1.7 CDTI vs 1.9 dCi: which engine is more reliable?

According to our risk index, the 1.7 CDTI carries less risk than the 1.9 dCi: 36/100 (moderate risk) versus 67/100 (high risk). The 1.7 CDTI has 3 documented serious faults, the main one being «Dual-mass flywheel and clutch wear»; the 1.9 dCi has 3 documented serious faults, the main one being «Seizure and wear of the big-end bearings».

Risk index

1.7 CDTI

Moderate risk · 3 serious faults

Lower risk

Risk index

1.9 dCi

High risk · 3 serious faults

The index (0–100) weights the severity and frequency of the three most serious documented faults. How it is calculated

Reviewed on 27 September 202617 sources How we work

Is the 1.7 CDTI reliable?

The 1.7 CDTI (Isuzu, 2003-2015) is a simple, widely used diesel, but it has built up accounts of soot-fouled EGR valves and injectors, a clogged diesel particulate filter (DPF) with oil dilution, wear of the dual-mass flywheel and clutch, and of the Hitachi-brand alternator; it also requires the timing belt to be changed every 150,000 km or 6 years to avoid a serious failure.^{[1][2][3][4][5][6][7]}

See the 5 of the 1.7 CDTI faults

Is the 1.9 dCi reliable?

The 1.9 dCi (F9Q) was Renault's first common-rail diesel (1999) and powered a large part of its range, and those of Nissan and Volvo, for more than a decade. It has well-documented weak points: on versions of up to 120 hp built before 2005, the big-end bearings can seize and the turbo tends to degrade around 150,000 km; the injectors, the EGR valve and, on the 120 hp versions, the dual-mass flywheel also fail fairly often.^{[8][9][10][11][12]}

See the 5 of the 1.9 dCi faults

Side-by-side comparison

Comparison of 1.7 CDTI and 1.9 dCi
Item	1.7 CDTI	1.9 dCi
Technical data
Type	Engine	Engine
Fuel	Diesel	Diesel
Displacement	1,686 cm³	1,870 cm³
Timing	Timing belt (dry)	Timing belt (dry)
Power	100–130 hp	80–130 hp
Production	2003–2015^[1][13][14]	1999–2011^[15][16][17]
Reliability
Risk index (what is it?)	36Moderate risk	67High risk
Documented faults	5	5
Of high or critical severity	3	3
Worst severity	Critical severity	Critical severity
Main faults	High severity: Dual-mass flywheel and clutch wear High severity: Clogged diesel particulate filter (DPF) and oil dilution Critical severity: Timing belt: risk of serious failure if not changed on time	Critical severity: Seizure and wear of the big-end bearings High severity: Premature turbocharger wear High severity: Failures of the Delphi direct-injection injectors
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	None	None
With cautionVersions to be cautious about	1.7 CDTI 100-101 hp (Z17DTH, 2003-2007)^[6][7] 1.7 CDTI 110 hp (Z17DTJ/A17DTJ/A17DTC/A17DTE, 2007-2014)^[6][7] 1.7 CDTI 125 hp (Z17DTR/A17DTR, 2006-2013)^[2][3] 1.7 CDTI 130 hp (A17DTS, 2010-2015)^[6][7]	1.9 dCi 95-120 (F9Q, first generation, 1999-2005)^[10] 1.9 dCi 125-130 (F9Q, Energy dCi, 2005-2011)^[10] 1.9 dCi 80-101 (F9Q, vans and commercial vehicles, 1999-2007)^[8][9]
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

1.7 CDTI

See the 7 models with the 1.7 CDTI

1.9 dCi

See the 13 models with the 1.9 dCi

Other comparisons

With the 1.7 CDTI

With the 1.9 dCi

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Sources

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

Circle L engineWikipedia (inglés) · Other source · consulted 27 September 2026
Essai complet Opel Astra (H) : fiabilité et avisFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Essai complet Opel Zafira 2 : fiabilité et avisFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Essai complet Opel Meriva : fiabilité et avisFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Opel Astra H (A04): Probleme & KaufberatungGebrauchtwagenberater.de · Other source · consulted 27 September 2026 · in German
Opel Meriva A: ProblemeGebrauchtwagenberater.de · Other source · consulted 27 September 2026 · in German
Opel Meriva B: ProblemeGebrauchtwagenberater.de · Other source · consulted 27 September 2026 · in German
Renault Mégane II (2002 – 2009): Probleme & SchwachstellenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
Renault Scénic II (2003 – 2009) – Typische Probleme & KrankheitenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
Achat d'occasion : faut-il éviter le moteur 1.9 dCi F9Q chez Renault ?Planète Renault · Motoring press · published 24 January 2024 · consulted 27 September 2026 · in French
Diesels : volant moteur défectueuxFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Vanne EGR : problèmes et pannesFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Opel Corsa DWikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Opel MerivaWikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Renault F-Type engineWikipedia · Other source · consulted 27 September 2026
Moteur F RenaultWikipédia · Other source · consulted 27 September 2026 · in French
Renault Espace IVWikipedia · Other source · consulted 27 September 2026 · in German