M54B25 Engine


bmw-m54b25

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The BMW M54 (2000-2006) is an internal combustion inline-six petrol engine. Being manufactured for the BMW X5 (E53), it’s a substitute for the M52 engine.

In 2002 and 2003, it became one of the greatest engines, according to the list of 10 Best Engines by Ward’s. The BMW S54 is the identical high-performance engine, employed for the E46 M3, the Z4 M, and the Z3 M Coupe/Roadster. The BMW M56 SULEV is built on a basis of the M54, which production gradually stopped after the launch of the N52 in 2004.

The M54B25 is one of the most famous engines of the M54 series, the construction of which started in 2000 and appeared to be an excellent substitute for the M52TUB25. This series is also known for M54B22, M54B30 and S54B32 models. M54B25 and M54B30 differ in their displacement because they feature different crankshafts, which connect pistons and rods. Simultaneously, many other details are distinct, including intake manifolds, injectors, camshafts, throttles, and ECU.

The aluminum cylinder block of the latest engine is similar, featuring sleeves made of cast iron and crankshaft. In addition, it has longer connecting rods than the earlier modification, which is 145 mm long. Meanwhile, the latest variant of the engine has lighter pistons.

The other similar characteristic is the double VANOS cylinder blockhead. The newer engine has a 10 mm shorter intake manifold. The increased power of the motor is reached thanks to broad ports and channels. Besides, the engine features electronic control of throttle and electronic control unit Siemens MS43/Siemens MS45/Siemens MS45.1.

Mostly, the M54b25 was employed for the 25i cars of the BMW brand.

Unfortunately, the engine turned out to be non-competitive with the later motor variations, released in 2005-2006. Newer modifications of 2.5L N52B25 engines proved to be more efficient.

M54B25 engine specs

Manufacturer  Munich Plant
Also called BMW M54
Production 2000-2006
Cylinder block alloy Aluminum
Configuration Straight-6
Valvetrain DOHC
4 valves per cylinder
Piston stroke, mm (inch) 75 (2.95)
Cylinder bore, mm (inch) 84 (3.3)
Compression ratio 10.5
Displacement 2494 cc (152.2 cu in)
Power output 143 kW (192 HP) at 6,000 rpm
Torque output 237 Nm (175 lb·ft) at 3,500 rpm
Redline 6,500 rpm
HP per liter 77
Fuel type Gasoline
ECU Siemens MS43.0
Siemens MS45.0
Siemens MS45.1 (US)
Weight, kg (lbs) ~130 (287)
Fuel consumption, L/100 km (mpg)
-City
-Highway
-Combined
for E46 325Ci
13 (18.1)
6.9 (34.1)
9 (26.1)
Turbocharger   Naturally aspirated
Oil consumption, L/1000 km
(qt. per miles)
up to 1.0
(1 qt. per 750 miles)
Recommended engine oil 5W-30
5W-40
Engine oil capacity, L (qt.) 6.5 (6.9)
Oil change interval, km (miles)  7,000-10,000
(4,500-6,000)
Normal engine operating temperature, °C (F) ~95 (203)
Engine lifespan, km (miles)
-Official information
-Real

~300 (185)
Tuning, HP
-Max HP
-No life span loss
300+

M54-engine

M54B25 Applications

  • 2000-2002 E36/7 Z3 2.5i
  • 2000-2006 E46 325i, 325xi, 325Ci
  • 2000-2004 E46/5 325ti
  • 2000-2004 E39 525i
  • 2003-2005 E60/E61 525i, 525xi
  • 2003-2006 E83 X3 2.5i
  • 2002-2005 E85 Z4 2.5i

BMW M54B25 engine problems and reliability

  1. High consumption of motor oil. Being the main disadvantage of another engine, the M52TU, it leads to the carbonization of piston rings. It’s necessary to buy new piston rings. The elements of the M52TUB28 are suitable. Besides, it’s advisable to check the crankcase ventilation valve (PCV).
  2. Motor overheating. The problem is rather widespread among six-cylinder engines. It’s necessary to examine the radiator and make sure that it’s free of dirt. Besides, we recommend checking the presence of oxygen in the cooling system as it may cause overheating as well. If you still have trouble with overheating, pay attention to the condition of a thermostat, radiator cap, and pump.
  3. Misfire. This trouble is frequent for the M52TU as well. By buying new hydraulic lifters, you will avoid their carbonization.
  4. Oil pressure. We recommend examining oil filter housing or oil pump as the trouble can be connected with their malfunction.

Moreover, the other widespread problem is the failure of the camshaft position sensor. Besides, you may face problems with the endurance of thermostats and too high demands for motor oil. However, M54 engines are considered as more efficient than M52 ones.

If you are contemplating on buying one of M52 or M54 engines, M54B30 will be the best option thanks to its durability, power, and reliability. Also, it will be the ideal fit for the M54B30 swap.

BMW M54B25 engine tuning

Most often to increase the power of this engine it is converted into a three-liter.

For this, it is necessary to replace the crankshaft, connecting rods, injectors, ECU and the entire intake for spare parts from M54V30. In this way, you can increase the power to about 230 forces.

The use of the ESS compressor-kit will increase the engine power to about 300 “horses” on standard pistons. All would be well, but the price of this refinement discourages many owners of engines M54.

M54 Engine Parts

Last update on 2019-12-10 / Affiliate links / Images from Amazon Product Advertising API

Dan Hoffman

Dan is a co-founder of Engineswork. He knows everything about internal combustion engines. Ask your questions in comments down below this article - he will be glad to help you anytime.

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