2.2 TD4 / SD4 vs OM656: which engine is more reliable?

According to our risk index, the 2.2 TD4 / SD4 carries less risk than the OM656: 32/100 versus 39/100 (both moderate risk). The 2.2 TD4 / SD4 has 2 documented serious faults, the main one being «Coolant leak from the EGR valve cooler»; the OM656 has 2 documented serious faults, the main one being «Leak in the vacuum-driven coolant pump (fire risk)».

Risk index

2.2 TD4 / SD4

Moderate risk · 2 serious faults

Lower risk

Risk index

OM656

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 9 October 202616 sources How we work

Is the 2.2 TD4 / SD4 reliable?

This is the 2.2-litre diesel of the Freelander 2, the first Evoque, the 2014-2015 Discovery Sport and the Jaguar XF 2.2D. The sources consulted do not describe it as a problematic engine, but they point to three things: the EGR cooler, the DPF in urban use, and replacing the belt along with the water pump.^[1][2][3]

See the 3 of the 2.2 TD4 / SD4 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.^{[4][5][6][7][8][9][10][11]}

See the 4 of the OM656 faults

Side-by-side comparison

Comparison of 2.2 TD4 / SD4 and OM656
Item	2.2 TD4 / SD4	OM656
Technical data
Type	Engine	Engine
Fuel	Diesel	Diesel
Displacement	2,179 cm³	2,925 cm³
Timing	Timing belt (dry)	Chain
Power	150–200 hp	272–367 hp
Production	2006–2015^{[12][13][14][15]}	since 2017^[4][5][16]
Reliability
Risk index (what is it?)	32Moderate risk	39Moderate risk
Documented faults	3	4
Of high or critical severity	2	2
Worst severity	Critical severity	Critical severity
Main faults	High severity: Coolant leak from the EGR valve cooler Critical severity: Timing belt failure and water pump failure Medium severity: Diesel particulate filter (DPF) clogged by urban use	Critical severity: Leak in the vacuum-driven coolant pump (fire risk) Medium severity: NOx sensor failure and AdBlue (SCR) system warnings Medium severity: EGR valve clogged with soot after short journeys
Most expensive documented repair	No reliable data	No reliable data
Which versions to buy
BuyRecommended versions	None	OM656 3.0 diesel with electric assistance (D 30, from 2023)^[7][8][10]
With cautionVersions to be cautious about	2.2 TD4 / eD4 150-160 hp^[1][3][15] 2.2 SD4 190-200 hp^[2]	OM656 2.9 diesel 350 d (OM 656 D 29 R SCR, from 2017)^[6][7][8] OM656 2.9 diesel 400 d (OM 656 D 29 SCR, from 2017)^{[6][7][8][10]}
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

2.2 TD4 / SD4

OM656

See the 11 models with the OM656

Other comparisons

With the 2.2 TD4 / SD4

With the OM656

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Sources

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

Land Rover Freelander Mk2 common problems 2006-2015Haynes · Technical documentation · published December 2022 · consulted 5 October 2026
Test / Avis Land Rover Range Rover Evoque 2.2 SD4 190 ch (2011-2018)Fiches-auto · Owners' forum · consulted 5 October 2026 · in French
Problemas Land Rover Freelander 2Totalrenting · Other source · consulted 5 October 2026 · in Spanish
Mercedes-Benz OM656 engineWikipedia · Other source · consulted 9 October 2026
Mercedes-Benz OM 656Wikipedia (alemán) · Other source · consulted 9 October 2026 · in German
Rückruf für OM 656 und OM 654 Motoren wegen KühlmittelpumpeMBpassion · Motoring press · published 9 December 2021 · consulted 9 October 2026 · in German
Mercedes-Rückruf: Kühlmittelprobleme bei DieselautosAUTOHAUS · Motoring press · published 5 January 2022 · consulted 9 October 2026 · in German
DVSA – base de llamadas a revisiónDVSA (Reino Unido) · Other source · consulted 9 October 2026
Mercedes-Benz GLC (X253): Alle typischen Probleme & MängelGebrauchtwagenberater · Motoring press · consulted 9 October 2026 · in German
Mercedes OM656 Diesel: Häufige Probleme, Ursachen & Tipps zur Vermeidung von MotorschädenMBpassion · Motoring press · published 19 February 2026 · consulted 9 October 2026 · in German
Mercedes-Benz OM656 Engine Guide: Reliability, Common Problems & Tuning PotentialEuro Premium Parts · Technical documentation · consulted 9 October 2026
Land Rover FreelanderWikipedia (inglés) · Other source · consulted 5 October 2026
Land Rover Discovery SportWikipedia (inglés) · Other source · consulted 5 October 2026
Jaguar XF (X250)Wikipedia (inglés) · Other source · consulted 5 October 2026
How to fit a timing belt on a Land Rover Freelander 2Professional Motor Mechanic (PMM) · Motoring press · published 22 January 2018 · consulted 5 October 2026
Mercedes-Benz S-Class (W222)Wikipedia · Other source · consulted 9 October 2026