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1.3 Multijet vs OM656: which engine is more reliable?

According to our risk index, the OM656 carries less risk than the 1.3 Multijet: 39/100 (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 OM656 has 2 documented serious faults, the main one being «Leak in the vacuum-driven coolant pump (fire risk)».

Risk index

1.3 Multijet

64

High risk · 4 serious faults

Risk index

OM656

39

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

16 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 OM656 reliable?

The OM656 is the roughly 3.0-litre in-line six-cylinder diesel with which Mercedes-Benz replaced the OM642 V6 from 2017 in the S-Class, E-Class, CLS, GLE, GLS and G-Class (350 d, 400 d and 450 d). It has few documented faults: the known campaign is the coolant pump one of 2021-2022, and the timing chain recall that circulates belongs to the OM654. Guides warn about the AdBlue/SCR system, the EGR and, in isolated cases, the roller rocker arms, without figures.[5][6][7][8][9][10][11][12]

See the 4 of the OM656 faults

Side-by-side comparison

Comparison of 1.3 Multijet and OM656
1.3 MultijetOM656
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement1,248 cm³2,925 cm³
TimingChainChain
Power69–105 hp272–367 hp
Production2003–2024[13][14][15]since 2017[5][6][16]
Reliability
Risk index (what is it?)64High risk39Moderate risk
Documented faults54
Of high or critical severity42
Worst severityCritical severityCritical 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. Critical severity: Leak in the vacuum-driven coolant pump (fire risk)
  2. Medium severity: NOx sensor failure and AdBlue (SCR) system warnings
  3. Medium severity: EGR valve clogged with soot after short journeys
Most expensive documented repairup to €1,200Injector and high-pressure pump wear from contaminated fuelPublished figure[3]No reliable data
Which versions to buy
BuyRecommended versionsNone
  • OM656 3.0 diesel with electric assistance (D 30, from 2023)[8][9][11]
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]
  • OM656 2.9 diesel 350 d (OM 656 D 29 R SCR, from 2017)[7][8][9]
  • OM656 2.9 diesel 400 d (OM 656 D 29 SCR, from 2017)[7][8][9][11]
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

OM656

See the 11 models with the OM656

Other comparisons

With the 1.3 Multijet

With the OM656

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 OM656 engineWikipedia · Other source · consulted 9 October 2026
  6. Mercedes-Benz OM 656Wikipedia (alemán) · Other source · consulted 9 October 2026 · in German
  7. Rückruf für OM 656 und OM 654 Motoren wegen KühlmittelpumpeMBpassion · Motoring press · published 9 December 2021 · consulted 9 October 2026 · in German
  8. Mercedes-Rückruf: Kühlmittelprobleme bei DieselautosAUTOHAUS · Motoring press · published 5 January 2022 · consulted 9 October 2026 · in German
  9. DVSA – base de llamadas a revisiónDVSA (Reino Unido) · Other source · consulted 9 October 2026
  10. Mercedes-Benz GLC (X253): Alle typischen Probleme & MängelGebrauchtwagenberater · Motoring press · consulted 9 October 2026 · in German
  11. Mercedes OM656 Diesel: Häufige Probleme, Ursachen & Tipps zur Vermeidung von MotorschädenMBpassion · Motoring press · published 19 February 2026 · consulted 9 October 2026 · in German
  12. Mercedes-Benz OM656 Engine Guide: Reliability, Common Problems & Tuning PotentialEuro Premium Parts · Technical documentation · consulted 9 October 2026
  13. Fiat JTD engineWikipedia · Other source · consulted 26 September 2026
  14. Moteur Fiat 1.3 MultiJetWikipédia · Other source · consulted 26 September 2026 · in French
  15. Motor Fiat 1.3 JTD 16v: más información sobre el motorkm77 · Technical documentation · published September 2002 · consulted 26 September 2026 · in Spanish
  16. Mercedes-Benz S-Class (W222)Wikipedia · Other source · consulted 9 October 2026