Many car owners think about what a catalyst is in a car after this unit fails. Initially, catalytic converters began to be installed on the machines in order to reduce the detrimental effect on the environment of the exhaust gases that are formed during the operation of ICE. However, not all drivers approve of the installation of neutralizers, because the cost of this unit is quite high. In addition, due to the low quality of gasoline, it is necessary to repair it regularly.

Why do I need a catalyst in a car

A catalytic converter is one of the components of your car’s exhaust system. Why is there a catalyst in a car? It helps to reduce the percentage of harmful substances in exhaust fumes. These include carbon monoxide, nitrogen oxides and hydrocarbons.

Today, machines are installed neutralizers, which are made of noble metals. When the engine is running, the exhaust gases heat up the converter. The temperature of the catalyst of the car becomes quite high. As a result, noble metals burn out harmful substances, the percentage of which decreases. In this way, the established environmental requirements are observed.

What does a car catalyst consist of? From the case in which the base is in the form of ceramic or metal honeycombs. It is coated with a platinum-iridium alloy coating. Due to the honeycomb structure, the contact area of ​​the exhaust gases and the surface on which the catalytic layer is applied increases. An oxidizing reaction of carbon monoxide and a hydrocarbon proceeds in a catalyst. As a result, relatively harmless substances nitrogen and carbon dioxide come out of the exhaust.

Of course, a car can drive without a converter, but experts recommend mounting it when:

  • car age up to 5 years;
  • You pass the inspection yourself;
  • Planning a trip abroad (in this case, neutralizers must be installed on the car);
  • want car exhaust not to be harmful to the environment.

Varieties of automotive catalysts

All catalysts for the car exhaust system are divided into the following types:

  • Two Way Such a converter, carbon monoxide is oxidized to carbon dioxide, as well as fuel that has not burned or burned out, to water and carbon dioxide due to the combustion reaction. Typically, these two-way converters are installed on cars with diesel engines.
  • Three Way Such a converter was developed back in 1981. Its main goal is to reduce the amount of harmful substances that enter the environment. A three-way type neutralizer solves several problems at once. For example, it oxidizes carbon monoxide into carbon dioxide, as well as hydrocarbons that are not burnt, into water and carbon dioxide. It is also able to convert nitric oxide to oxygen and nitrogen.
  • Ceramic In this model, a design resembling honeycombs is installed. The neutralizing element made of ceramic is protected by a platinum-iridium alloy. What are the disadvantages of a ceramic unit? Many car owners believe that such a device is too fragile. For example, the honeycomb will deteriorate if a neutralizer hits during riding. In addition, if you drive through a puddle on a warm car, then water droplets will fall on a hot catalyst, and it will become worthless. Ceramic dust accumulates inside the device. It penetrates not only into the combustion chamber, but sometimes into the cylinders of the engine. catalytic converterThe main advantage of a neutralizer made of ceramic is budget.
  • Metal The design of such devices is quite strong and reliable. The metal converter is not afraid of mechanical stress. Made of metal, in the shape of a spiral, honeycombs are more elastic. But even such a reliable metal unit has its drawbacks:
  • Do not use low quality or leaded fuel.
  • Oils and antifreeze can enter the combustion chamber.
  • Technical fluids may only be used to flush systems from a reliable manufacturer.
  • Re-enriched fuel mixture may cause damage.
  • Continuous idling of the engine can also lead to malfunction.
  • Sports These are metal products with increased throughput compared to conventional metal or ceramic converters. Sports catalysts make a car 7–20% more powerful, of course, if a direct-flow exhaust system is mounted on the vehicle. Sports neutralizers comply with the environmental requirements of Euro 4 and 5. Such models have increased reliability. However, if you intend to purchase such a catalyst for a car, the price will be quite high.

Causes of catalyst malfunction

Neutralizing companies claim that they can be used for 100,000-150,000 kilometers. However, in reality, this unit can fail much earlier, especially if you live in a metropolis and constantly stand in traffic jams.

Why can the neutralizer become unusable? The fact is that the vehicle’s catalyst device is a filter. And the filter needs to be changed regularly.

The service life of the unit will be reduced if the ignition system is malfunctioning. Such a problem is usually detected on Ford and VAZ cars. If the ignition is set incorrectly, misfires will occur. As a result, the fuel mixture burns only partially. A huge amount of soot is formed, which accumulates in the converter. The best solution is to clean it. But this will not help if the bobbin is melted.

Damage to this unit may occur if you use low quality fuel. It will not completely burn out. The after burning process will occur in the collector, and directly in the converter. The micro particles clog the filter and air cannot pass through it.

The converter may become clogged with combustion waste. This usually happens when the motor starts to consume too much oil. Indeed, during its combustion, corrosive black smoke is formed. As a result, the converter experiences the harmful effects of not only combustion waste, but also oil.

Car Catalyst Malfunction Symptoms

How to find out that the catalyst exhaust system of a car is worthless?

  1. The “Check Engine” indicator lights up on the dashboard. It lights up if the system detects any engine error. In this situation, this is due to incorrect lambda probe sensor readings. To verify that the cause of the malfunction is the catalyst, you must diagnose it with a scanner.
  2. Car power drops. If the catalyst in the car is not in order, the car will, twitch, traction will decrease. This happens because the throughput of the converter has decreased. After all, the cells are partially destroyed, they were baked, the passage of exhaust gases clogged. All this leads to the fact that the engine “does not breathe.”
  3. Extraneous sounds under the bottom. Do you hear knocks that occur at high revs or when starting the car? This usually happens when ceramic cells begin to break down. Fallen off particles hit the walls of the catalyst, because they are affected by the gas flow, as well as centrifugal forces.
  4. Weak or even pressure of the gases coming from the muffler. If the catalyst in the car is operating normally, then, placing your palm against the exhaust pipe, you will feel that the outgoing gas stream is pulsating. This is because the exhaust valves operate in turn. Have you noticed that the gas flow is weak or there is no ripple? So, the neutralizer cells are destroyed.

The catalyst in the car cannot break instantly. Before it finally fails, you will notice that the malfunctions described above have appeared.

How to check the catalyst for a malfunction

You can do the check yourself. However, to carry out this procedure, experience and diagnostic tools will be required. For an accurate diagnosis, it is best to visit a specialized service center. How is a catalyst test performed in a vehicle?

  • Inspect the catalytic converter Visually inspect the outside of the unit. If you find mechanical damage, dents, chips, then, most likely, the cells inside have also deteriorated. Unfortunately, with the help of an external inspection, it will not be possible to determine with 100% accuracy the state of the cells. Therefore, you have to remove the converter. In addition, a clearance test can be performed. If the honeycomb is in order, then the catalyst in the car is working. To diagnose this way, not every car model will turn out, because the catalyst device on different cars may differ.
  • Check back pressure To conduct such a check, a special device is required – a manometer. With it, you can measure the exhaust pressure. If it is above normal, then there is a malfunction.

    First you have to get a lambda probe and connect a pressure gauge instead.

    Important! The connection must be tight. We start the engine, increase and hold revolutions to 2.5-3 thousand for 10 seconds. The optimum pressure is not more than 0.3 kg per square centimeter. Did the pressure gauge show a higher pressure? So, the catalyst in the car is clogged.

  • We diagnose the catalyst in the car using a motor tester A diagnostic tool will be required to verify that the components and components of the vehicle are in good condition using an oscillogram. The device is mounted instead of spark plugs, then the engine is started. The data obtained from the device will show the state of the catalyst.

Cleaning or flushing the vehicle catalyst

This procedure will help if you perform it when the cells are in normal working condition. If they splintered or collapsed, then washing and cleaning will not help. The only way out is to replace the catalyst in the car or mount an inexpensive flame arrester.

1. Preventive cleaning of the catalyst

Auto mechanics and car owners usually use two methods to flush a car’s catalyst from oil and soot deposits:

  • Preventative cleaning with detergent. It is recommended to perform it every 70,000-100,000 kilometers. It is not necessary to remove the catalyst from the vehicle.
  • Flushing the converter, in which the unit is dismantled and disassembled.

How to rinse a car catalyst for prevention? In car dealerships, you can find tools designed for this purpose, for example, Whynn’s Catalytic Cleaner. Pour liquid into the fuel tank, and continue to drive the car. After such cleaning, soot will come out of the converter along with the exhaust gases.

To carry out mechanical cleaning, you need a compressor, as well as fine sandpaper. Of course, using such a cleaning method, it will not be possible to eliminate internal pollution – carbon deposits in ceramic honeycombs.

Many car owners use the chemical composition to flush the catalyst in a car that they previously dismantled. For example, ABRO aerosol, which is used to clean the carburetor, is suitable. In some cases, car owners use kerosene, ethanol, and so on, but no one guarantees that such washing will not harm the converter. A harsh detergent can spoil the catalyst, and you have to spend a large amount on the purchase of a new unit.


To flush the catalyst using Wynn’s or any other means, it is necessary to fill the composition in the fuel tank, and then refuel the car. You do not have to make an effort: the neutralizer cells will clean themselves during the operation of the car, and the pollution will come out through the exhaust pipe.

2. Cleaning with dismantling

Sometimes, to flush the catalyst in a car, you have to remove it. For this, the vehicle must be driven onto a flyover. We disconnect the lambda probe, then we unscrew the clamps with which the converter is mounted on the exhaust pipe or exhaust manifold. Then you need to follow these steps:

  • Using a compressor, blow the catalytic converter from both sides. Pressure should be 7–9 bar.
  • Pour ABRO aerosol foam into the honeycomb, which is designed to clean carburetors. Foam should be poured through both nozzles.
  • Wrap up the unit with a cloth and wait 20 minutes.
  • Turn on hot water, the pressure should be strong enough. Then flush the inside of the unit. After flushing, blow with a compressor.
  • Repeat these steps again. After that, the converter should dry. You must see the honeycombs through and through. Mount the catalyst.

Note! Depending on your vehicle model, the lambda probe may be located inside the catalyst. Then, before flushing the element, you will have to disconnect the sensors and clean them of soot.

Failed to remove contaminants from the catalyst with aerosol foam? Then pour diesel fuel or kerosene into the tank and lower the converter there for 12 hours, maybe for a day. To make the cleaning as effective as possible, add acetone or solvent 646 in a 4: 1 ratio to the diesel fuel. After 24 hours, clean using aerosol foam using the above technology.

If you want to clean the unit mechanically, you will need fine sandpaper, as well as a compressor, to purge the converter from time to time. Of course, the mechanical cleaning method does not remove carbon deposits from within the catalyst.

Sometimes car owners do not wash the converter, but simply pierce a clogged honeycomb with a sharp thin awl. Performing such a procedure is justified only when none of the listed cleaning methods have helped.