Decoding the success of the 0.9 TCe engine in Renault and Dacia cars: A look into construction, common faults, and LPG compatibility

The engine has been integrated into models such as the Renault Captur and Twingo, Dacia Logan and Sandero, Nissan Micra, and Smart Fortwo and Forfour. Factory configurations with an LPG installation were available.

The engine's consistent offering without major changes until 2020, and the fact that the newer 1.0 TCe engine is merely an enhanced version of this design, speaks to the unit's success, at least from the manufacturer's perspective. Let's concentrate on the older variant with a displacement of 898 cc.

The engine, known as H4B, features an aluminum block, three cylinders, and two camshafts in the head, driving a total of 12 valves. In essence, it's a scaled-down version of the 1.2 TCe (H5F) engine. Although it's a Nissan creation, the 0.9 TCe engine is considered French since it was jointly developed by the two manufacturers and gained popularity mostly in French and Romanian cars. Moreover, many parts bear the Renault brand, not Nissan.

Despite being perceived as a typical downsizing model, direct injection was not used. However, it does include a turbocharger, combined with an exhaust manifold and supported by an intercooler. Variable valve timing phases are present — on the intake side. Likewise, there's a start&stop system (with an energy recovery feature) and low-resistance materials (for instance, graphite on pistons).

The timing is chain-driven, with two sliders and a tensioner. A smaller secondary chain powers a variable capacity oil pump.

In many aspects, this Japanese-French engine is a highly refined model that seldom causes major issues. Its fuel and ignition systems are practically faultless, likely attributed to its use of indirect injection. The charging system is also durable despite heavy usage. Notably, the turbocharger is cooled not just by oil but also by liquid.

Oil change frequency significantly impacts the durability of this component – the more frequent, the better. It's advised to change it every 6213 miles or once a year, albeit the manufacturer has cited a usability period of 18,641 miles or 2 years. In some cars, the computer offers reminders about this.

Does this engine have any common faults? Not many. One of them is the sealing of the thermostat housing made of plastic, as is most of the engine’s equipment. These are uncommon occurrences, but they do happen. Hence, checking the coolant is advisable. If it's missing, the housing is likely the culprit.

The heat exchanger cracking is even rarer. The symptom here is oil leaking into the coolant. The worst damage, however, can often come courtesy of mechanics if they lack the necessary experience, damaging one of the numerous plastic engine parts, though the parts are inexpensive and widely available for replacement.

If there's oil in the intake manifold (which is made of plastic) for some reason, pay attention to the valve in the crankcase ventilation system. It sometimes gets stuck, letting too many fumes from the crankcase.

Another frequent issue is the premature stretching of the timing chain. The manufacturer designed the timing drive to last the engine's entire operating period, so any wear and tear are considered a defect. The usual cause is a clogged tensioner, regardless of mileage. The engine then produces a distinctive rattling sound. Replacing the timing is a full day's work for a mechanic plus around $400 for a set of parts. Once you repair this area, it's advisable to replace all components.

The 0.9 TCe engines, as installed in Renault and Dacia cars, came with a factory LPG installation. It is a Landi Renzo system equipped with top-tier components. Adjusted specifically for this engine, user experience confirms it does not harm the valve seats.

However, keep in mind that the valves here are adjusted using so-called push glasses. This operation might become necessary and may cost over $265.

If you're weighing the option of buying a car equipped with a 0.9 TCe engine, my advice for you is that if anything is going to cause issues, it won't be the engine. It's the finest thing that has emerged in the Renault or Dacia lineup in the past decade.

In reality, a well-maintained engine not running on gas can easily withstand mileages in the range of 155,342 - 186,411 miles. So far, there aren't many cars with higher mileages, but the fact that not much needs to be done with the engine over these 186,411 miles earns it high praise.

So, what's the secret of this engine? It lies in a straightforward design and lightweight cars it's used in. Unlike the 1.0 EcoBoost or arguably the 1.2 PureTech engine, which can be viewed as competitors, the 0.9 TCe units were never used in compact cars, and the largest (and heaviest) model equipped with this unit is the Renault Captur.

Another strength is the unit’s simple construction and equipment. There aren't any advanced exhaust cleaning systems, an array of sensors, or complex recirculation systems. Direct injection isn't featured either, which can cause several combustion process problems. This partially explains why this engine had to be discontinued in 2020, as it only met the Euro 6 standard. This consequently ended the production of the fourth-generation Renault Clio and the popular Dacia Sandero, where this engine was widely installed.

Its successor, the 1.0 TCe engine, shows promise. It adheres to stricter exhaust cleanliness standards and has been inserted under the hood of larger models like Dacia Duster. Will it be as competent as its predecessor? A few more years should provide the answer to that question.