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1.3 Multijet vs 2.2 CDI (OM646): which engine is more reliable?

According to our risk index, the 2.2 CDI (OM646) carries less risk than the 1.3 Multijet: 46/100 (moderate risk) versus 64/100 (high risk). The 1.3 Multijet has 4 documented serious faults, the main one being «Timing chain stretch and tensioner failure»; the 2.2 CDI (OM646) has 1 documented serious fault, the main one being «Injector seal leak with carbonisation around the seat».

Risk index

1.3 Multijet

64

High risk · 4 serious faults

Risk index

2.2 CDI (OM646)

46

Moderate risk · 1 serious fault

Lower risk

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 1.3 Multijet reliable?

The 1.3 Multijet is a reliable diesel in the basics, but it has a known weak point across all its brands: the timing chain and its tensioner can stretch or fail if oil changes are neglected, with a risk of serious damage. In urban use, the EGR valve, the particulate filter and the variable-geometry turbo add to the list.[1][2][3][4]

See the 5 of the 1.3 Multijet faults

Is the 2.2 CDI (OM646) reliable?

The OM646 is the 2.2 CDI four-cylinder diesel that Mercedes-Benz fitted between 2002 and 2010 to the C-Class, E-Class, Vito/Viano and Sprinter, as the successor to the OM611 (1998-2006). It is a fundamentally sound engine, considered robust in its mechanical base, but with known and well-documented faults: leaks at the injector seals, a clogged EGR valve, particulate filter sensor failures and a short-lived water pump on some versions.[5][6][7][8]

See the 6 of the 2.2 CDI (OM646) faults

Side-by-side comparison

Comparison of 1.3 Multijet and 2.2 CDI (OM646)
1.3 Multijet2.2 CDI (OM646)
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement1,248 cm³2,148 cm³
TimingChainChain
Power69–105 hp82–170 hp
Production2003–2024[9][10][11]1998–2010[5][12][13]
Reliability
Risk index (what is it?)64High risk46Moderate risk
Documented faults56
Of high or critical severity41
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: Timing chain stretch and tensioner failure
  2. High severity: Incomplete particulate filter regenerations and oil dilution
  3. High severity: Seized variable-geometry turbo
  1. High severity: Injector seal leak with carbonisation around the seat
  2. Medium severity: EGR valve clogged or seized by soot
  3. Medium severity: Leak and premature failure of the water pump
Most expensive documented repairup to €1,200Injector and high-pressure pump wear from contaminated fuelPublished figure[3]up to €300Faulty air flow meter on the 220 CDI (OM 611 and OM 646)Published figure[14]
Which versions to buy
BuyRecommended versionsNoneNone
With cautionVersions to be cautious about
  • 1.3 Multijet 8v (69-105 hp, 2003-2009)[1][2][3]
  • 1.3 Multijet II 16v Euro 5 (75-95 hp, 2009-2015)[2][4]
  • 1.3 Multijet II 16v Euro 6 (95 hp, 2015-2020)[2][4]
  • OM611 (predecessor, 2.2 CDI, 1998-2006)[6][8]
  • OM646 pre-EVO (2002-2007, Euro 3/4, 88-150 hp)[6][7][8]
  • OM646 EVO (2006-2009, up to 170 hp)[8]
AvoidVersions to avoidNoneNone

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

Cars that each one is fitted to

1.3 Multijet

See the 20 models with the 1.3 Multijet

2.2 CDI (OM646)

Other comparisons

With the 1.3 Multijet

With the 2.2 CDI (OM646)

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. Fiat 1.3 Multijet: ficha técnica, problemas y tuningMotordinámico · Other source · consulted 26 September 2026 · in Spanish
  2. 1.3 CDTi Opel (Z13DT) Multijet: ficha técnica, problemas y tuningMotordinámico · Other source · consulted 26 September 2026 · in Spanish
  3. Fiat 1.3 Multijet: problemas, fallos y averías más frecuentesTotalrenting · Other source · consulted 26 September 2026 · in Spanish
  4. Fiat 1.3 JTD/Multijet: corrente folgada e entupimento dos canais de lubrificaçãoProvmec · Technical documentation · consulted 26 September 2026 · in Portuguese
  5. Mercedes-Benz OM 646/OM 647/OM 648Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  6. Mercedes C-Klasse W203 – Typische Probleme & SchwachstellenGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  7. Fiabilité 200 CDI MercedesFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  8. Fiabilité 220 CDIFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  9. Fiat JTD engineWikipedia · Other source · consulted 26 September 2026
  10. Moteur Fiat 1.3 MultiJetWikipédia · Other source · consulted 26 September 2026 · in French
  11. Motor Fiat 1.3 JTD 16v: más información sobre el motorkm77 · Technical documentation · published September 2002 · consulted 26 September 2026 · in Spanish
  12. Mercedes-Benz OM646 engineWikipedia · Other source · consulted 27 September 2026
  13. Mercedes-Benz OM611 engineWikipedia · Other source · consulted 27 September 2026
  14. Caudalímetro o sensor MAF: qué es, cómo funciona y cuáles son las averías más frecuentesDiariomotor · Motoring press · consulted 30 October 2026 · in Spanish