BMW B48 / B38 vs 1.4 and 1.6 TU3/TU5: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the 1.4 and 1.6 TU3/TU5: 24/100 (low risk) versus 36/100 (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 1.4 and 1.6 TU3/TU5 has 1 documented serious fault, the main one being «Head gasket damaged after overheating».

Risk index

BMW B48 / B38

Low risk · 1 serious fault

Lower risk

Risk index

1.4 and 1.6 TU3/TU5

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 27 September 202616 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 1.4 and 1.6 TU3/TU5 reliable?

The TU is one of PSA's most widely built petrol engines: more than 15.6 million units between 1986 and 2014. It is simple (no turbo, no direct injection or particulate filter, belt-driven timing) and has a reputation for durability. The faults owners cite most are cheap wear parts -ignition coils, sensors and thermostat- and not block failures or cylinder head design flaws.^[4][5][6][7]

See the 5 of the 1.4 and 1.6 TU3/TU5 faults

Side-by-side comparison

Comparison of BMW B48 / B38 and 1.4 and 1.6 TU3/TU5
Item	BMW B48 / B38	1.4 and 1.6 TU3/TU5
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,998 cm³	—
Timing	Chain	Timing belt (dry)
Power	136–312 hp	75–112 hp
Production	since 2014^[1][8][9]	1986–2014^[4][10][11]
Reliability
Risk index (what is it?)	24Low risk	36Moderate risk
Documented faults	4	5
Of high or critical severity	1	1
Worst severity	High severity	High 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	High severity: Head gasket damaged after overheating Medium severity: Ignition coils that fail and cause jerking Medium severity: Thermostat stuck open or closed
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][12] B48 2.0 up to 302-312 hp, high performance (MINI John Cooper Works, BMW X1 M35i)^[2]	TU3 1.4 75 hp 8v (TU3JP/TU3KFX, 1994-2014)^[5][6] TU5 1.6 88-90 hp 8v (TU5JP, from 1994)^[11][13] TU5 1.6 16v 109-112 hp (TU5JP4/TU5NFU, from 2000)^[5][6][7]
With cautionVersions to be cautious about	None	TU9 1.0 and TU1 1.1 (954 and 1,124 cc, 45-60 hp, 1986-2014)^[14][15][16]
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 20 models with the BMW B48 / B38

1.4 and 1.6 TU3/TU5

See the 14 models with the 1.4 and 1.6 TU3/TU5

Other comparisons

With the BMW B48 / B38

With the 1.4 and 1.6 TU3/TU5

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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
Moteur PSA TUWikipédia (francés) · Other source · consulted 27 September 2026 · in French
Tous les problèmes sur Peugeot 206 (témoignages)Fiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Tous les problèmes sur Peugeot 307 (témoignages)Fiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Tous les problèmes sur Citroën Xsara (témoignages)Fiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
PSA TU engineWikipedia (inglés) · Other source · consulted 27 September 2026
Peugeot 206Wikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
Citroën XsaraWikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
Fiabilité Citroën Saxo (1996-2003) : pannes et témoignagesFiches-auto.fr · Owners' forum · consulted 2 November 2026 · in French
Fiabilité Peugeot 106 (1991-2003) : pannes et témoignagesFiches-auto.fr · Owners' forum · consulted 2 November 2026 · in French
Quelle citadine d'occasion choisir ?L'argus · Motoring press · consulted 2 November 2026 · in French