1. The Consensus of the Experts: An Endemic Design Problem
Expert and mechanical opinion on the PureTech 1.2 EB2 engine is unanimous in pointing to the oil-bathed timing belt system as the main cause of its bad reputation, leading to it being derogatorily nicknamed “PudreTech”. It is argued that the engine has a design flaw that inevitably compromises its reliability, regardless of official maintenance.
Specialists claim that the engine is a “misbegotten project” and that, while the mechanics themselves are “relatively good”, the big problem lies in the wet belt and the dirt it generates. The potential risk of belt breakage or clogged ducts causing seizure, even with low mileage (some report problems with less than 40,000 km, especially on short or cold runs), is very high.
2. The Technical Critique: Fuel as a Solvent
Experts agree that the root cause of the deterioration is the dilution of the oil by gasoline leaking from the combustion chamber into the crankcase through the piston rings.
Consequences according to specialists:
– Reduced Protection: Gasoline not only reduces the viscosity of the oil, but also dilutes the protective additive package, decreasing the lubricant’s anti-corrosion and anti-rust ability.
– Chemical Attack: Gasoline, similar to alcohol, attacks the nitrile compound of the belt, causing it to swell and release residues. These residues, as they become gummy and sticky, clog vital passages, including the oil pump filter, resulting in a drop in lubrication pressure.
– Costly Breakdowns: If the belt breaks (on the EB2, which uses cylinder heads with interference valves), the damage can be catastrophic and it is better to replace the engine than to repair it. Repairs can be as much as $8,000 if there is breakage, or $2,000 if detected in time.
3. Advanced Preventive Maintenance and Solutions (BG Products)
Since the problem affects, in theory, 100% of the production of these first- and second-generation engines, specialists recommend preventive maintenance that is more rigorous than the official one.
BG Products recommends BG’ s Performance Oil Change service to address the root cause of the problem:
1. 109 EPR (Engine Performance Restoration): Designed to dissolve the hard carbon accumulated in the piston rings, aiming to restore the correct sealing of the combustion chamber. This is vital to minimize contamination of the oil by fuel in the crankcase.
2. 115 MOA (Motor Oil Additive): This additive increases oil protection (between 10% and 30% more) and acts as a shield against acids generated by fuel contamination. Provides extra protection to the oil-immersed belt to extend its service life and helps reduce oil evaporation.
BG 208 44K: This injection cleaner decarbonizes the combustion chamber and piston head. By restoring perfect atomization of the injectors, the amount of unburned fuel that could contaminate the oil is reduced.
General Expert Recommendations:
– Use only the approved and stipulated oil (such as 0W20).
– Change oil and filters every 10,000-15,000 km.
– Inspect the belt regularly, and even replace it before the new official interval of 100,000 km or six years.
4. The Stellantis Strategy and the Chain Debate
Stellantis has attempted to handle the dissatisfaction by offering an extended warranty (10 years or 175,000 km). However, experts see this as a “mere palliative”, as it does not eliminate the endemic engine failure, which means that the problem could recur after the warranty period is over.
The Design Decision (A Focus of Criticism): One of the most severe criticisms is Stellantis’ decision (with ex-PSA majority on its board) to continue investing in and developing the PureTech engine instead of adopting the FCA FireFly engines, which are considered phenomenal in efficiency and reliability. Stellantis’ argument was that the FireFly was “too new” or $500 more expensive to produce.
The Chain Conversion (PureTech Gen3): The most important correction was to replace the wet belt with a timing chain on newer versions (such as the 1.2L EB2 Gen3 and MHEV 48V variants). However, even this “solution” has been met with skepticism. Some specialists point out that, in order to minimize costs, a very small chain (8 mm links) was adapted to the same space as the belt. Under stress and heat, these links can elongate, creating new problems by misaligning the valve lift.
5. Final summary
Expert opinions on PSA’s PureTech engine range from recognition of an efficient base design to harsh criticism of a critical reliability failure associated with the wet belt. While Stellantis is attempting to correct course with the implementation of the timing chain on the newer generations and extended warranty on the affected ones, the main recommendation for owners of the problematic versions remains hyper-preventive maintenance, using additives that combat oil dilution by fuel, or, for those who have not yet purchased, avoiding the engine in its wet-belt version.