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1.5 dCi vs 2.3 dCi (M9T): which engine is more reliable?

According to our risk index, the 2.3 dCi (M9T) carries less risk than the 1.5 dCi: 32/100 (moderate risk) versus 63/100 (high risk). The 1.5 dCi has 4 documented serious faults, the main one being «Wear and seizure of the big-end bearings»; the 2.3 dCi (M9T) has 2 documented serious faults, the main one being «Clogged or broken EGR valve damaging the turbo».

Risk index

1.5 dCi

63

High risk · 4 serious faults

Risk index

2.3 dCi (M9T)

32

Moderate risk · 2 serious faults

Lower risk

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

24 sourcesHow we work

Is the 1.5 dCi reliable?

The post-2010 1.5 dCi engines, especially the 90 hp, have a good record. The Euro 3 and Euro 4 units (2001-2010) carry serious faults: big-end bearings that can wreck the engine, a Delphi pump that fills the injection system with metal filings and, in some 105/110 hp versions, a timing belt and dual-mass flywheel that fail early.[1][2][3][4]

See the 8 of the 1.5 dCi faults

Is the 2.3 dCi (M9T) reliable?

The 2.3 dCi M9T is a van diesel with good durability if maintenance is kept up. The weak points cited are the EGR and the turbo, the injectors, and the particulate filter in urban use; the sources are mostly opinion websites.[5][6]

See the 5 of the 2.3 dCi (M9T) faults

Side-by-side comparison

Comparison of 1.5 dCi and 2.3 dCi (M9T)
1.5 dCi2.3 dCi (M9T)
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement1,461 cm³2,300 cm³
TimingTiming belt (dry)Chain
Power55–116 hp100–180 hp
Productionsince 2001[1][7][8][9][10][11][12]since 2010[5][6][13]
Reliability
Risk index (what is it?)63High risk32Moderate risk
Documented faults85
Of high or critical severity42
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: Wear and seizure of the big-end bearings
  2. Critical severity: Premature timing belt failure
  3. High severity: Delphi high-pressure pump that sheds filings and damages the injection
  1. High severity: Clogged or broken EGR valve damaging the turbo
  2. Medium severity: Faulty injectors on the 2.3 dCi
  3. Medium severity: Diesel particulate filter (DPF) clogged in urban use
Most expensive documented repairup to €2,000Premature dual-mass flywheel failure and clutch problemsPublished figure[14][15]up to €2,300Clogged or broken EGR valve damaging the turboPublished figure[5][16]
Which versions to buy
BuyRecommended versions
  • 1.5 dCi Energy Euro 6 with NOx trap (90 and 110 hp, 2015-2018)[17][18][19]
  • 1.5 dCi in Mercedes-Benz and Infiniti (OM 607 / OM 608, 2012-2020)[12][20]
  • 2.3 dCi 100-125 hp (M9T)[6]
  • 2.3 dCi 130-145 hp (M9T)[6]
With cautionVersions to be cautious about
  • 1.5 dCi Euro 4 (68/70, 85/86 and 105/106 hp, 2005-2010)[1][2][3][9]
  • 1.5 dCi Euro 5 with particulate filter (75, 90, 95 and 110 hp, 2010-2015)[1][3][21]
  • 1.5 Blue dCi with SCR and AdBlue (85, 95, 100 and 115 hp, from 2018)[18][22][23]
  • 2.3 dCi 150-180 hp (M9T, some twin-turbo)[6]
  • 2.3 dCi in the Navara D23 (NP300)[24]
AvoidVersions to avoid
  • 1.5 dCi Euro 3 (65, 80/82 and 100 hp, 2001-2005)[1][4]
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

1.5 dCi

See the 46 models with the 1.5 dCi

2.3 dCi (M9T)

Other comparisons

With the 1.5 dCi

With the 2.3 dCi (M9T)

Compare other engines

That is the comparison you are viewing: change one of the two engines.

Sources

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

  1. Fiabilité du 1.5 dCiFiches-auto.fr · Motoring press · published 19 April 2024 · consulted 26 September 2026 · in French
  2. Fiabilité Renault Clio 3 : que vaut le modèle en occasion ?Caradisiac · Motoring press · published 26 November 2012 · consulted 26 September 2026 · in French
  3. Maxi-fiche fiabilité : que vaut le Renault Scénic 3 en occasion ?Caradisiac · Motoring press · published 2 February 2016 · consulted 26 September 2026 · in French
  4. Maxi-fiche occasion : que vaut le Renault Scénic 2 en seconde main ?Caradisiac · Motoring press · published 29 October 2014 · consulted 26 September 2026 · in French
  5. Renault Master III 2.3 dCi 130: fiabilité, pannes et coûtsCarverif · Other source · consulted 5 October 2026 · in French
  6. Fiabilité Renault Master 2.3 dCiCarverif · Other source · consulted 5 October 2026 · in French
  7. Renault K-Type engineWikipedia · Other source · consulted 26 September 2026
  8. Moteur K RenaultWikipédia · Other source · consulted 26 September 2026 · in French
  9. Fiabilité Renault Mégane 3 : que vaut le modèle en occasion ?Caradisiac · Motoring press · published 25 November 2015 · consulted 26 September 2026 · in French
  10. Mercedes abandonne le 1.5 dCi Renault pour un moteur maison, qui émet plus de CO2 !Caradisiac · Motoring press · published 26 October 2020 · consulted 26 September 2026 · in French
  11. Nissan : le Qashqai reçoit un nouveau moteur dCiCaradisiac · Motoring press · published 14 September 2018 · consulted 26 September 2026 · in French
  12. Estos son los motores Renault que usa MercedesDiariomotor · Motoring press · published 22 December 2019 · consulted 26 September 2026 · in Spanish
  13. Renault Master (tercera generación)Wikipedia · Other source · consulted 5 October 2026
  14. Volante bimasa, averías y precio de sustituciónDiariomotor · Motoring press · published 3 November 2020 · consulted 26 September 2026 · in Spanish
  15. Diesels : volant moteur défectueuxFiches-auto.fr · Owners' forum · published 17 October 2025 · consulted 26 September 2026 · in French
  16. Fiabilité du Renault Master RT 2.3 dCi: analyse complèteCarverif · Other source · consulted 5 October 2026 · in French
  17. Fiabilité du Renault Kadjar : la maxi-fiche occasion de CaradisiacCaradisiac · Motoring press · published 19 November 2020 · consulted 26 September 2026 · in French
  18. Fiabilité du Dacia Duster 2 : la maxi-fiche occasion de CaradisiacCaradisiac · Motoring press · published 27 April 2022 · consulted 26 September 2026 · in French
  19. Fiabilité du Renault Captur : la maxi-fiche occasion de CaradisiacCaradisiac · Motoring press · published 2 March 2018 · consulted 26 September 2026 · in French
  20. Fiabilité des 180d / 180 CDI MercedesFiches-auto.fr · Motoring press · consulted 26 September 2026 · in French
  21. Fiabilité du Nissan Qashqai 2 : la maxi-fiche occasion de CaradisiacCaradisiac · Motoring press · published 22 December 2017 · consulted 26 September 2026 · in French
  22. Fiabilité du 1.5 Blue dCiFiches-auto.fr · Motoring press · published 18 May 2022 · consulted 26 September 2026 · in French
  23. Maxi-fiche fiabilité - Renault Clio 5 : loin d'être irréprochableCaradisiac · Motoring press · published 19 April 2024 · consulted 26 September 2026 · in French
  24. Nissan Navara wymaga zmian systemu oczyszczania spalinAutokatalog.pl · Motoring press · published 23 August 2023 · consulted 5 October 2026 · in another language