Are you considering buying a used diesel car? Although it no longer smells like holiness in cities (Crit’Air, ZFE, etc.), diesel still remains attractive and affordable on the second-hand market. In 2023, of the 5.2 million used cars sold in France, 2.71 million were diesels. This is very symbolic: this represents 51.7% of second-hand salesand at the same time in a new market, it has fallen to less than 10% of registrations. If you, like most French people, are also planning to take the plunge, take your time. Some models may be attractive for the price, but hide serious reliability issues. If in doubt, here are the diesel units to avoid to avoid unpleasant surprises…

In Renault/Nissan/Dacia:

• 5 dCi 60/65/70/75/80/85/90/100/105/110 hp.: Mainly it was the injection pumps (they fell apart and caused the engine to fail) that caused the problem for this engine family. In versions with a power of 60, 80 and 90 hp. before 2006 the crankshaft is brittle as well. Nissan Qashqai was a victim of broken connecting rods on 1.5 dCi 106 hp. and on some 2.0 150 hp, before 2008, and engine failure before 2010 (pulleys and timing belt).
• 0 dCi: examples that rolled off the assembly line during the first year of production (Laguna III only) had problems with the injector, which became more reliable in 2009.

In Peugeot/Citroën:

Sold since 2014, units meeting Euro 6 standards and renamed BlueHDi, so far without reproaches (1.6 75, 10 0 and 200 hp and 2.0 15 0 and 18 0 hp). However, some, still young, should prove themselves with time.

• 4 HDI 70 hp: turbine failures and problems with injectors characterized the first years of this unit’s life. It was made reliable in 2011.
• 6 HDi 90/92 hp: turbocharging malfunctions of the first copies were checked in 2014.
• 6 HDI 110/112/115 hp: Persistent turbo, flywheel and clutch problems experienced up to 2011 were resolved with the release of the new version that year.
• 0 HDI 136/138 hp: If in 2009 the epidemic affecting turbochargers weakened, it was only three years later that it was truly eradicated, including under the hood of Ford and Volvo, which use the same unit.
• 2 HDI 170/173 hp: Inconveniences related to turbocharging (solenoid valve, connecting rod, etc.) have been eliminated on engines produced since 2008.
• V6 2.7 HDI 204 hp: This engine, which was also used by Land Rover and Jaguar, had problems with the EGR valve and alternatorsettled in 2008.

Read also:

EGR valve: presentation and operation

Turbo: our tips for saving it

How does a particulate filter work?