BMW B58 vs M50 and M52: which engine is more reliable?

According to our risk index, the BMW B58 carries less risk than the M50 and M52: 38/100 (moderate risk) versus 52/100 (high risk). The BMW B58 has 1 documented serious fault, the main one being «Failure of the oil pump with a plastic rotor housing»; the M50 and M52 has 2 documented serious faults, the main one being «Cooling system failure (expansion tank, thermostat, pump and radiator)».

Risk index

BMW B58

Moderate risk · 1 serious fault

Lower risk

Risk index

M50 and M52

High risk · 2 serious faults

The index (0–100) weights the severity and frequency of the three most serious documented faults. How it is calculated

Reviewed on 2 November 202617 sources How we work

Is the BMW B58 reliable?

The B58 (3.0 turbo straight-six, since 2015) is considered robust and less troublesome than the N54/N55 it replaced, and the sources do not document widespread internal failures. The known faults are on the periphery: the plastic oil filter housing, crankcase ventilation, gaskets and coolant. On units built before 2021 there are also US reports of an oil pump with a plastic housing.^[1][2][3][4]

See the 6 of the BMW B58 faults

Is the M50 and M52 reliable?

The M52 and its predecessor the M50 are six-cylinder petrol engines that the sources describe as durable: Enginescope considers 300,000 km routine with the cooling circuit looked after. Watch the plastic cooling parts, VANOS, crankcase ventilation and oil leaks and, in the aluminium-block M52s built from 1995 to March 1998, cylinder wear caused by sulphur (Nikasil).^[5][6][7]

See the 5 of the M50 and M52 faults

Side-by-side comparison

Comparison of BMW B58 and M50 and M52
Item	BMW B58	M50 and M52
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	2,998 cm³	—
Timing	Chain	Chain
Power	290–441 hp	150–193 hp
Production	since 2015^[8][9]	1990–2001^{[10][11][12][13]}
Reliability
Risk index (what is it?)	38Moderate risk	52High risk
Documented faults	6	5
Of high or critical severity	1	2
Worst severity	High severity	Critical severity
Main faults	High severity: Failure of the oil pump with a plastic rotor housing Medium severity: Oil and coolant leak from the plastic oil filter housing Medium severity: Failure of the crankcase ventilation PCV valve (integrated in the valve cover)	High severity: Cooling system failure (expansion tank, thermostat, pump and radiator) Critical severity: Premature cylinder wear (Nikasil coating) Medium severity: Worn VANOS seals
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	B58TU2 381 hp (B58B30M2, since 2022)^[2][3]	None
With cautionVersions to be cautious about	B58 326 hp (B58B30M0, 2015-2019)^[2][3][14] B58 340-360 hp (B58B30M0, 2016-2019)^[2][3][14] B58TU 333-340 hp (B58B30M1, since 2018)^[2][3] B58TU 374 hp (B58B30O1, M340i, M440i and M240i, since 2019)^[3]	M50B20, 2.0 litre (150 hp; 1990-1995)^[15][16] M50B25, 2.5 litre (192 hp; 1990-1995)^[15][16] M52B20, 2.0 litre (150 hp; 1994-1999)^[11][15] M52B25, 2.5 litre (170 hp; 1995-1999)^[11][15] M52B28, 2.8 litre (193 hp; 1995-1999)^[11][15][17] M52TUB20, 2.0 litre (150 hp; 1998-2001)^[10][15] M52TUB25, 2.5 litre (170 hp; 1998-2000)^[10][15] M52TUB28, 2.8 litre (193 hp; 1998-2001)^[7][10][15]
AvoidVersions to avoid	None	None

Severity of each fault: green, low; amber, medium; red, high; dark red, critical. How we rate them

Cars that each one is fitted to

BMW B58

See the 16 models with the BMW B58

M50 and M52

Other comparisons

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With the M50 and M52

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Sources

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

The 5 Most Common BMW B58 Engine ProblemsBMW Tuning · Technical documentation · published 7 February 2020 · consulted 9 October 2026
BMW B58 EngineFCP Euro · Technical documentation · consulted 9 October 2026
The Popular BMW B58 Inline-Six Engine Has One Big Achilles HeelThe Autopian · Motoring press · published 14 June 2024 · consulted 9 October 2026
¿En qué se diferencian los motores B58 y S58 de BMW?Diariomotor · Motoring press · published 27 April 2024 · consulted 9 October 2026 · in Spanish
BMW 3 Series E36 320i (M52B20): reliabilityEnginescope · Other source · consulted 2 November 2026
BMW M52 reliabilityAutoscore · Other source · consulted 2 November 2026
BMW M52 Engine: Performance, Reliability, and TuningBMWBlog · Motoring press · consulted 2 November 2026
BMW B58Wikipedia (inglés) · Other source · consulted 9 October 2026
BMW B58Wikipedia (alemán) · Other source · consulted 9 October 2026 · in German
BMW M52Wikipedia (inglés) · Other source · consulted 2 November 2026
BMW M52Wikipedia (alemán) · Other source · consulted 2 November 2026 · in German
BMW M50Wikipedia (inglés) · Other source · consulted 2 November 2026
BMW M50Wikipedia (alemán) · Other source · consulted 2 November 2026 · in German
How A Plastic Part On BMW's B58 Engine Can Turn An Oil Change Into A $3,000 RepairThe Autopian · Motoring press · published 28 March 2025 · consulted 9 October 2026
BMW M50 / M52: problemas conocidosEnginescope · Other source · consulted 2 November 2026
Der BMW M50 Motor: Technische Daten, Probleme, Haltbarkeit & FahrzeuglisteCarWiki.de · Other source · consulted 2 November 2026 · in German
BMW Z3 Reliability Guide: Everything You Need to Know Before BuyingEuro Premium Parts · Technical documentation · consulted 2 November 2026