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MotorFiable

2.3 dCi (M9T) vs 2.5 TDI R5: which engine is more reliable?

According to our risk index, the 2.3 dCi (M9T) carries less risk than the 2.5 TDI R5: 32/100 versus 45/100 (both moderate risk). The 2.3 dCi (M9T) has 2 documented serious faults, the main one being «Clogged or broken EGR valve damaging the turbo»; the 2.5 TDI R5 has 2 documented serious faults, the main one being «Plasma coating flaking off the cylinders».

Risk index

2.3 dCi (M9T)

32

Moderate risk · 2 serious faults

Lower risk

Risk index

2.5 TDI R5

45

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

14 sourcesHow we work

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.[1][2]

See the 5 of the 2.3 dCi (M9T) faults

Is the 2.5 TDI R5 reliable?

The 2.5 TDI R5 in the T5 and the Touareg has a poor reputation: camshaft wear, pump injectors and cylinder coating. The later series were more reliable. It is not Audi's V6 TDI.[3][4][5]

See the 5 of the 2.5 TDI R5 faults

Side-by-side comparison

Comparison of 2.3 dCi (M9T) and 2.5 TDI R5
2.3 dCi (M9T)2.5 TDI R5
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement2,300 cm³2,461 cm³
TimingChainTiming belt (dry)
Power100–180 hp88–174 hp
Productionsince 2010[1][2][6]2003–2011[7][8][9]
Reliability
Risk index (what is it?)32Moderate risk45Moderate risk
Documented faults55
Of high or critical severity22
Worst severityHigh severityCritical severity
Main faults
  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
  1. Critical severity: Plasma coating flaking off the cylinders
  2. High severity: Camshaft and hydraulic tappet wear
  3. Medium severity: Leaks and play in the unit injectors
Most expensive documented repairup to €2,300Clogged or broken EGR valve damaging the turboPublished figure[1][10]No reliable data
Which versions to buy
BuyRecommended versions
  • 2.3 dCi 100-125 hp (M9T)[2]
  • 2.3 dCi 130-145 hp (M9T)[2]
None
With cautionVersions to be cautious about
  • 2.3 dCi 150-180 hp (M9T, some twin-turbo)[2]
  • 2.3 dCi in the Navara D23 (NP300)[11]
  • 2.3 OM 699 in the Mercedes X-Class, 163 and 190 hp (2017-2020)[2][12]
  • 2.5 TDI 130 and 174 hp with DPF (BNZ, BPC, 2006-2009)[3]
  • 2.5 TDI common rail Crafter (88 to 163 hp, 2006-2011)[9]
  • 2.5 TDI of the Transporter T4 (88, 102 and 151 hp, 1995-2003)[13][14]
  • 2.5 TDI 140 hp from Volvo (D5252T, 1996-2000)[13][14]
AvoidVersions to avoidNone
  • 2.5 TDI 130 and 174 hp (AXD, AXE, 2003-2006)[3]

Severity of each fault: green, low; amber, medium; red, high; dark red, critical. How we rate them

Cars that each one is fitted to

2.3 dCi (M9T)

2.5 TDI R5

Other comparisons

With the 2.3 dCi (M9T)

With the 2.5 TDI R5

Compare other engines

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Sources

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

  1. Renault Master III 2.3 dCi 130: fiabilité, pannes et coûtsCarverif · Other source · consulted 5 October 2026 · in French
  2. Fiabilité Renault Master 2.3 dCiCarverif · Other source · consulted 5 October 2026 · in French
  3. VW T5 4Motion Gebrauchtwagen-TestAuto Bild · Motoring press · consulted 5 October 2026 · in German
  4. Kaufberatung gebrauchter VW T5 (2003-2015)Promobil · Motoring press · consulted 5 October 2026 · in German
  5. Ratgeber Technik: Fehler VW T5Auto Bild · Motoring press · consulted 5 October 2026 · in German
  6. Renault Master (tercera generación)Wikipedia · Other source · consulted 5 October 2026
  7. VW T5Wikipedia (de) · Other source · consulted 5 October 2026 · in German
  8. VW Touareg IWikipedia (de) · Other source · consulted 5 October 2026 · in German
  9. Volkswagen CrafterWikipedia (es) · Other source · consulted 5 October 2026 · in Spanish
  10. Fiabilité du Renault Master RT 2.3 dCi: analyse complèteCarverif · Other source · consulted 5 October 2026 · in French
  11. Nissan Navara wymaga zmian systemu oczyszczania spalinAutokatalog.pl · Motoring press · published 23 August 2023 · consulted 5 October 2026 · in another language
  12. Mercedes-Benz X-Klasse: motores OM 699 y OM 642, producción en BarcelonaWikipedia (de) · Other source · consulted 2 November 2026 · in German
  13. VW T4 im Gebraucht-Check: Darauf muss man achtenPromobil · Motoring press · consulted 2 November 2026 · in German
  14. VW T4 Buying Guide: Problem AreasHeritage Parts Centre · Other source · consulted 2 November 2026