BMW B48 / B38 vs Porsche MA1 / 9A1: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the Porsche MA1 / 9A1: 24/100 (low risk) versus 25/100 (moderate risk). The BMW B48 / B38 has 1 documented serious fault, the main one being «Timing chain on the early units (2014-2018), redesigned in the B48TU»; the Porsche MA1 / 9A1 has 1 documented serious fault, the main one being «Bore scoring in the MA1 of the 997.2 and 987.2: uncommon, but documented».

Risk index

BMW B48 / B38

Low risk · 1 serious fault

Lower risk

Risk index

Porsche MA1 / 9A1

Moderate risk · 1 serious fault

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 B48 / B38 reliable?

The BMW B48 (2.0 turbo, from 2014) and its three-cylinder sibling, the B38 (1.5), have a reputation as reliable engines within BMW's modern range: there is no serious, widespread fault on record, unlike the timing chain on the N47 diesel or the EGR fire risk on the B47. Keep an eye on the cooling circuit, the oil seals near the turbo and the VANOS, and the carbon build-up typical of direct injection; BMW revised the timing chain in 2018 (B48TU update).^[1][2][3]

See the 4 of the BMW B48 / B38 faults

Is the Porsche MA1 / 9A1 reliable?

Yes, it is noticeably more reliable than the M96/M97: it eliminated the intermediate shaft with its IMS bearing and, according to FCP Euro, the connecting rod bolt failures. What is documented is minor: carbon build-up on the intake valves caused by direct injection, coolant pump leaks on the 991.1 and, rarely, bore scoring on the 997.2.^[4][5][6][7]

See the 3 of the Porsche MA1 / 9A1 faults

Side-by-side comparison

Comparison of BMW B48 / B38 and Porsche MA1 / 9A1
Item	BMW B48 / B38	Porsche MA1 / 9A1
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,998 cm³	—
Timing	Chain	Chain
Power	136–312 hp	255–400 hp
Production	since 2014^[1][8][9]	2009–2016^{[4][7][10][11][12][13][14]}
Reliability
Risk index (what is it?)	24Low risk	25Moderate risk
Documented faults	4	3
Of high or critical severity	1	1
Worst severity	High severity	Critical severity
Main faults	Medium severity: Deterioration of hoses and seals in the cooling circuit, with coolant loss Medium severity: Oil leaks or seepage from seals and covers, near the turbo and the VANOS High severity: Timing chain on the early units (2014-2018), redesigned in the B48TU	Critical severity: Bore scoring in the MA1 of the 997.2 and 987.2: uncommon, but documented Medium severity: Carbon build-up on the intake valves caused by direct injection Medium severity: Leaks from the electronically controlled coolant pumps of the 991.1 and the plastic water pump
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	B38 1.5 136 hp (MINI Cooper, 118i)^[2] B48 2.0 178-197 hp (120i, 220i, 320i, 520i, X1/X2/X3 20i, MINI Cooper S)^[2] B48 2.0 252-258 hp (330i, 530i, X3/X4 xDrive30i)^[2][15] B48 2.0 up to 302-312 hp, high performance (MINI John Cooper Works, BMW X1 M35i)^[2]	3.6 Carrera 345 hp (MA1.02, 2009-2012)^[4][6][7] 3.8 Carrera S 385 hp (MA1.01, 2009-2012)^[6][7] 2.9 Boxster/Cayman 255-265 hp (MA1.20, 2009-2012, no direct injection)^[5][10]
With cautionVersions to be cautious about	None	3.4 Boxster S / Cayman S 310-320 hp (MA1.21/.22, 2009-2012, direct injection)^[5][16] 3.4 Carrera 350 hp (MA1.04, 2011-2015)^[6] 3.8 Carrera S 400 hp (MA1.03, 2011-2015)^[6] 2.7 Boxster/Cayman 265-275 hp (MA1.22, 2012-2016)^[16][17] 3.4 Boxster S / Cayman S / GTS 315-340 hp (MA1.23, 2012-2016)^[16][17]
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 B48 / B38

See the 21 models with the BMW B48 / B38

Porsche MA1 / 9A1

Other comparisons

With the BMW B48 / B38

With the Porsche MA1 / 9A1

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Sources

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

BMW B48Wikipedia (inglés) · Other source · consulted 27 September 2026
Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
BMW Reliability Has Changed, But the Internet Hasn't Caught UpBMWBLOG · Other source · published January 2026 · consulted 27 September 2026
The Definitive Guide To Porsche 997 Engines (M96.05, M97, MA1)FCP Euro · Other source · published 16 January 2024 · consulted 2 November 2026
Porsche 987: The Cayman and Boxster Generation GuideRenn Driver · Other source · published 1 November 2026 · consulted 2 November 2026
Porsche 911: 5 Generationen im Gebrauchtwagen-CheckAUTO BILD · Motoring press · published 22 September 2026 · consulted 2 November 2026 · in German
Porsche 997Wikipedia · Other source · consulted 2 November 2026
BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Porsche Boxster and Cayman (987)Wikipedia · Other source · consulted 2 November 2026
Porsche 991Wikipedia · Other source · consulted 2 November 2026
Porsche Boxster and Cayman (981)Wikipedia · Other source · consulted 2 November 2026
Differences between M96 and M97 enginesFlat Six Innovations · Other source · published 25 November 2025 · consulted 2 November 2026
List of Porsche enginesWikipedia · Other source · consulted 2 November 2026
5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
Porsche Cayman and Boxster Common Problems: A Specialist Field GuideForeign Automotive · Other source · consulted 2 November 2026
Porsche 981: The Cayman and Boxster Generation GuideRenn Driver · Other source · consulted 2 November 2026