BMW B57 vs 1.8 TDCi: which engine is more reliable?

According to our risk index, the BMW B57 carries less risk than the 1.8 TDCi: 22/100 (low risk) versus 48/100 (moderate risk). The BMW B57 has 3 documented serious faults, the main one being «EGR cooler leaks on the B57 (limited action on the 540d xDrive)»; the 1.8 TDCi has 1 documented serious fault, the main one being «Breakage of the timing belt or of the high-pressure pump's belt (running in oil)».

Risk index

BMW B57

Low risk · 3 serious faults

Lower risk

Risk index

1.8 TDCi

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 4 October 202613 sources How we work

Is the BMW B57 reliable?

The BMW B57 (2015 onwards) is the six-cylinder diesel that succeeded the N57. The sources consulted document no widespread faults: its most cited weak point is the AdBlue/SCR system, and it was left out of the big EGR campaigns that hit the N47 and N57. The timing chain is still at the back, next to the gearbox.^[1][2]

See the 4 of the BMW B57 faults

Is the 1.8 TDCi reliable?

The 1.8 TDCi (codename Lynx) was Ford's standard diesel between 2001 and 2014, with Delphi common-rail injection and a variable-geometry turbo. It is an engine with well-documented faults: the dual-mass flywheel and clutch are by far its weakest point, followed by the injectors, the EGR valve and, to a lesser extent, the turbo hoses and the timing drive itself.^[3][4][5][6]

See the 5 of the 1.8 TDCi faults

Side-by-side comparison

Comparison of BMW B57 and 1.8 TDCi
Item	BMW B57	1.8 TDCi
Technical data
Type	Engine	Engine
Fuel	Diesel	Diesel
Displacement	2,993 cm³	1,753 cm³
Timing	Chain	Timing belt (dry)
Power	265–400 hp	75–125 hp
Production	since 2015^[7][8]	2001–2014^[3][9][10]
Reliability
Risk index (what is it?)	22Low risk	48Moderate risk
Documented faults	4	5
Of high or critical severity	3	1
Worst severity	High severity	Critical severity
Main faults	Medium severity: AdBlue/SCR system fault (NOx sensors, heater and pump) High severity: EGR cooler leaks on the B57 (limited action on the 540d xDrive) High severity: Timing chain wear on the gearbox side	Critical severity: Breakage of the timing belt or of the high-pressure pump's belt (running in oil) Medium severity: Premature wear of the dual-mass flywheel and clutch Medium severity: Delphi injector failure (leaks, cracks or poor spray pattern)
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	B57D30 265 hp, single turbo (B57D30O0, 2015-2020)^[1] B57D30 286-340 hp, twin turbo with 48 V (B57D30O2/T2, 2020 onwards)^[1]	None
With cautionVersions to be cautious about	B57D30 320 hp, twin turbo (B57D30T0, 2015-2020)^[1] B57D30 400 hp, four turbos (B57D30S0, 2016-2020)^[1]	1.8 TDCi 75/90/100 (entry-level tunes: Focus I and Transit Connect)^[4][5] 1.8 TDCi 110/115/125 (Focus II, C-Max, Mondeo, Galaxy, S-Max and Transit Connect)^{[4][5][6][11][12][13]}
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 B57

See the 9 models with the BMW B57

1.8 TDCi

See the 8 models with the 1.8 TDCi

Other comparisons

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With the 1.8 TDCi

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Sources

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

Motor BMW B57: fiabilidad y averíasDasercars · Motoring press · consulted 4 October 2026 · in Spanish
Motor BMW N57: diferencias con el B57Dasercars · Motoring press · consulted 4 October 2026 · in Spanish
Ford Duratorq engineWikipedia · Other source · consulted 27 September 2026
Fiabilité et pannes du Ford Mondeo 3 (1.8 TDCi 125ch)Fiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Fiabilité et pannes du Ford Focus 2 (1.8 TDCi 115ch)Fiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Fiabilité et pannes du Ford S-MaxFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
BMW B57 (Wikipedia en)Wikipedia · Other source · consulted 4 October 2026
BMW B57 (Wikipedia de)Wikipedia · Other source · consulted 4 October 2026 · in German
Ford FocusWikipedia · Other source · consulted 27 September 2026 · in Spanish
Ford Transit ConnectWikipedia · Other source · consulted 27 September 2026 · in Spanish
Ford Focus Mk2: Probleme und SchwachstellenGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
Ford Mondeo Mk4: Probleme und SchwachstellenGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
Ford S-Max: Probleme und KrankheitenGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German