BMW B48 / B38 vs 2.3 MZR DISI Turbo: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the 2.3 MZR DISI Turbo: 24/100 (low risk) versus 63/100 (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 2.3 MZR DISI Turbo has 2 documented serious faults, the main one being «Timing chain stretch and VVT actuator failure on the 2.3 DISI Turbo».

Risk index

BMW B48 / B38

Low risk · 1 serious fault

Lower risk

Risk index

2.3 MZR DISI Turbo

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 5 October 202610 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 2.3 MZR DISI Turbo reliable?

Mazda's 2.3 DISI Turbo (L3-VDT, 2005-2013) is powerful but demanding: the timing chain, the turbo and oil sludge are its weak points; only buy one with a good oil service history.^[4][5][6]

See the 3 of the 2.3 MZR DISI Turbo faults

Side-by-side comparison

Comparison of BMW B48 / B38 and 2.3 MZR DISI Turbo
Item	BMW B48 / B38	2.3 MZR DISI Turbo
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,998 cm³	2,261 cm³
Timing	Chain	Chain
Power	136–312 hp	256–263 hp
Production	since 2014^[1][7][8]	2005–2013^[4][9]
Reliability
Risk index (what is it?)	24Low risk	63High risk
Documented faults	4	3
Of high or critical severity	1	2
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: Timing chain stretch and VVT actuator failure on the 2.3 DISI Turbo High severity: Premature turbocharger wear from poor lubrication on the 2.3 DISI Turbo Medium severity: Oil consumption and sludge in the 2.3 DISI Turbo engine
Most expensive documented repair	No reliable data	up to €2,200Premature turbocharger wear from poor lubrication on the 2.3 DISI TurboPublished figure^[5]
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][10] B48 2.0 up to 302-312 hp, high performance (MINI John Cooper Works, BMW X1 M35i)^[2]	None
With cautionVersions to be cautious about	None	2.3 MZR DISI Turbo 256-260 hp (L3-VDT, 2005-2009)^[4][5] 2.3 MZR DISI Turbo (L3-VDT, 2010-2013)^[4][5]
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 17 models with the BMW B48 / B38

2.3 MZR DISI Turbo

Other comparisons

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With the 2.3 MZR DISI Turbo

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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
Mazda L engineWikipedia (inglés) · Other source · consulted 5 October 2026
Problemas Mazda CX-7Totalrenting · Other source · consulted 5 October 2026 · in Spanish
2009 Mazda CX-7 engine problemsCarComplaints · Owners' forum · consulted 5 October 2026
BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Mazda CX-7Wikipedia (inglés) · Other source · consulted 5 October 2026
5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026