BMW M51

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.<ref name="carspecs" /><ref name="Bimmertoday" /><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name="Bimmertoday" /> The M51 has a cast iron block and aluminum head, one chain driven overhead camshaft,<ref name="Etzold" /> and two valves per cylinder.<ref name="Bimmertoday" /><ref name="Etzold" /> Compared to the M21 the M51 features tappets and hydraulic valve lash adjustment.<ref name="Bimmertoday" /> 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,<ref name="Etzold" /> resulting in greater torque at lower revs.<ref name="Etzold" /> For lubrication SAE 5W-40 oil is used.<ref name="öl" />

Version	Power	Torque	Years
M51D25 UL	Template:Cvt at 4800 rpm	Template:Convert at 1900 rpm	1991–1997
M51D25 OL	Template:Cvt at 4800 rpm	Template:Convert at 2200 rpm	1991–1996
Opel X25DTTemplate:Efn	Template:Cvt at 4800 rpm<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref><ref name="tuning" /><ref>{{#invoke:citation/CS1|citation	CitationClass=web }}Template:Dead link</ref><ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> || Template:Convert at 1400 rpm || 1994–2001
M51D25TÜ UL	Template:Cvt at 4800 rpm<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> || Template:Convert at 1900 rpm || 1996–1998
M51D25TÜ OL	Template:Cvt at 4800 rpm<ref name="Etzold" />	Template:Convert at 2200 rpm	1996–1998
M51D25TÜ OL	Template:Cvt at 4600 rpm<ref name="Etzold" />		1998–2000
M51D25M1Template:Efn	Template:Cvt at 4400 rpm<ref name="rangerover" />	Template:Convert 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)

See also

• List of BMW engines

References

<references> <ref name="Bimmertoday">Die BMW-Sportdiesel: Von 524td E28 über 530d E39 bis BMW M550d F10 (german)</ref> <ref name="tuning">Opel Omega B 2.5 TD 96 kW 130 PS - Motor: 25DT, X25DT, X25TD - Eco Optimierung / Leistungssteigerung Template:Webarchive (german)</ref> <ref name="Etzold">Etzold: So wird's gemacht: pflegen – warten – reparieren. Band 102, BMW 5er E39 Template:Webarchive Delius Klasing Verlag. Pages 12 and 13 (german)</ref> <ref name="carspecs">BMW E38 7 Series 725 tds Technical data</ref> <ref name="öl">Übersicht der Motorölqualitäten. Page 7 (german)</ref> <ref name="rangerover">Automobile Catalogue: 1997 Range Rover 2.5 DSE (model for Europe ) specifications & performance data review Template:Webarchive.</ref> </references> Template:BMW automotive diesel engines: 1980s to 2000s