Many have noticed a strange effect: according to the specs, the car's engine is peppy, the numbers look convincing, but in reality, the car accelerates as if reluctantly. There's a pause at the start, a slight tremor at idle, and when compared to old naturally aspirated engines from the 90s, there's a feeling that cars used to drive more honestly.
The first thought in such a situation is a malfunction. But in most cases, everything works strictly according to the factory algorithm. Exactly as it was designed by the engineers, who in recent decades have had to adapt engines to extremely stringent environmental requirements. We are talking about the "Euro-5" and "Euro-6" standards, to which almost every production engine is adjusted today.
We will not discuss the need to care for the environment or the ideology of clean air. It is much more interesting to dispassionately understand exactly which technical solutions are used to fit the engine into the standards and what these solutions mean for the resource, reliability, and wallet of the owner.
Reason one: idling on the verge of stability
The most obvious moment is the revs of a warmed-up engine. On the tachometer, modern cars often show 600–650 rpm. At the same time, the body transmits a small, unpleasant vibration, creating the feeling that the engine is about to stall. This is not a defect or a flaw — it is intended.
First of all, the engine and gearbox mounts suffer from this mode. They are not designed for constant low-frequency oscillations and eventually begin to wear out faster: the rubber cracks, tears appear, after which the owner has to go to the service for an expensive replacement.
From the point of view of the engine's resource, the situation is also not ideal. At such low revs, the oil pump's performance is lower than at a higher idle speed. This means a decrease in the amount of lubricant supplied and a potential increase in wear. Additionally, constant vibration creates extra load on the timing chain and its tensioners.
There is no practical benefit for the owner here. The only gain is in the manufacturer's laboratory reports: there is a downtime phase in the certification cycles, and the lower the revs, the lower the CO₂ emissions. Fuel economy in real life is minimal, and the risk of accelerated wear is quite tangible.
Reason two: an engine that "breathes" its own exhaust (EGR)
The exhaust gas recirculation system forces the engine to re-ingest part of the exhaust into the intake. It sounds strange, but that's how it works.
The main blow is taken by the intake tract. The intake manifold and valves are eventually covered with a dense layer of deposits: soot from the exhaust mixes with oil from the crankcase ventilation system and settles inside the channels as a viscous black mass. As a result, the flow area decreases so much that the engine literally begins to "choke".
From the point of view of the resource, the consequences are even more serious. A coked intake leads to a loss of power and an increase in fuel consumption, but the main thing is that small abrasive particles of soot enter the cylinders and accelerate the wear of the piston group. This is where oil consumption and a reduction in engine life come from.
The system has environmental benefits: the addition of exhaust gases reduces the combustion temperature and reduces the formation of nitrogen oxides (NOx). Additionally, the warm-up time is reduced. But for the engine itself, EGR remains a risk factor with a delayed effect.
Reason three: particulate filter (DPF / GPF)
The particulate filter is designed to trap solid particles in the exhaust. In theory, it should be cleaned periodically by burning off the accumulated soot. In theory, everything looks beautiful, but in practice, difficulties arise.
If the car spends most of its time in city traffic jams, a full burn is simply not started. The filter gradually becomes clogged. Replacing it is very expensive. Additionally, the turbine suffers due to increased back pressure in the exhaust, and the engine oil can be diluted with fuel, which enters the crankcase during unsuccessful regeneration attempts.
Driving on diluted oil is a direct path to catastrophic wear. Liners, camshafts, and the piston group begin to break down at an accelerated rate.
From an environmental point of view, the effect is obvious: fine particulate matter is a dangerous carcinogen, and there is indeed less of it. For the owner, however, this is a complex and expensive unit. Buying a used car with a DPF or GPF is always associated with risk: a clogged filter is a financial mine.
Reason four: the "digital collar" of the transmission and engine
Many have experienced a feeling of delayed response: you press the gas, and the car seems to think before starting to accelerate. This is not a malfunction, but the result of environmentally friendly calibrations.
A telling example is the DSG robotic gearboxes, especially the dry DQ200, which was widely used on VAG models, including the Skoda Octavia. Such a transmission strives to engage a high gear as early as possible — up to seventh gear already at 60 km/h — and keep the engine at minimum revs. To get the gearbox to shift down, the gas pedal literally has to be pushed through. Initially, this was done to save fuel and reduce emissions, and at the same time to extend the life of the clutches.
The logical continuation of this philosophy was the widespread adoption of CVTs. From an environmental point of view, this is an almost ideal scheme: the absence of steps allows you to keep the engine in the most "efficient" zone. The price for this is a monotonous sound and, as a rule, not the most outstanding resource.
Not only the driver's nerves suffer here. If a sudden acceleration is needed, the response delay can be dangerous. The transmissions themselves also operate in modes close to the limit. For the engine, constant driving "under load" means an increase in detonation loads, which negatively affect its durability.
Reason five: Start-Stop system
The idea is simple: the car is standing — the engine is off, emissions are less. But if you look at it through the eyes of a mechanic, the picture becomes less rosy.
The starter starts working many times more often, the battery used is special and costs noticeably more, and the timing chain receives a shock load with each start. Yes, the components here are reinforced, but their repair and replacement are significantly more expensive than ordinary ones.
Each engine start is several seconds of operation with minimal lubrication. The crankshaft bearings suffer the most at this moment. In city traffic jams, there can be hundreds of such starts per day, which directly reduces the overall engine life.
This is not about rejecting environmental standards. It is important to understand that reducing emissions comes at a price — complicating the design, reducing reliability, and losing some of the driving pleasure. Knowing the weak points of your car, you can take care of them in advance and extend the life of the car.