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.
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 |
| Weight, kg | 210 |
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.
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.
Frequently asked questions about the BMW M51D25
How much power does the BMW M51D25 make?
Power output of the BMW M51D25, hp: 115 (M51D25 UL); 143 (M51D25 OL); 115 (M51D25TU UL); 143 (M51D25TU OL). Torque, Nm: 222 (M51 UL); 260 (M51 OL); 230 (M51TU UL); 280 (M51TU OL).
How much oil does the BMW M51D25 take and which one?
Engine oil capacity: 6.5 (M51 UL, M51 OL); 7.0 (M51TU UL, M51TU OL) liters. Recommended oil: 5W-40.
Does the BMW M51D25 have a timing belt or chain?
The BMW M51D25 uses a timing chain.
Is the BMW M51D25 turbocharged?
Yes, the BMW M51D25 is turbocharged (MHI TD04-11G-5 (M51 UL); MHI TD04-11G-5 (M51 OL); Garrett TB2514 (M51TU UL); MHI TD04-13T-4 (M51TU OL)).
Does the BMW M51D25 need valve clearance adjustment?
No, the BMW M51D25 has hydraulic lifters, so the valve clearances do not need to be adjusted.
How long does the BMW M51D25 last?
The typical lifespan of the BMW M51D25 is ~350 000 km with proper maintenance.
What is the fuel consumption of the BMW M51D25?
BMW 525tds 1994: city 11.3, highway 6.1, combined 8.0 L/100 km.
What cars was the BMW M51D25 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.
What are the common problems of the BMW M51D25?
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. All known problems.
