BMW B38 / B37 vs M43 1.6, 1.8 and 1.9: which engine is more reliable?

According to our risk index, the BMW B38 / B37 carries less risk than the M43 1.6, 1.8 and 1.9: 20/100 (low risk) versus 42/100 (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 M43 1.6, 1.8 and 1.9 has 1 documented serious fault, the main one being «Failure of the plastic parts in the cooling system».

Risk index

BMW B38 / B37

Low risk · 1 serious fault

Lower risk

Risk index

M43 1.6, 1.8 and 1.9

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 202616 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 M43 1.6, 1.8 and 1.9 reliable?

The M43 (1993-2002) is an 8-valve petrol four-cylinder with a timing chain that Autohints describes as one of BMW’s most durable engines of the nineties. The faults the sources cite are with ancillaries: plastic cooling parts, oil leaks from the gaskets, rough idle, ignition and, in some versions, the DISA valve.^[4][5][6]

See the 5 of the M43 1.6, 1.8 and 1.9 faults

Side-by-side comparison

Comparison of BMW B38 / B37 and M43 1.6, 1.8 and 1.9
Item	BMW B38 / B37	M43 1.6, 1.8 and 1.9
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,499 cm³	—
Timing	Chain	Chain
Power	75–231 hp	102–118 hp
Production	since 2014^[7][8][9]	1993–2002^[5][10][11]
Reliability
Risk index (what is it?)	20Low risk	42Moderate risk
Documented faults	3	5
Of high or critical severity	1	1
Worst severity	Critical severity	High 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	High severity: Failure of the plastic parts in the cooling system Medium severity: DISA intake manifold valve with play and noise Low severity: Oil leaks from gaskets (rocker cover, front cover and crankcase breather)
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^[12] B37TÜ1 1.5 diesel 95-116 hp (from late 2017)^[13]	None
With cautionVersions to be cautious about	B38 1.2 (B38A12, MINI One)^[8] B38 1.5 136 hp up to April 2015 (B38A15)^[1] B38K15T0 231 hp (BMW i8)^[14]	M43B16, 1.6 litre (102 hp; 1993-1999)^[4][5][6] M43B18, 1.8 litre (115 hp; 1993-1999)^[4][15] M43TUB19, 1.9 litre (105 hp; 1998-2002)^[4][6][16] M43TUB19, 1.9 litre (118 hp; 1998-2002)^[4][6][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 B38 / B37

See the 17 models with the BMW B38 / B37

M43 1.6, 1.8 and 1.9

Other comparisons

With the BMW B38 / B37

With the M43 1.6, 1.8 and 1.9

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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
BMW M43B18 1.8L 115hp inline-4 cylinder engineAutoHints · Technical documentation · consulted 2 November 2026
Der BMW M43 Motor: Technische Daten, Probleme, Haltbarkeit & FahrzeuglisteCarWiki.de · Other source · consulted 2 November 2026 · in German
BMW M43: problemas conocidosEnginescope · Other source · consulted 2 November 2026
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
BMW M43Wikipedia (inglés) · Other source · consulted 2 November 2026
BMW M43Wikipedia (alemán) · Other source · consulted 2 November 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
BMW 3 Series E36 Reliability Guide: Everything You Need to Know Before BuyingEuro Premium Parts · Technical documentation · consulted 2 November 2026
316i M43: 17 Jahre, Standhaftigkeit erhöhen (E46)BMW-Syndikat (foro) · Owners' forum · consulted 2 November 2026 · in German