1.3 Multijet vs OM651: which engine is more reliable?

According to our risk index, the 1.3 Multijet carries less risk than the OM651: 64/100 (high risk) versus 89/100 (very high risk). The 1.3 Multijet has 4 documented serious faults, the main one being «Timing chain stretch and tensioner failure»; the OM651 has 4 documented serious faults, the main one being «Timing chain stretch and tensioner failure».

Risk index

1.3 Multijet

High risk · 4 serious faults

Lower risk

Risk index

OM651

Very high risk · 4 serious faults

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

Reviewed on 26 September 202616 sources How 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 OM651 reliable?

The OM651 is the four-cylinder diesel Mercedes-Benz used most between 2008 and 2019, in 1.8 and 2.2-litre versions with 95 to 204 hp. It is generally a solid engine, but the early units (above all the 220 and 250 CDI from 2008 to 2011) had Delphi piezo injectors that were prone to failure and a timing chain that can stretch prematurely; both problems were only partly corrected over the years.^[5][6][7][8]

See the 6 of the OM651 faults

Side-by-side comparison

Comparison of 1.3 Multijet and OM651
Item	1.3 Multijet	OM651
Technical data
Type	Engine	Engine
Fuel	Diesel	Diesel
Displacement	1,248 cm³	2,143 cm³
Timing	Chain	Chain
Power	69–105 hp	95–204 hp
Production	2003–2024^[9][10][11]	2008–2019^{[5][7][12][13][14]}
Reliability
Risk index (what is it?)	64High risk	89Very high risk
Documented faults	5	6
Of high or critical severity	4	4
Worst severity	Critical severity	Critical severity
Main faults	Critical severity: Timing chain stretch and tensioner failure High severity: Incomplete particulate filter regenerations and oil dilution High severity: Seized variable-geometry turbo	Critical severity: Timing chain stretch and tensioner failure High severity: Delphi piezo injector failure (220/250 CDI) High severity: EGR and particulate filter clogging, and emissions software updates
Most expensive documented repair	up to €1,200Injector and high-pressure pump wear from contaminated fuelPublished figure^[3]	up to €5,900Delphi piezo injector failure (220/250 CDI)Published figure^[7]
Which versions to buy
BuyRecommended versions	None	None
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]	OM651 1.8 CDI 109-136 hp (180/200 CDI)^[6][15] OM651 2.2 CDI 120-190 hp (200/220 CDI, 114-119 CDI)^[6][7][16] OM651 2.2 CDI twin-turbo 204 hp (250 CDI / 250d / 250 BlueTEC)^[6]
AvoidVersions to avoid	None	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

1.3 Multijet

See the 20 models with the 1.3 Multijet

OM651

See the 15 models with the OM651

Other comparisons

With the 1.3 Multijet

With the OM651

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Sources

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

Fiat 1.3 Multijet: ficha técnica, problemas y tuningMotordinámico · Other source · consulted 26 September 2026 · in Spanish
1.3 CDTi Opel (Z13DT) Multijet: ficha técnica, problemas y tuningMotordinámico · Other source · consulted 26 September 2026 · in Spanish
Fiat 1.3 Multijet: problemas, fallos y averías más frecuentesTotalrenting · Other source · consulted 26 September 2026 · in Spanish
Fiat 1.3 JTD/Multijet: corrente folgada e entupimento dos canais de lubrificaçãoProvmec · Technical documentation · consulted 26 September 2026 · in Portuguese
Mercedes-Benz OM651 engineWikipedia · Other source · consulted 26 September 2026
Mercedes OM651: Typische Probleme und HaltbarkeitGebrauchtwagenberater · Motoring press · consulted 26 September 2026 · in German
Mercedes OM651 : injecteurs, chaîne, fiabilitéAutoCopilot · Motoring press · published 2026 · consulted 26 September 2026 · in French
Rückruf November 2009 - Mercedes-Benz C-Klasse, jeweils als 220 CDI oder 250 CDI (mit Dieselmotor OM 651)Autoservicepraxis · Motoring press · published November 2009 · consulted 26 September 2026 · in German
Fiat JTD engineWikipedia · Other source · consulted 26 September 2026
Moteur Fiat 1.3 MultiJetWikipédia · Other source · consulted 26 September 2026 · in French
Motor Fiat 1.3 JTD 16v: más información sobre el motorkm77 · Technical documentation · published September 2002 · consulted 26 September 2026 · in Spanish
Mercedes-Benz OM651 EngineSportlich-Leicht · Other source · consulted 26 September 2026
Mercedes OM651 turbodiésel: ficha técnica, problemas y tuningMotordinámico · Motoring press · consulted 26 September 2026 · in Spanish
Mercedes W447: Vito & V-Klasse – Motoren und ProblemeKFZ Dietrich · Motoring press · consulted 26 September 2026 · in German
Mercedes-Benz Clase A (2012): información técnicakm77 · Technical documentation · consulted 26 September 2026 · in Spanish
Mercedes-Rückruf: Wieder Probleme mit dem OM651-DieselmotorAutoservicepraxis · Motoring press · published 12 January 2015 · consulted 26 September 2026 · in German