Engine BMW M50B25 / M50B25TU

In 1990, the inline 6-cylinder M20B25 engine from BMW was replaced by a new, much more powerful and advanced M50B25. The unit belongs to the new M50 family, the same line includes M50B20, M50B24, S50B30, S50B32. The main difference between M50 and M20 engines is the cylinder head. In the new engine, the cylinder head is already two-shaft, has hydraulic lifters, the number of valves is 24. The gas distribution mechanism in the M50 engines is now driven by a chain. According to the manufacturer, it serves about 250 thousand km, most often longer.


Production years 1990-1996 Munich Plant
Displacement, cc 2494
Fuel system injector
Power output, hp 192
Torque output, Nm 245
Cylinder block cast iron R6
Block head aluminum 24v
Cylinder bore, mm 84
Piston stroke, mm 75
Compression ratio 10.0
10.5 (TU)
Features no
Hydraulic lifters yes
Timing drive chain
Phase regulator no
single VANOS (TU)
Turbocharging no
Recommended engine oil 5W-30
Engine oil capacity, liter 5.75
Fuel type petrol
Euro standards EURO 1
Fuel consumption, L/100 km (for E36 325i)
— city
— highway
— combined
Engine lifespan, km ~400 000
Weight, kg ~198

Disadvantages of the M50B25 engine

  1. Overheating. The M50 unit is characterized by an increase in operating temperature. If overheating is detected, it is necessary to diagnose the radiator as soon as possible (for the formation of air locks) and its cover, thermostat and pump.
  2. Misfire. Inspect the ignition module, injector and spark plugs.
  3. The RPM are jumping. The problem is a broken or dirty idle valve. The reason may be hidden in the throttle sensor, temperature sensor and lambda probe.
  4. M50 Vanos. Signs – rattling, reduced power, jumping rpm. The solution to the problem is to buy a vanos repair kit.

Also, M50 engines consume almost 1 liter of oil for every thousand km. Sump gaskets and valve cover gaskets, oil dipstick may start to leak. The expansion tank will often crack. Problems are also created by the camshaft and crankshaft sensors, coolant temperature. Most of the disadvantages of the engine are due to age and the nature of operation. However, with proper operation and reasonable maintenance, its resource can be far beyond 400 thousand km.

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