What does refueling with low-quality fuel lead to?

Saving on fuel quality leads to negative consequences. Even one refueling with bad fuel can cause significant damage to the car.. Formulas like: “I’ll fill up cheaply three times and with quality gas once” don’t work and lead to serious problems.

Eliminating the consequences of using low-quality fuel can take a lot of money and time. Problems can arise not only with the fuel system, but also with other engine mechanisms. That is why, especially in modern cars, you need to use only high-quality fuel purchased from a network of gas stations with a good reputation.

The fuel system is primarily affected by low-quality fuel.. But other malfunctions are also possible: in the cylinder-piston group, gas distribution mechanism and exhaust gas system. Let's look at what damage the use of cheap fuel can cause.

Fuel system

Cheap fuel often contains mechanical impurities, in other words, garbage. The simplest malfunction that can arise from this is that the mesh in the fuel tank becomes clogged.. If this happens, the car loses power, or generally only works at idle.. By cleaning the fuel intake screen in time, you can save the fuel pump. And if you continue to drive with such a malfunction, the fuel pump will quickly fail.

Filling with low-quality fuel can clog the fuel pump screen, and this is one of the most minor problems

Another malfunction associated with low-quality fuel is a clogged fuel filter.. It is quite easy to fix, just replace the filter. Usually the fuel filter is changed through one maintenance, but if low-quality fuel was filled and the fuel intake screen was clogged, the fuel filter needs to be changed out of turn.

Dirty fuel injectors are a more serious problem.. In most cases, cleaning them on a special stand helps, but sometimes replacement may be necessary.. Fuel injectors are not cheap.

The high pressure fuel pump is used in both diesel engines and gasoline engines with direct injection systems. This is one of the most expensive parts of the fuel system, which fails due to low-quality fuel. Replacing or restoring a high-pressure pump takes a lot of time and is not cheap at all.

Cylinder-piston group

Many modern cars have aluminum engine blocks, and the cylinder walls are coated with a special coating.. This design makes the cylinder walls very hard and resistant to friction.. But there is a downside to the coin — the hard coating is not adapted to the shock loads that occur during detonation.

Detonation leads to destruction of cylinder walls

Low-quality gasoline, with a lower octane number than stated, tends to ignite prematurely.. This phenomenon is called detonation. It is this that destroys the coating of the cylinder walls of modern aluminum engines.. When the coating is damaged, scoring occurs on the cylinder walls and pistons. Even one refueling with low-quality fuel is enough to destroy the fragile coating of the cylinders.. Repairing or replacing the engine of a modern car is a very expensive pleasure and can hardly be compared with the “savings” on a tank of fuel.

Therefore, when refueling, be sure to follow the manufacturer’s recommendations.. If it is recommended to use A95 gasoline, do not use gasoline labeled A92. In addition, you can check the fuel passport. In the WOG filling station network, such documents are always available in the consumer corner. Also take an interest in the independent fuel reviews that Avto24 regularly publishes.

Gas distribution mechanism

Low-quality fuel has a detrimental effect on the parts of the gas distribution mechanism, namely the valves. Incomplete combustion of fuel forms carbon deposits that prevent the valve from closing completely.. As a result, the valve may burn out.

Poor quality fuel can cause valve damage

Valves are not very expensive, but replacing valves is not a cheap operation and requires disassembling the engine.. Typically such repairs take at least several weeks.

Exhaust system

Modern cars are equipped with catalysts, and diesel cars are also equipped with particulate filters. In addition, oxygen sensors (lambda probe) are installed in the exhaust system.

Incomplete combustion of fuel in the combustion chamber leads to increased load on the catalyst, because the remaining fuel burns out on it. In this case, the catalyst quickly fails.

The use of low-quality fuel leads to rapid failure of the catalyst

Very often, after refueling with low-quality fuel, the Check Engine light comes on.. This indicates that the engine is not working properly.. Such a signal most likely can come from a knock sensor, or from a lambda probe.

If the Check Engine lights up on the instrument panel shortly after refueling, you need to drain the low-quality fuel and refuel with a high-quality one. Continued operation of the vehicle with a signal indicating improper engine operation can lead to serious damage.


It’s not worth refueling with cheap low-quality fuel. By saving 100-200 hryvnia on a tank, you can get a very bad result in the form of these problems. The costs of solving them are hardly worth such dubious savings.