BMW B38 / B37 vs Rover K-Series: which engine is more reliable?

According to our risk index, the BMW B38 / B37 carries less risk than the Rover K-Series: 20/100 (low risk) versus 46/100 (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 Rover K-Series has 2 documented serious faults, the main one being «Head gasket failure».

Risk index

BMW B38 / B37

Low risk · 1 serious fault

Lower risk

Risk index

Rover K-Series

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 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 Rover K-Series reliable?

The Rover K-Series has one very well-known fault: the head gasket, which according to Diariomotor can fail at under 100,000 km and which technical sources link to a small cooling circuit and a badly placed thermostat. The usual repair uses the multi-layer (MLS) gasket developed for the Freelander; the other two documented faults (sunken liners and coolant leaks) are related to that same circuit.^[4][5][6][7]

See the 3 of the Rover K-Series faults

Side-by-side comparison

Comparison of BMW B38 / B37 and Rover K-Series
Item	BMW B38 / B37	Rover K-Series
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,499 cm³	—
Timing	Chain	Timing belt (dry)
Power	75–231 hp	60–160 hp
Production	since 2014^[8][9][10]	1990–2005^[5][11]
Reliability
Risk index (what is it?)	20Low risk	46Moderate risk
Documented faults	3	3
Of high or critical severity	1	2
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: Head gasket failure High severity: Sunken cylinder liners and warped head after overheating Medium severity: Coolant leaks: expansion tank cap, rear block rail and hoses
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)^[9] B38 1.5 136 hp up to April 2015 (B38A15)^[1] B38K15T0 231 hp (BMW i8)^[14]	1.1 K8 60 hp / K16 75 hp (Rover 25, 1998-2005)^[4][7] 1.4 8V/16V 74-103 hp (14K2F / 14K4F, 1995-2005)^[4][6] 1.6 16V 109-116 hp (16K4F, 1995-2005)^[4][6] 1.8 16V 117-136 hp (18K4F, 1995-2005)^[4][6][15] 1.8 VVC 145-160 hp (18K4K, 1995-2005)^[15][16] 1.8 T turbo 150-160 hp (18K4T, 2002-2005)^[4][7]
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

Rover K-Series

See the 12 models with the Rover K-Series

Other comparisons

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With the Rover K-Series

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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
Guía de compra del MG TF de segunda manoDiariomotor · Motoring press · published 7 November 2023 · consulted 8 October 2026 · in Spanish
MG TF (2002)Wikipedia (en) · Other source · consulted 8 October 2026
Choosing the correct K Series Head Gasket KitDMGRS · Technical documentation · consulted 8 October 2026
Cooling and heating (K-Series: ZR, ZS, ZT, MGF, TF)MGOC Spares · Technical documentation · consulted 8 October 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
Rover K-series engineWikipedia (en) · Other source · consulted 8 October 2026
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
MG ZR ZS ZT & Modern Engine & FuelMGOC Spares · Technical documentation · consulted 8 October 2026
MGF & TF Headgasket Repair KitsMGOC Spares · Technical documentation · consulted 8 October 2026