The M54B25, a highly popular 2.5-liter engine in the M54 series (which also includes the M54B22, M54B30, and S54B32), replaced the M52TUB25 on the BMW production line in 2000.
The M54 and M52 differed in that the new engine’s cylinder block was still aluminum with cast-iron sleeves and a cast-iron crankshaft; connecting rods (145 mm) were altered; and light pistons were added. In order to increase power and allow the engine to breathe freely, the long intake manifold was replaced with a new short one (-10 mm from M52TU) with wide DISA channels. The cylinder head with double vanos remained unchanged. A Siemens MS43/MS45 control system (Siemens MS45.1 for the US) and a 64 mm electronic throttle are also utilized.
BMW vehicles with an index of 25i were equipped with this motor.
Specifications
| Production years | 2000-2006 Munich Plant |
| Displacement, cc | 2494 |
| Fuel system | injector |
| Power output, hp | 192 |
| Torque output, Nm | 245 |
| Cylinder block | aluminum R6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 84 |
| Piston stroke, mm | 75 |
| Compression ratio | 10.5 |
| Features | DISA |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | double VANOS |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 6.5 |
| Fuel type | petrol |
| Euro standards | EURO 3/4 |
| Fuel consumption, L/100 km — city — highway — combined |
14.0 7.0 9.4 |
| Engine lifespan, km | ~320 000 |
| Weight, kg | ~130 |
Disadvantages of the M54B25 engine
Even dependable BMW M54B25 engines may have issues with overheating, misfiring, and excessive oil consumption over time.
Check the condition of the thermostat and radiator cap, and determine whether the radiator needs to be cleaned if the engine overheats. aids in the cooling system’s air expulsion.
Coking of the piston rings is linked to high engine oil consumption. We must put on new rings. Additionally, examine the crankcase ventilation valve; it might need to be changed.
The hydraulic lifters need to be replaced when misfires become apparent.
You should inspect the oil pump and oil cup if the red oil light is always on. Failure of the camshaft position sensor is another frequent issue. Remember that the thread beneath the cylinder head is not very dependable.
The convenience and dependability of engine operation will be guaranteed by prompt diagnostics and replacement of worn parts.