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M52B20

M52B20, 2.0 litre (150 hp; 1994-1999) engine: faults and reliability

BMW M50 and M52 (seis cilindros en línea de gasolina, 2.0 / 2.5 / 2.8) version

With caution

Durable if maintained, but check that it is not one of the Nikasil M52s built between 1995 and March 1998 and that the cooling circuit has been renewed.[1][2]

Years
1994–1999
Power
150 hp
Faults that affect it
5
2 of high or critical severity
Cars that use it
2
in our database

7 sourcesHow we work

What changes in this version

Successor to the M50, introduced in September 1994 in the 320i E36 and 520i E39: 110 kW (150 hp) and 190 N·m, closed-deck aluminium block about 22.7 kg lighter than the M50’s cast-iron one, cylinders with Nikasil coating and VANOS on the inlet side only.[2][3][4]

Engine codes of this version: M52B20.

Faults of the M52B20 engine

The documented engine faults that affect this version and its years, from most to least important.

  1. 1High severityFrequency: CommonCoolingCooling system failure (expansion tank, thermostat, pump and radiator)The most cited weak point of the M52: the expansion tank, the thermostat housing, the pump impeller and the radiator tanks are plastic and crack with age. If coolant is lost and the engine overheats, the cylinder head can be damaged.Appears at around 97,000 km
  2. 2Critical severityFrequency: OccasionalCylinder head and blockPremature cylinder wear (Nikasil coating)Some aluminium-block M52s with Nikasil-coated cylinders, built between 1995 and March 1998, suffered premature wear from sulphur in the fuel and lost compression. BMW moved to iron liners in 1998, and the M52TU had them as standard.
  3. 3Medium severityFrequency: CommonTimingWorn VANOS sealsVANOS, the M52’s variable valve timing, loses sealing when its internal seals harden: rough idle, lack of low-rev pull and higher consumption appear. It is repaired with a seal kit, but special tools are needed.Appears at around 97,000 km
  4. 4Medium severityFrequency: CommonLubricationOil leaks from the rocker cover, oil filter housing and other gasketsWith age the M52’s rubber gaskets harden: the most cited are the rocker cover gasket and the oil filter housing gasket, and on some M52TUs the plastic cover itself cracks. They should be watched so the oil level does not drop.
  5. 5Medium severityFrequency: OccasionalLubricationBlocked crankcase ventilation valve (CCV) and oil consumptionThe crankcase ventilation valve (CCV) and its hoses clog or break over the years: the engine uses more oil, the idle becomes rough and vacuum leaks can appear. Enginescope sees it mostly on the M52TU.Appears at around 130,000 km

Cars fitted with the M52B20 engine

Open each car to see all its faults with this engine and what to check before buying it.

BMW

Frequently asked questions

Is the M52B20 engine reliable?

Our verdict is “With caution”. Durable if maintained, but check that it is not one of the Nikasil M52s built between 1995 and March 1998 and that the cooling circuit has been renewed.[1][2]

What faults does the M52B20 engine have?

The documented ones that affect this version, by importance: cooling system failure (expansion tank, thermostat, pump and radiator) (high severity), premature cylinder wear (Nikasil coating) (critical severity), worn VANOS seals (medium severity), oil leaks from the rocker cover, oil filter housing and other gaskets (medium severity) and blocked crankcase ventilation valve (CCV) and oil consumption (medium severity).

Which cars use the M52B20 engine?

BMW Serie 3 E36 (1990–2000) and BMW Serie 5 E39 (1995–2001).[2][4][5][6][7]

Are you buying a car with the M52B20 engine?

We will put you in touch with a partner only if you authorise it in the form.

Do you have a car with this engine? Tell us which faults you have had and at how many kilometres. Report your fault.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. BMW M50 / M52: problemas conocidosEnginescope · Other source · consulted 2 November 2026
  2. BMW M52Wikipedia (alemán) · Other source · consulted 2 November 2026 · in German
  3. BMW M52Wikipedia (inglés) · Other source · consulted 2 November 2026
  4. Der BMW M52 Motor: Technische Daten, Probleme, Haltbarkeit & FahrzeuglisteCarWiki.de · Other source · consulted 2 November 2026 · in German
  5. BMW E36: motores y periodos de fabricaciónWikipedia (alemán) · Other source · consulted 2 November 2026 · in German
  6. Der BMW M50 Motor: Technische Daten, Probleme, Haltbarkeit & FahrzeuglisteCarWiki.de · Other source · consulted 2 November 2026 · in German
  7. BMW 5 Series (E39): motores de gasolina y añosWikipedia (inglés) · Other source · consulted 2 November 2026