Why do modern engines fail? 5 more reasons

We continue with the topic “What’s wrong with modern engines.” Get started via this link.

Direct and Combined Injection: Reliability Decreased

Initially, distributed fuel injection appeared in the intake manifold. A torch of atomized gasoline was directed to the intake valve, cleaning it of oil particulate deposits and combustion as a side effect.

Subsequently, to improve the performance of engines, they began to use direct or direct injection. The injectors inject the fuel under high pressure directly into the cylinders: you can optimize mixture formation and run the engine on lean mixtures. This is fuel economy.

But with such a system, a lot of problems arise. The main ones are increased requirements for purity and octane number of fuel, frequent replacement of fuel filters. Failure to adhere to this will result in premature wear and tear on an expensive high-pressure fuel pump and injectors. And also – unstable engine operation and poor starting, especially at low temperatures.

A special selection of engine oil is required, which ensures minimal carbon build-up – and this gives less protection against wear. Cleaning of the intake valves is required at least once every 100,000 km: otherwise the engine will literally suffocate from lack of air. If tightened with cleaning, the valve may remain open and bent.

A flushing system combined with a pump instead of a thermostat: maintainability and reliability are reduced

There has been a trend to move from simple thermostats to thermostats with heating elements, and on to the complete rejection of control using temperature-sensitive elements.

Control of coolant flow is transferred to purge mechanisms controlled by electric drives on electronic commands. The complexity of the system has increased enormously. The consumer is not hot or cold, except that some engines started to warm up faster.

A cooling system pump with integrated temperature control is comparable in number to a moped engine. And if something happens – a replacement assembly!

A cooling system pump with integrated temperature control is comparable in number to a moped engine. And if something happens – a replacement assembly!

Plastic suction pipes and plastic valves: not so durable and no longer trouble-free

Variable length intake pipes improve engine performance effectively. But most often in the plastic intake manifold, the channels are blocked by plastic mufflers.

Over time, the wear of moving joints in the presence of carbon particles and dust reaches supercritical values, causing the dampers to literally start to droop.

This reduces the accuracy of the control and often leads to the intake of unclean air into the engine.

Start-stop: durability is reduced

Most drivers do not like the system, which switches off the engine during short pauses in the movement of the car and then starts it again. Not without reason. The load on the starter and battery increases – and the additional starts are not indifferent to the engine. As you know, most of the shafts in it rotate on hydrodynamic bearings. That is, the shaft does not come into contact with the walls of the hole in which it works, and thanks to the oil wedge it rotates “contactless” with little friction and virtually no wear.

But all this is in operation. When the engine stops, the oil wedge disappears, and the shafts “fall to the bottom” – they are pressed against the surfaces. The crankshaft is pushed down by the weight and the camshafts are pushed up by the valve springs. After a short while, the Start-Stop system pulls them out of their homes. The result is the breakdown of metal microparticles and daily wear and tear.

Dual-mass flywheel: durability is reduced

Most modern cars with manual transmissions and any powerful engines, as well as all diesel cars, are equipped with dual mass flywheels. They make starting smoother, reduce vibration.

But the service life of such flywheels rarely exceeds the resource of the clutch disc. There have been instances where dual mass flywheels have failed before. It is impossible to drive with a broken dual-mass flywheel, and its replacement will cost quite a bit – up to 80 thousand rubles, or even more.


We have by no means listed all the problems of modern engines. Fact: Motorcycle building trends have changed. With the advent of computer aided design, manufacturers have been able to calculate the life of their motors quite accurately, saving a ‘margin of safety’.

The golden age of reliability ended in the 1990s, when European engine builders were not yet pursuing ultra-low toxicity standards; the Japanese had to conquer the car markets and so their cars were known for their reliability; the Americans provided a helping hand thanks to large-displacement engines with proven solutions such as the lower camshaft.

Today, almost all companies are not concerned about the operation of their machines after the warranty. Their job is to send the car owner in time to buy a new car, until the old one begins to “crumble” in sync with the end of the warranty.

Therefore, we do not recommend buying cars of recent years with high mileage after warranty without detailed diagnostics. Repairs can be costly and time consuming.

  • 5 problems of the most popular engine from Lada, Renault and Nissan – here.
  • The American Cyclo automotive chemicals and SUPROTEC additives help maintain the vehicle’s components and assemblies in good condition.
  • Read how to properly maintain a car in the books of the publishing house “Behind the wheel”.
  • “Driving” can also be read on Viber.

Source: Z R


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