BMW M51
title: "BMW M51" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["bmw-engines", "opel-engines", "land-rover-engines", "1991-introductions", "diesel-engines-by-model", "straight-six-engines"] topic_path: "general/bmw-engines" source: "https://en.wikipedia.org/wiki/BMW_M51" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::data[format=table title="Infobox automobile engine"]
| Field | Value |
|---|---|
| name | BMW M51 |
| image | M51_Motor.JPG |
| manufacturer | BMW |
| production | 1991-2000 |
| predecessor | BMW M21 |
| successor | BMW M57 |
| configuration | Inline-6 |
| displacement | 2497 cc |
| bore | 80 mm |
| stroke | 82.8 mm |
| block | Cast iron |
| valvetrain | SOHC 2 valves x cyl. |
| compression | 22.0:1 |
| turbocharger | Single turbo, tds-engines also have an intercooler |
| fuelsystem | Swirl-chamber-injection |
| management | Bosch DDE 2.1 |
| fueltype | Diesel fuel (DIN 51601) |
| coolingsystem | Water-cooled |
| power | 85-105 kW |
| torque | 222-280 Nm |
| weight | 132 kg |
| :: |
| name = BMW M51 | image = M51_Motor.JPG | manufacturer = BMW | aka = | production = 1991-2000 | predecessor = BMW M21 | successor = BMW M57 | configuration = Inline-6 | displacement = 2497 cc | bore = 80 mm | stroke = 82.8 mm | block = Cast iron | head = | valvetrain = SOHC 2 valves x cyl. | compression = 22.0:1 | supercharger = | turbocharger = Single turbo, tds-engines also have an intercooler | fuelsystem = Swirl-chamber-injection | management = Bosch DDE 2.1 | fueltype = Diesel fuel (DIN 51601) | oilsystem = | coolingsystem = Water-cooled | power = 85-105 kW | specpower = | torque = 222-280 Nm | length = | width = | height = | diameter = | weight = 132 kg
The BMW M51 is an inline-6 cylinder Diesel engine produced by the Upper Austrian BMW plant in Steyr from July 1991 through February 2000. Its predecessor is the BMW M21; the successor is the BMW M57.
Description
The M51 is a water-cooled and turbocharged inline six-cylinder diesel engine. It is an indirect injection design with fuel supplied by a Bosch VP37 mechanical injection pump. The displacement is 2,497 cc (152.4 cu in) and the compression ratio is 22.0:1.
Some engine variants have an intercooler in addition to the turbocharger; vehicles so equipped can be identified by the designation tds. The M51 has a cast iron block and aluminum head, one chain driven overhead camshaft, and two valves per cylinder. Compared to the M21 the M51 features tappets and hydraulic valve lash adjustment. The fuel injection in the first engines and all E36 models is controlled by the Bosch DDE 2.1, which was replaced after the first technical revision by DDE 2.2, resulting in greater torque at lower revs. For lubrication SAE 5W-40 oil is used.
::data[format=table]
| Version | Power | Torque | Years |
|---|---|---|---|
| M51D25 UL | 115 hp-metric | ||
| at 4800 rpm | 222 Nm | ||
| at 1900 rpm | 1991–1997 | ||
| M51D25 OL | 105 kW | ||
| at 4800 rpm | 260 Nm | ||
| at 2200 rpm | 1991–1996 | ||
| Opel X25DT | 130 hp-metric | ||
| at 4800 rpm | 250 Nm | ||
| at 1400 rpm | 1994–2001 | ||
| M51D25TÜ UL | 115 hp-metric | ||
| at 4800 rpm | 230 Nm | ||
| at 1900 rpm | 1996–1998 | ||
| M51D25TÜ OL | 105 kW | ||
| at 4800 rpm | 280 Nm | ||
| at 2200 rpm | 1996–1998 | ||
| M51D25TÜ OL | 105 kW | ||
| at 4600 rpm | 1998–2000 | ||
| M51D25M1 | 100 kW | ||
| at 4400 rpm | 270 Nm | ||
| at 2300 rpm | 1995-2001 | ||
| :: |
Applications:
- 1991 - 1996 BMW 325td (M51D25 UL)
- 1996 - 1998 BMW 325td (M51D25TÜ UL)
- 1993 - 1996 BMW 325tds (M51D25 OL)
- 1996 - 1998 BMW 325tds (M51D25TÜ OL)
- 1992 - 1996 BMW 525td (M51D25 UL)
- 1991 - 1996 BMW 525tds (M51D25 OL)
- 1996 - 2000 BMW 525tds (M51D25TÜ OL)
- 1996 - 2000 BMW 525td (M51D25TÜ UL)
- 1996 - 2000 BMW 725tds (M51D25TÜ OL)
- 1995 - 2001 Range Rover (P38A)
- 1995 - 2001 Opel Omega B
- 1992 UMM Alter II (single example; engine, gearbox, and electronics were fitted by BMW in Munich)
References
References
- "BMW M41 and M51 Diesel Engines".
- "Vauxhall V94 - Omega B confidential launch guides".
- (July 2025). "Detailed specs review of 1995 Opel Omega 2.5 TD model for Europe".
- "Opel Omega 2.5 TD CD Manual 4 doors specs".
- "Die BMW Turbodiesel".
- "Betriebsanleitung zum Fahrzeug. [BMW 5er Limousine/touring (E39)]".
- [http://www.bimmertoday.de/2012/01/21/die-bmw-sportdiesel-von-524td-e28-uber-530d-e39-bis-m550d-f10/ Die BMW-Sportdiesel: Von 524td E28 über 530d E39 bis BMW M550d F10] (german)
- [http://www.dieseltuning.de/tuning-fuer-alle-motoren/opel/omega/opel-omega-b-2-5-td-96-kw-130-ps-motor-25dt-x25dt-x25td-eco-optimierung-leistungssteigerung/a-1928471149/ Opel Omega B 2.5 TD 96 kW 130 PS - Motor: 25DT, X25DT, X25TD - Eco Optimierung / Leistungssteigerung] {{Webarchive. link. (2016-06-23 (german))
- Etzold: [http://www.delius-klasing.de/sixcms/media.php/9/swg_bmw_5er_leseprobe.pdf So wird's gemacht: pflegen – warten – reparieren. Band 102, BMW 5er E39] {{Webarchive. link. (2017-05-17 Delius Klasing Verlag. Pages 12 and 13 (german))
- [http://www.ultimatespecs.com/de/car-specs/BMW/195/BMW-E38-7-Series-725-tds.html BMW E38 7 Series 725 tds Technical data]
- [http://www.oil-club.ru/wp-content/uploads/2013/01/BMW.pdf Übersicht der Motorölqualitäten]. Page 7 (german)
- [http://www.automobile-catalog.com/car/1997/1398605/range_rover_2_5_dse.html Automobile Catalogue: 1997 Range Rover 2.5 DSE (model for Europe ) specifications & performance data review] {{Webarchive. link. (2016-05-06 .)
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