Engine BMW M51D25

The 2.5-liter BMW M51 diesel engine was assembled at a plant in Austria from 1991 to 2001 and installed on such popular models as the 3-Series in the E36 body and the 5-Series in the E34 and E39 bodies. This power unit was upgraded in 1996 and received a new M51TU index.

The engine was installed on:

  • BMW 3-Series E36 in 1991 – 1999;
  • BMW 5-Series E34 in 1991 – 1996; 5-Series E39 in 1996 – 2000;
  • BMW 7-Series E38 in 1996 – 2000;
  • Opel Omega B (V94) in 1994 – 2001;
  • Land Rover Range Rover 2 (P38A) in 1994 – 2002.

Specifications

Production years 1991-2001
Displacement, cc 2497
Fuel system vortex chamber
Power output, hp 115 (M51D25 UL)
143 (M51D25 OL)
115 (M51D25TU UL)
143 (M51D25TU OL)
Torque output, Nm 222 (M51 UL)
260 (M51 OL)
230 (M51TU UL)
280 (M51TU OL)
Cylinder block cast iron R6
Block head aluminum 12v
Cylinder bore, mm 80
Piston stroke, mm 82.8
Compression ratio 22.0
Features no (M51 UL)
intercooler (M51 OL)
no (M51TU UL)
intercooler (M51TU OL)
Hydraulic lifters yes
Timing drive chain
Phase regulator no
Turbocharging MHI TD04-11G-5 (M51 UL)
MHI TD04-11G-5 (M51 OL)
Garrett TB2514 (M51TU UL)
MHI TD04-13T-4 (M51TU OL)
Recommended engine oil 5W-40
Engine oil capacity, liter 6.5 (M51 UL, M51 OL)
7.0 (M51TU UL, M51TU OL)
Fuel type diesel
Euro standards EURO 1/2 (M51 UL, M51 OL)
EURO 2/3 (M51TU UL, M51TU OL)
Fuel consumption, L/100 km (for BMW 525tds 1994)
— city
— highway
— combined
11.3
6.1
8.0
Engine lifespan, km ~350 000

Disadvantages of the M51D25 engine

  • The main problem with this diesel engine is cylinder head cracking due to overheating;
  • Still here, the valve timing is often lost as a result of stretching the timing chain;
  • Poor-quality or old oil quickly affects the condition of the high-pressure fuel pump plunger pair;
  • Difficult start of a cold engine hints at the failure of the booster pump;
  • On runs over 150,000 kilometers, the turbocharger often already requires replacement.

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