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BMW B48 / B38 vs Porsche M96/M97: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the Porsche M96/M97: 24/100 (low risk) versus 50/100 (high 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 M96/M97 has 4 documented serious faults, the main one being «Failure of the intermediate shaft bearing (IMS) on the M96/M97».

Risk index

BMW B48 / B38

24

Low risk · 1 serious fault

Lower risk

Risk index

Porsche M96/M97

50

High risk · 4 serious faults

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

23 sourcesHow 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 M96/M97 reliable?

It depends on the version: the M96/M97 has a reputation as a fragile engine because of the IMS bearing, scored cylinders and the rear crankshaft seal, but sources disagree on how many fail and none gives a verified statistic. The most exposed are the 986 and 996 from 1999-2005; the 997.2 and 987.2 from 2009 left this behind with the MA1 engine.[4][5][6][7]

See the 9 of the Porsche M96/M97 faults

Side-by-side comparison

Comparison of BMW B48 / B38 and Porsche M96/M97
BMW B48 / B38Porsche M96/M97
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,998 cm³—
TimingChainChain
Power136–312 hp204–355 hp
Productionsince 2014[1][8][9]1996–2008[4][5][10][11][12][13][14]
Reliability
Risk index (what is it?)24Low risk50High risk
Documented faults49
Of high or critical severity14
Worst severityHigh severityCritical severity
Main faults
  1. Medium severity: Deterioration of hoses and seals in the cooling circuit, with coolant loss
  2. Medium severity: Oil leaks or seepage from seals and covers, near the turbo and the VANOS
  3. High severity: Timing chain on the early units (2014-2018), redesigned in the B48TU
  1. Critical severity: Failure of the intermediate shaft bearing (IMS) on the M96/M97
  2. Critical severity: Scored cylinders (bore scoring) and ‘Kolbenkipper’ on the M96/M97
  3. Critical severity: Porous blocks and cracked or displaced liners in the first M96s
Most expensive documented repairNo reliable dataNo 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]
None
With cautionVersions to be cautious aboutNone
  • 2.5 Boxster 204 hp (M96.20, 1996-1999)[16][17]
  • 2.7 and 3.2 S Boxster 220-258 hp (M96.21/.22/.23/.24, 1999-2004)[5][16]
  • 3.4 Carrera 300 hp (M96.01/.02/.04, 1997-2001)[5][18][19]
  • 3.6 Carrera 320 hp (M96.03, 2002-2005)[5][20]
  • 3.6 and 3.8 S of the 997.1, 325-355 hp (M96.05 / M97.01, 2004-2008)[6][14][21]
  • 2.7, 3.2 S and 3.4 S of the 987.1, 240-295 hp (M96.26 / M97.21 / M97.22, 2004-2008)[22][23]
AvoidVersions to avoidNoneNone

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 M96/M97

Other comparisons

With the BMW B48 / B38

With the Porsche M96/M97

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.

  1. BMW B48Wikipedia (inglés) · Other source · consulted 27 September 2026
  2. Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
  3. BMW Reliability Has Changed, But the Internet Hasn't Caught UpBMWBLOG · Other source · published January 2026 · consulted 27 September 2026
  4. Porsche 996Wikipedia · Other source · consulted 2 November 2026
  5. What are the most common 996 Issues?Flat Six Innovations · Other source · published 23 November 2025 · consulted 2 November 2026
  6. Porsche 911: 5 Generationen im Gebrauchtwagen-CheckAUTO BILD · Motoring press · published 22 September 2026 · consulted 2 November 2026 · in German
  7. Differences between M96 and M97 enginesFlat Six Innovations · Other source · published 25 November 2025 · consulted 2 November 2026
  8. BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
  9. BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  10. Porsche Boxster (986)Wikipedia · Other source · consulted 2 November 2026
  11. List of Porsche enginesWikipedia · Other source · consulted 2 November 2026
  12. Porsche 997Wikipedia (alemán) · Other source · consulted 2 November 2026 · in German
  13. Porsche Boxster and Cayman (987)Wikipedia · Other source · consulted 2 November 2026
  14. The Definitive Guide To Porsche 997 Engines (M96.05, M97, MA1)FCP Euro · Other source · published 16 January 2024 · consulted 2 November 2026
  15. 5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
  16. 1st Generation Porsche Boxster 986 Buyer's GuideStuttcars.com · Motoring press · consulted 2 November 2026
  17. Porsche Boxster (986) 1996-2004: Stärken und Schwächenauto motor und sport · Motoring press · published 6 March 2021 · consulted 2 November 2026 · in German
  18. Porsche 996 (1997-2006) Kaufberatung: Stärken & Schwächenauto motor und sport · Motoring press · published 11 December 2018 · consulted 2 November 2026 · in German
  19. 996 Buyer's GuideRennsportKC · Other source · published 10 March 2011 · consulted 2 November 2026
  20. Porsche 911 996 Buying GuideMotorious · Motoring press · published 17 October 2018 · consulted 2 November 2026
  21. Porsche 911 Common Problems: Every Generation, Every Major IssueRenn Driver · Other source · published 4 May 2026 · consulted 2 November 2026
  22. Porsche Boxster (987) Buyer's GuideGoodwood Classic Solutions · Motoring press · published 1 March 2024 · consulted 2 November 2026
  23. Porsche Cayman and Boxster Common Problems: A Specialist Field GuideForeign Automotive · Other source · consulted 2 November 2026