Engines to avoid when buying used: the fragile units and the most reliable ones

Which engines should you avoid when buying used? According to our 25 engine pages, six stand out: the 1.6 THP, the 1.0 EcoBoost, the 1.5 dCi, the Toyota 1.8 hybrid, the 1.2 TCe and the 1.2 PureTech. They score 3/5 or less, or have a severity-3 fault that is not just a recall. Conversely, recent VW, Renault and Toyota engines are the best rated.

How did we choose these engines?

We read the pages of our engines: verdict, reliability score out of 5, sourced faults with their severity, years to avoid or to favour. No engine has the "avoid" verdict: the six below all have the "with precautions" verdict. We kept those scoring 3/5 or less, or with a severity-3 fault that is not a recall. The scale is detailed in our methodology. The models listed are those with at least one version that uses the engine in our guides; figures are those on the pages as of 29 October 2026.

Which used engines should you avoid?

1.6 THP / PureTech 180-225 (PSA-BMW): 2.5/5

Turbo petrol with a timing chain, launched in 2006. Years to avoid according to the page: 2006 to 2010. No severity-3 fault, but four severity-2 faults: "Allongement de la chaîne de distribution (tendeur défaillant)" (timing chain stretch, faulty tensioner), "Pompe à carburant haute pression défaillante (1.6 THP)" (failing high-pressure fuel pump), "Consommation d'huile excessive" (excessive oil consumption), "Fuites du circuit de refroidissement (boîtier thermostat, pompe à eau)" (cooling system leaks), plus two severity-1 faults, including "Boîtier papillon motorisé défaillant (1.6 PureTech 180 et 225)" (failing motorised throttle body; engines built up to September 2019). Models: Peugeot 208 I, Peugeot 3008 II, Peugeot 508 II, Citroën C5 Aircross I, DS 7.

1.0 EcoBoost (Ford): 3/5

Turbo three-cylinder, since 2012. Years to avoid: 2012 and 2013. Two severity-3 faults: "Courroie humide qui se dégrade et bouche la crépine d'huile (1.0 EcoBoost)" (wet belt that degrades and clogs the oil strainer) and "Durite de refroidissement qui lâche et surchauffe (1.0 EcoBoost 2011-2013)" (coolant hose that fails and causes overheating). The page specifies that Ford switched to a chain on some engines, but that a submerged belt still drives the oil pump; it recommends checking by serial number. Models: Ford Fiesta VII, Ford Focus IV, Ford EcoSport, Ford B-Max, Ford Mondeo IV.

1.5 dCi / Blue dCi K9K (Renault-Nissan): 3/5

Diesel, since 2001. Years to avoid: 2001 to 2005. Severity-3 fault: "Usure des coussinets de bielle (premières versions)" (connecting rod bearing wear, early versions), of limited scale according to the page, which advises shorter oil change intervals. Add "Pompe d'injection Delphi produisant de la limaille" (Delphi injection pump producing metal shavings; severity 2) and two severity-1 faults. Models: Renault Clio IV, Renault Mégane III, Dacia Duster II, Nissan Qashqai II.

Toyota 1.8 hybrid (2ZR-FXE): 3/5

Hybrid, since 2009, with no year to avoid. Severity-3 fault: "Batterie de traction en fin de vie" (traction battery at end of life), which affects older Prius cars, with an expensive replacement according to the page. Two severity-2 faults: "Défaillance du joint de culasse (Prius 3 et Prius+)" (cylinder head gasket failure), reported from 200,000 km, and "Pompe à eau électrique défaillante" (failing electric water pump). Models: Toyota Prius III, Toyota Prius+, Toyota C-HR I, Toyota Auris II.

1.2 TCe / DIG-T (H5Ft): 3.5/5

Turbo petrol, built from 2012 to 2018. Years to avoid: 2013 to 2015. Severity-3 fault: "Surconsommation d'huile pouvant mener à la casse moteur" (excessive oil consumption that can lead to engine failure), which mainly affects engines built from late 2012 to mid-2016; the page adds that Renault organised no recall. Severity 2: "Chaîne de distribution bruyante ou qui se détend" (noisy or slackening timing chain). Models: Dacia Duster I, Renault Captur I, Renault Clio IV, Nissan Qashqai II, Renault Mégane III.

1.2 PureTech (EB2, Stellantis): 3.5/5

Petrol, since 2012. Severity-3 fault: "Dégradation de la courroie de distribution « humide » (1.2 PureTech)" (degradation of the "wet" timing belt); severity 2: "Surconsommation d'huile (1.2 PureTech)" (excessive oil consumption). According to the page, recent engines are less exposed (belt revised in June 2022, oil consumption corrected in 2023) and the years 2023 to 2025 are to be favoured. Models: Peugeot 208 II, Citroën C3 III, Opel Corsa F, Peugeot 2008 II, Opel Mokka II. Our article details what to check on a PureTech.