BMW M54B25

Another post as a direct result of my fascination with the E46 3 series.

The BMW M54 is a straight-6 DOHC piston engine which replaced the M52 and was produced from 2000-2006. Compared with its M42 predecessor, the M54 features electronic throttle control. The M54 uses an aluminium block and aluminium cylinder head with cast iron cylinder liners and like the technical updates of the M52, the M54 features variable valve timing for intake and exhaust valves.

The M54B25 is a 2,494 cc (152 cu in) engine with an 84 mm (3.3 in) bore and 75 mm (3.0 in) stroke. Output is 141 kW (189 hp) at 6000 rpm and 245 N-m (181 lb-ft) of torque 3500 rpm.

Displacement: 2,494 cc (152 cu in)
Power: 141 kW (189 hp) @ 6000 rpm
Torque: 245 N-m (181 lb-ft) @ 3500
Redline: 6500
Stroke: 75.0 mm (2.95 in)
Bore: 84 mm (3.3 in)
Compression: 10.5:1

Applications:

• 2001-2002 E36/7 Z3 2.5i
• 2001-2005 E46 325i/325xi
• 2001-2006 E46 325Ci
• 2001-2004 E46 325ti
• 2001-2004 E39 525i
• 2003-2005 E60/E61 525i/525xi
• 2004-2006 E83 X3 2.5i
• 2004-2006 E85 Z4 2.5i

General Information 

1 - An Ignition Coil
2 - The Oxygen Gauge
3 - Catalytic Converter
4 - V Belt
5 - A Clutch
6 - The Cooling Fluid Pump
7 - A Thermostatically Controlled Chamber
8 - Black VANOS
9 - A Hydropusher
10 - Cam Shafts

1 - A Cylinder Block Head
2 - Cam Shaft Bed
3 - A Layer Pad Of A Head Of The Cylinder Block
4 - A Camshaft Cover
5 - A Cover Of A Head of The Cylinder Block
6 - A Moulding
7 - A Layer Pad
8 - A Layer Pad
9 - An Outlet Valve
10 - An Inlet Valve
11 - Oil-Reflective Caps of Valves
12 - The Bottom Saddle of A Valve Spring
13 - Valve Springs
14 - The Top Saddle of A Valve Spring
15 - Crackers
16 - Hydropushers of Valves
17 - Cam Shafts
18 - Block VANOS
19 - Cover of GDM
20 - A Front Epiploon of A Bent Shaft
21 - Cover Gaskets of Drive Gear of GDM
22 - Chain VANOS
23 - Sprockets of Camshafts
24 - The Top Chain Tensioner
25 - The Chain Gear
26 - A Chain of Drive Gear of GDM
27 - A Camshaft Sprocket
28 - A Bent Shaft Sprocket
29 - A Chain Tensioner Boot
30 - The Chain Gear
31 - A Chain Tensioner
32 - Piston Rings
33 - A Piston Finger With Retaining Rings
34 - A Connecting Rod With The Barrel of The Top Head, A Cover and Bolts
35 - Connecting Rod Liners
36 - Radical Liners
37 - A Bent Shaft
38 - A Rear Epiploon of A Bent Shaft
39 - The Snubber of Shifting Jerks
40 - A Crankshaft Pulley
41 - A Nave
42 - A Bent Shaft Sprocket
43 - A Crankcase Oil Pan
44 - A Layer Pad
45 - The Oil Pump

Reliability

The engine is pretty economic getting decent fuel mileage (approximately 8.8 litres/100 km, Highway, and 16-26 litres/100 km Street), however the most notable issue would be BMW's cooling system which includes a ton of plastic parts which as you can guess, deteriorate overtime do to heat. This leads to catastrophic engine failure if neglected as a whole. 

The solution to this problem can be achieved by doing a cooling system refresh.