ MINOR
Hydraulic lifter tick on cold start €0--€200 60,000 km--∞

Models

M51 3

3 Series E36 1991--1996 5 Series E39 1996--2000 3 Series E36 1993--1999

N52 9

6 Series E63 2004--2010 5 Series E60 2005--2007 5 Series E60 2005--2007 3 Series E90 2005--2007 Z4 E85 2006--2008 5 Series E60 2005--2007 X5 E70 2007--2010 3 Series E90 2005--2007 1 Series E87 2005--2011
Full M51 Report Full N52 Report