BMW B38 / B37 vs 1.5 EcoBoost: which engine is more reliable?

According to our risk index, the BMW B38 / B37 carries less risk than the 1.5 EcoBoost: 20/100 (low risk) versus 43/100 (moderate risk). The BMW B38 / B37 has 1 documented serious fault, the main one being «B38 crankshaft thrust bearing failure (units before April 2015)»; the 1.5 EcoBoost has 2 documented serious faults, the main one being «Coolant loss through a microcrack in the engine block (4-cylinder 1.5)».

Risk index

BMW B38 / B37

Low risk · 1 serious fault

Lower risk

Risk index

1.5 EcoBoost

Moderate 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 30 October 202621 sources How we work

Is the BMW B38 / B37 reliable?

BMW and MINI's three-cylinder B38 (petrol) and B37 (diesel) have no serious, widespread documented fault. The only problem reported in the press is the crankshaft thrust bearing on early B38 units (up to April 2015), corrected by BMW. BMW's EGR campaigns affect four- and six-cylinder diesels, not the B37.^[1][2][3]

See the 3 of the BMW B38 / B37 faults

Is the 1.5 EcoBoost reliable?

These are two engines with the same name. The four-cylinder (2014-2019: Mondeo, Focus, Kuga, C-Max) has documented cases of coolant loss through a microcrack in the block, which can end in a new engine. The three-cylinder Dragon (from 2018) has hardly any mechanical faults cited, but the Kuga has been recalled several times because an injector can crack and cause a fuel leak with a fire risk.^[4][5][6][7]

See the 2 of the 1.5 EcoBoost faults

Side-by-side comparison

Comparison of BMW B38 / B37 and 1.5 EcoBoost
Item	BMW B38 / B37	1.5 EcoBoost
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,499 cm³	1,498 cm³
Timing	Chain	Chain
Power	75–231 hp	120–200 hp
Production	since 2014^[8][9][10]	since 2014^{[11][12][13][14][15]}
Reliability
Risk index (what is it?)	20Low risk	43Moderate risk
Documented faults	3	2
Of high or critical severity	1	2
Worst severity	Critical severity	Critical severity
Main faults	Critical severity: B38 crankshaft thrust bearing failure (units before April 2015) Medium severity: Coolant leaks and water pump or thermostat failure on the B38 Low severity: Carbon build-up on the B38's intake valves and injectors	Critical severity: Coolant loss through a microcrack in the engine block (4-cylinder 1.5) Critical severity: Fuel leak from cracked injectors, with a fire risk (Kuga Dragon)
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	B38 1.5 136-140 hp from April 2015 (B38A15 / B38B15)^[1] B37 1.5 diesel 95-116 hp (B37C15K0 / B37C15U0), up to 2017^[16] B37TÜ1 1.5 diesel 95-116 hp (from late 2017)^[17]	None
With cautionVersions to be cautious about	B38 1.2 (B38A12, MINI One)^[9] B38 1.5 136 hp up to April 2015 (B38A15)^[1] B38K15T0 231 hp (BMW i8)^[18]	1.5 EcoBoost 4-cylinder 120/150/160/182 hp (Mondeo, Focus, Kuga, C-Max, S-Max, Galaxy, 2014-2019)^[4][5] 1.5 EcoBoost Dragon 3-cylinder 120/150/182 hp (Kuga III and Focus IV, from 2018)^{[6][7][19][20]} 1.5 EcoBoost ST 200 hp (Fiesta ST 2018-2023 and Puma ST, code YZJA)^[6][13][21]
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 B38 / B37

See the 14 models with the BMW B38 / B37

1.5 EcoBoost

See the 10 models with the 1.5 EcoBoost

Other comparisons

With the BMW B38 / B37

With the 1.5 EcoBoost

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Sources

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

BMW Dreizylinder: Dauertest-Probleme des B38 behoben?BimmerToday · Motoring press · published 5 October 2017 · consulted 4 October 2026 · in German
2024: BMW recall due to EGR coolers extended againcar-recalls.eu · Motoring press · published 28 March 2024 · consulted 4 October 2026
BMW diésel Europa: llamada a revisión por el EGR y riesgo de incendioDiariomotor · Motoring press · consulted 4 October 2026 · in Spanish
Ford Mondeo V - Auto ReviewANWB · Consumer association · published 2 September 2024 · consulted 8 October 2026 · in Dutch
Ford EcoBoost Probleme und Haltbarkeitgebrauchtwagenberater.de · Motoring press · consulted 8 October 2026 · in German
Rückruf: Bei diesen Ford-Modellen besteht BrandgefahrADAC · Motoring press · published 2 February 2026 · consulted 8 October 2026 · in German
Rückruf Ford Kuga: Brandgefahr wegen defekter Einspritzventileauto motor und sport · Motoring press · published 3 May 2024 · consulted 8 October 2026 · in German
BMW B38 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
BMW B38 (Wikipedia, alemán)Wikipedia · Other source · consulted 4 October 2026 · in German
BMW B37 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
Ford EcoBoost engineWikipedia (en) · Other source · consulted 8 October 2026
Ford EcoBoostWikipedia (de) · Other source · consulted 8 October 2026 · in German
Every Ford Powered By The 1.5L EcoBoost 'Dragon'SlashGear · Motoring press · consulted 8 October 2026
Ford Kuga Titanium 1.5 EcoBoost Auto-Start-Stop 150 CV 4x2 (2014-2016): precio y ficha técnicakm77 · Technical documentation · consulted 8 October 2026 · in Spanish
Ford Kuga MK3 2019-2026 Probleme und Schwachstellengebrauchtwagenberater.de · Motoring press · consulted 8 October 2026 · in German
Project one M: MINI Cooper D F56 fährt eine Million Kilometer in 12 JahrenBimmerToday · Motoring press · published 24 June 2026 · consulted 4 October 2026 · in German
BMW Baukasten-Diesel: Mehr Infos zur TÜ1 für B47 und B37BimmerToday · Motoring press · published 20 November 2017 · consulted 4 October 2026 · in German
BMW i8 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
Trois problèmes avec le Ford Kuga : jauge de carburant, injecteurs et toit panoramique défectueuxcar-recalls.eu · Other source · consulted 8 October 2026 · in French
Tous les problèmes sur Ford FOCUS 4 2018 (93 témoignages)fiches-auto.fr · Owners' forum · consulted 8 October 2026 · in French
YZJA engine (Ford 1.5 EcoBoost)Motorinsel · Technical documentation · consulted 8 October 2026