M50 and M52 vs Skyactiv-G: which engine is more reliable?

According to our risk index, the Skyactiv-G carries less risk than the M50 and M52: 25/100 (moderate risk) versus 52/100 (high risk). The M50 and M52 has 2 documented serious faults, the main one being «Cooling system failure (expansion tank, thermostat, pump and radiator)»; the Skyactiv-G has no documented serious faults.

Risk index

M50 and M52

High risk · 2 serious faults

Risk index

Skyactiv-G

Moderate risk · 0 serious faults

Lower risk

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 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).^[1][2][3]

See the 5 of the M50 and M52 faults

Is the Skyactiv-G reliable?

The Skyactiv-G is a naturally aspirated petrol engine that the German specialist press consistently describes as reliable, with no documented pattern of serious engine faults in any Mazda model reviewed. Its weak point, shared with almost any direct-injection petrol engine, is carbon build-up in the intake; in addition, 2017-2020 units had recalls for software and for the fuel pump, since fixed by the manufacturer.^[4][5][6][7]

See the 5 of the Skyactiv-G faults

Side-by-side comparison

Comparison of M50 and M52 and Skyactiv-G
Item	M50 and M52	Skyactiv-G
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	—	—
Timing	Chain	Chain
Power	150–193 hp	75–187 hp
Production	1990–2001^{[8][9][10][11]}	since 2011^[4][12]
Reliability
Risk index (what is it?)	52High risk	25Moderate risk
Documented faults	5	5
Of high or critical severity	2	0
Worst severity	Critical severity	Medium severity
Main faults	High severity: Cooling system failure (expansion tank, thermostat, pump and radiator) Critical severity: Premature cylinder wear (Nikasil coating) Medium severity: Worn VANOS seals	Medium severity: Intake shut-off valve software issue and engine stalling Medium severity: Micro-cracks in the fuel pump impeller Medium severity: ECU programming and loss of power (CX-5 II and Mazda3 IV)
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	None	1.5 Skyactiv-G (P5-VPS)^[5][13] 2.0 Skyactiv-G (PE-VPS)^[6][7][14] 2.5 Skyactiv-G (PY-VPS)^[6]
With cautionVersions to be cautious about	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)^[9][15] M52B25, 2.5 litre (170 hp; 1995-1999)^[9][15] M52B28, 2.8 litre (193 hp; 1995-1999)^[9][15][17] M52TUB20, 2.0 litre (150 hp; 1998-2001)^[8][15] M52TUB25, 2.5 litre (170 hp; 1998-2000)^[8][15] M52TUB28, 2.8 litre (193 hp; 1998-2001)^[3][8][15]	None
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

M50 and M52

Skyactiv-G

See the 9 models with the Skyactiv-G

Other comparisons

With the M50 and M52

With the Skyactiv-G

Compare other engines

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Sources

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

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
SkyactivWikipedia (inglés) · Other source · consulted 27 September 2026
Mazda 3 (BM/BN, 2013-2019) – Erfahrungen & ProblemeGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
Mazda 6 (GJ, III) – Erfahrungen & ProblemeGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
Mazda CX-5 II (KF) – Erfahrungen & ProblemeGebrauchtwagenberater · Motoring press · consulted 27 September 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
List of Mazda enginesWikipedia (inglés) · Other source · consulted 27 September 2026
Mazda 2 (DJ) – Erfahrungen & ProblemeGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
Mazda 3 IV (BP) – Erfahrungen & ProblemeGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
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