M50/M52 vs M54 — Reliability Comparison

Specifications

M50/M52

M54

Brand

BMW

Verdict

BEST

Reliability

86

Years

1990--2001

2000--2006

Displacement

2494 cc

2979 cc

Layout

I6

Type

Petrol Na

Power

150--193 hp

170--231 hp

Known Issues

5

6

Total Risk Cost

€430--€2,200

€300--€700

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."

M54

"The last of the simple BMW straight-sixes: smooth, linear and very long-lived (around 330,000 km with proper care). Nothing on it is known to destroy the engine; the bills are age-related plastics and seals - crankcase ventilation, cooling system, DISA flap, VANOS seals and oil leaks."

Issues Comparison

M50/M52 5

◆ CRITICAL

Nikasil cylinder-bore wear (M52 built 1995 to March 1998, non-US) N/A--N/A 48,000 km--N/A

● MODERATE

Crankcase ventilation (CCV / oil separator) clogs — oil consumption, rough idle €100--N/A 130,000 km--195,000 km

● MODERATE

Cooling system plastics (tank, housing, impeller) €150--€1,700 97,000 km--240,000 km

○ MINOR

VANOS oil seal wear (M50TU from 1992, M52, M52TU) €80--€200 120,000 km--200,000 km

○ MINOR

Valve cover / oil pan gasket leaks €100--€300 150,000 km--∞

M54 6

● MODERATE

Cooling system plastics — water pump, thermostat, expansion tank N/A--N/A 97,000 km--161,000 km

● MODERATE

DISA valve failure (intake manifold flap) N/A--N/A 113,000 km--161,000 km

● MODERATE

Double VANOS — solenoid and seal wear N/A--N/A N/A--N/A

● MODERATE

Crankcase ventilation (CCV) valve and hoses — oil consumption, false air €300--€700 120,000 km--N/A

○ MINOR

Oil leaks — valve cover, oil filter housing and oil pan gaskets N/A--N/A N/A--N/A

○ MINOR

Camshaft / crankshaft position sensor failure — stalling, rpm hunting N/A--N/A N/A--N/A

Models

M50/M52 12

3 Series E36 1990--1994 3 Series E36 1990--1995 5 Series E39 1996--2000 3 Series E36 1994--1999 3 Series E46 1998--2001 5 Series E39 1996--2000 3 Series E36 1995--1999 3 Series E46 1998--2000 5 Series E39 1996--2000 3 Series E36 1995--1999 Z3 E36/7 1997--2000 3 Series E46 1998--2000

M54 13

5 Series E60 2003--2007 3 Series E46 2001--2005 5 Series E39 2000--2003 5 Series E60 2003--2005 3 Series E46 2001--2005 5 Series E39 2000--2003 Z4 E85 2003--2005 X5 E53 2000--2006 5 Series E60 2003--2005 Z4 E85 2003--2005 3 Series E46 2001--2005 5 Series E39 2000--2003 Z3 E36/7 2000--2002