1.7 CDTI vs 2.5 TDI R5: which engine is more reliable?

According to our risk index, the 1.7 CDTI carries less risk than the 2.5 TDI R5: 36/100 versus 45/100 (both moderate risk). The 1.7 CDTI has 3 documented serious faults, the main one being «Dual-mass flywheel and clutch wear»; the 2.5 TDI R5 has 2 documented serious faults, the main one being «Plasma coating flaking off the cylinders».

Risk index

1.7 CDTI

Moderate risk · 3 serious faults

Lower risk

Risk index

2.5 TDI R5

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 5 October 202615 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 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.^[8][9][10]

See the 5 of the 2.5 TDI R5 faults

Side-by-side comparison

Comparison of 1.7 CDTI and 2.5 TDI R5
Item	1.7 CDTI	2.5 TDI R5
Technical data
Type	Engine	Engine
Fuel	Diesel	Diesel
Displacement	1,686 cm³	2,461 cm³
Timing	Timing belt (dry)	Timing belt (dry)
Power	100–130 hp	88–174 hp
Production	2003–2015^[1][11][12]	2003–2011^[13][14][15]
Reliability
Risk index (what is it?)	36Moderate risk	45Moderate risk
Documented faults	5	5
Of high or critical severity	3	2
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: Plasma coating flaking off the cylinders High severity: Camshaft and hydraulic tappet wear Medium severity: Leaks and play in the unit 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]	2.5 TDI 130 and 174 hp with DPF (BNZ, BPC, 2006-2009)^[8] 2.5 TDI common rail Crafter (88 to 163 hp, 2006-2011)^[15]
AvoidVersions to avoid	None	2.5 TDI 130 and 174 hp (AXD, AXE, 2003-2006)^[8]

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

2.5 TDI R5

Other comparisons

With the 1.7 CDTI

With the 2.5 TDI R5

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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
VW T5 4Motion Gebrauchtwagen-TestAuto Bild · Motoring press · consulted 5 October 2026 · in German
Kaufberatung gebrauchter VW T5 (2003-2015)Promobil · Motoring press · consulted 5 October 2026 · in German
Ratgeber Technik: Fehler VW T5Auto Bild · Motoring press · consulted 5 October 2026 · in German
Opel Corsa DWikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Opel MerivaWikipedia (alemán) · Other source · consulted 27 September 2026 · in German
VW T5Wikipedia (de) · Other source · consulted 5 October 2026 · in German
VW Touareg IWikipedia (de) · Other source · consulted 5 October 2026 · in German
Volkswagen CrafterWikipedia (es) · Other source · consulted 5 October 2026 · in Spanish