Stellantis Quietly Went Back to the Chain - And Never Told PureTech Owners

£6,000. That is the bill to replace an engine that won its class at the International Engine of the Year awards four years in a row. Not a bad engine that slipped through, the most decorated small petrol engine in Europe. It is called the PureTech, 1.0L and 1.2L. Three cylinders, fitted to Peugeot, Citroen, Vauxhall, Opel, DS, Fiat and Jeep. Millions of them, sold across Europe since 2012. And it destroys itself from the inside, using a component the industry had already sold 50 years earlier. Stay with me to the end, because this one gets worse the further you go in. I'm going to show you the design decision taken to save fuel and cut noise, that ends with a seized engine and a repair bill worth more than the car it sits in, the 3.25L of oil doing a job that needed more, a compensation scheme Stellantis built for the owners it failed, and the conditions written into it that decide who actually gets paid. The fire recall on the engine that was supposed to be the fix, and the quiet reversal, where the company that spent a decade telling everyone this design was sound went back to the parts it had replaced. Every figure in this is real, and every one is worse than the last. Let's begin. To understand how bad this got, you have to understand how good everyone thought it was. Go back to the early 2010s, the whole industry had decided the future was small, emissions rules were tightening across Europe, tax was moving to carbon dioxide, and every manufacturer was hunting for a way to build a smaller engine that still felt like a big one. The word for it was downsizing. PSA Peugeot Citroen built the answer. A 3-cylinder petrol engine, turbocharged, direct injection in 1L and 1.2L forms. Light, compact, efficient on paper, and quick enough in the real world that nobody missed the 4-cylinder it replaced. The industry loved it. It took its category at the International Engine of the Year again in 2016, again in 2017, and again in 2018. Four years running, judged by motoring journalists from around the world against everything else built at that size. And it went everywhere. Peugeot 208, 2008, 3008, Citroen C3, C4, Berlingo, the Vauxhall Corsa, and the Mokka. Opel across the continent, DS, Fiat, Jeep. When PSA merged with Fiat Chrysler in 2021, the engine came with it and spread further still. This was not a niche unit in one unloved hatchback. For a decade, if you bought a small petrol car from one of Europe's biggest manufacturers, there is a strong chance that this is what was under the bonnet. That is the Hyte, an award-winning engine in millions of cars, carrying the reputation of 7 brands at once. The award was for the idea. Nobody was testing the belt. Every engine needs something to keep the top half turning in time with the bottom half. Get it wrong by a fraction and the valves meet the pistons and the engine is scrap. For most of motoring history, there were two ways to do it. A chain, running in oil inside the engine, lasting the life of the car. Or a rubber belt, running dry on the outside, replaced every few years as a service item. The chain was heavier and more expensive. The belt was cheaper and quieter, but had to be changed. PSA took a third route. Put the belt inside the engine, running in the oil. There was a real engineering case for it, and it was worth understanding rather than dismissing. Oil reduces friction, and less friction means less fuel burned and less carbon dioxide out of the exhaust. At a time when a single gram per kilometre could decide a tax band, that mattered. The oil also deadened the noise, which is the thing three-cylinder engines are worst at. And a belt inside the engine takes up less room than a chain and its tensioners, which matters when you are packaging a small engine into a small car. Lower emissions, quieter running, tighter packaging, on the drawing board is not a stupid idea. Ford reached the same conclusion with its 1-litre EcoBoost. So did Renault. The design was signed off. It went into production, and for the first few years of a car's life, it did exactly what the engineers promised. It worked exactly as designed. That was the problem. Here is what nobody accounted for. A modern direct-injection petrol engine sprays fuel into the cylinder at enormous pressure. When the engine is cold, not all of it burns. Some of it washes down the bore, past the rings, and ends up in the sump, mixed into the oil. Every engine does this to some degree. It is called fuel dilution. And on a long run at temperature, most of it boils back off. Most of it. On a long run. Now think about how a Corsa or a 208 actually gets used. School run, supermarket, four miles into town and four miles back. The engine barely reaches temperature before it's switched off again. The fuel goes in, and it stays in. So the oil in the sump is not really oil anymore. It's oil with petrol in it, and petrol is a solvent. And sitting in that solvent, turning over every second the engine runs, is a rubber belt. The rubber softens, the surface breaks down, fine cracks open across the face of it and the edges begin to fray. And as it frays, it sheds. Tiny black particles of belt, released into the oil, circulating through the engine with every rotation. Now the oil capacity matters. This engine holds around three and a quarter litres. That's a small volume for a turbocharged engine. And a small volume means everything in it is concentrated. Less oil to dilute the fuel, less oil to carry the debris. The same amount of shed rubber in half the oil is twice the problem. That debris has to go somewhere. At the bottom of the sump there is a strainer. A fine mesh over the pipe that feeds the oil pump. It's there to catch anything solid before it reaches the moving parts. It does its job. It catches the rubber. And it keeps catching. Until the mesh blocks. When the strainer blocks, the pump cannot draw enough oil. Pressure falls. And an engine without oil pressure is running metal against metal in the bearings, the camshaft, the turbo. It does not last long after that. Nothing warns you. The first symptom is the last one. So the belt sits in oil, the oil eats the belt, and the belt kills the engine. Now ask the obvious question. What did this replace? A chain. A steel timing chain, running in oil, doing the exact same job. And a chain does not care about fuel dilution. It does not soften, it does not fray, it does not shed particles into the sump. Fitted properly, a chain lasts the life of the engine and you never think about it once. That is the technology the industry had settled on decades earlier. Not because engines lacked imagination, but because it worked. The chain is heavier, it costs more to make, and it makes a bit more noise. Those were the trade-offs, and for 50 years manufacturers accepted them. Because the alternative was an engine that could destroy itself between services. PSA decided the trade-offs were no longer worth it. Take the chain out, put a belt in the oil, save the friction, save the noise, save the weight, save the money. And here is the part that tells you everything. Stellantis has gone back to the chain. The current generation of this engine, the one being fitted to new cars now, does not use a wet belt. It uses a timing chain. The company that spent more than a decade selling this design, defending it and telling owners it was fit for purpose, has quietly redesigned the engine around the exact component it removed in the first place. They did not announce it as a correction. There was no admission, no apology, no statement that the previous design had been a mistake. It simply changed. On new production. And the old engines carried on doing what they were already doing. Think about what a design reversal actually costs. New toolings, new castings, revalidation, millions of euros and years of engineering time, spent on doing a decision the company was still publicly standing behind. You do not spend that money on an engine you believe is fine. Now the part that lands in the driveway. When this engine fails, it does not fail cheaply. Best case, caught early, you were looking at a preventative belt change with the sump off and the strainer cleaned out. That is not a quick job. The belt is inside the engine, which means draining the oil, dropping the sump and stripping the front of the engine to reach it. Labour alone runs into the hundreds. Worst case, and it's a common case, the strainer has already blocked and the damage is done. Then you are not replacing a belt, you are replacing an engine. £3,000, four, six at a main dealer with a new unit fitted. Now hold that number against the car it is sitting in. A 2017 Corsa, a 2018 208, nine years old, honest mileage, tidy enough. It is worth two, maybe £3,000 on a good day. Repair costs more than the car. That is the entire situation in one line. The bill is bigger than the asset, so the economically rational thing to do is scrap a car that is otherwise completely serviceable, with good tyres and a fresh MOT and nothing else wrong with it. And this is not a rare event on an unloved model. This is the Corsa, Britain's best-selling supermini, year after year, sitting on driveways in every town in the country. Multiply the cost of one failure by the number of these engines on European roads and you are looking at one of the largest single transfers of cost from the manufacturer to its own customers in modern motoring. Stellantis did respond. There is an extended warranty, running to 10 years from first registration with a mileage cap, covering the belt failure and the damage it causes. There is a compensation scheme. Now read the conditions. The warranty extension and the compensation scheme both come with requirements attached, and the requirements are where this stops being an engineering story and starts being something else. To qualify, the car must have been serviced in line with the manufacturer's maintenance plan, every interval, on schedule, to specification, and the diagnosis and repair have to go through the authorised dealer network. Listen to that again and think about who it describes. A nine-year-old Corsa, third owner, maybe fourth. It left the franchised dealer network years ago, because that is what happens to every small car once the warranty expires and the main dealer servicing costs more than the independent down the road. The paperwork is a folder of receipts from a garage in town. Some of the stamps are missing because a previous owner did not keep them, or the garage did not stamp the book, or the book was lost with the last logbook change. That car is exactly the car this engine kills, and that car is exactly the car the conditions exclude. The people best placed to claim are the ones who bought new, kept it inside the dealer network, and have a complete stamped history. Those owners exist. They are also the owners least likely to still have the car by the time the belt lets go, because the failure arrives years down the line, in the hands of somebody who bought it second-hand and inherited a fault they had no way of knowing about. Then there is the window. The scheme covers repair costs incurred between 1st January 2022 and 31st December 2024. Fail before that, and you are outside of it. Fail after it, and you are outside of it. Fail during it, and you still need the service history and the dealer diagnosis to get through the door. None of this is hidden. It is all published in plain language, on the company's own claims platform. That is what makes it worth saying out loud. This is not a conspiracy uncovered in a leaked memo. It is a remedy designed in the open, with conditions that quietly filter out most of the people it appears to be for. A scheme that pays the owners who can afford to lose the money, and excludes the ones who cannot. And while those conditions were being written, it is worth knowing where the money was going. Carlos Tavares ran this company through the years the engine was failing in the field. In 2023 alone, his total pay came to more than 36 million euros. Across his time as chief executive, he took well over 100 million out of the business. His own shareholders were not comfortable with it. In 2022, a majority of them voted against his pay package. The vote was advisory. Nothing changed. One man drew 36 million euros out of this company in a single year. An owner in Britain with a gap in the service book of a nine-year-old Corsa was told the engine was their problem. That is the shape of it. The cost of the decision did not land on the people who made it. Now, the part that most coverage leaves out, and it matters if you want the truth rather than just the outrage, Stellantis did not invent the wet belt. Ford put one in the 1-litre EcoBoost, an engine fitted to the Fiesta and the Focus, sold across Britain in enormous numbers. It had its own belt degradation problem and its own trail of wrecked engines behind it. Renault went the same way with the 1.3 petrol. This was not one company doing something reckless while the rest of the industry watched. It was an industry-wide answer to an industry-wide problem, which was carbon dioxide legislation tightening faster than engine technology could comfortably follow. So why did this one become the scandal? Scale is part of it. 7 brands, 13 years of production, millions of cars. When the same fault sits under that many bonnets, it stops being a known issue on a forum and becomes a national one. But the engineering choices around the belt matter too. That small sump concentrates everything that goes wrong in it. Combine it with the service intervals these cars were sold on, and the belt is sitting in the harshest version of an already environment. And there is one more thing worth saying plainly because it cuts against the story. Stellantis is not finished. The company returned to profit in the second quarter of this year, carried largely by North American sales. This is not a business collapsing into administration, which is what makes the owner's side of it worse, not better. The money exists, it is simply not going where the damage is. So where does it stand today? The chain-driven of the engine is in production and by every indication it works. New buyers are not exposed to this, that part is genuinely fixed. But fixing the new ones does nothing for the old ones, and the old ones are the ones on the road. Millions of cars across Europe, most of them past the point where the manufacturer has any obligation, working their way toward a failure that has already been designed out of the cars behind them. The compensation window has closed, repairs after the end of 2024 are outside of it, and the wider picture at Stellantis is not settling down. On the 17th of August this year, the company recalled around 955,000 vehicles worldwide after a software fault that stops the reversing camera displaying when you select reverse. 848,000 of those are in the United States. That is a separate problem to this engine entirely, and that is rather the point. The recalls are not slumming down. The market has noticed. On the same day the recall was announced, Citi cut its price target on Stellantis stock. The share price has lost close to half its value over the past year. The company is repairing itself. The cars are not. So I want to hear from you, because this community has more of these engines on its driveways than any boardroom in Paris or Turin will ever admit. Have you ever had one? What was it in, what year, and what did the bill come to? And if you went through the claims process, did you get anything back, or did the service history rule you out before anyone even looked at the car? And here is the question worth arguing about in the comments. Stellantis engineered this fault out of its new engines and never once called it a fault. Is a silent redesign an admission, or is it just a company quietly moving on and hoping nobody joins the dots? Tell me below, and tell me where in the world you are watching from.