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The Essential Guide To Catalytic Converter


You don't have to worry if you don't understand what a catalytic converter is. While the technology isn't new and can be found in almost every car on the road today, there's no reason catalytic converters should be on the minds of most drivers. They work in the background, cleaning toxic gases from your car's exhaust emissions by chemical reactions. There's nothing to be concerned about unless it breaks or, as has become more normal in recent years, someone tries to steal it. From how they work to the materials and precious metals used in them, we cover everything you need to know about catalytic converters in this guide.

What Is A Car Catalytic Converter?

A catalytic converter is nothing but an exhaust emission control device which helps to reduce the toxic gases and pollutants in exhaust gas from an internal combustion engine. This is then converted into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are generally used along with the internal combustion engines which are fuelled by either gasoline or diesel, which includes lean-burn engines and kerosene heaters and stoves.

If you want to know about the difference between Catalytic Converters and Mufflers, then all you have to do is visit our What Is The Difference Between Catalytic Converters and Mufflers? section. 

Where Is My Car Catalytic Converter Located?

In most vehicles, the close-coupled catalytic converter is found near the engine's exhaust manifold. As the converter heats quickly, because of its exposure to the boiling exhaust gases, this will help to reduce adequate emissions during the warm-up period of the engine.

What Materials Are Used For Making Car Catalytic Converter?

The catalytic converter comprises several materials. According to the vehicle, the catalyst core or the substrate will vary.

  • For example, when a vehicle’s catalytic converter is used in automotive the core is a ceramic monolith which has a honeycomb like structure.
  • Ceramic cores can be inexpensive when manufactured in large quantities.
  • Metallic foil monoliths are generally made of iron-chromium-aluminium combination, and is utilized in some applications.
  • Metallic cores cost less when they are manufactured for use in small production runs, like, sports cars where low back pressure and reliability under constant high load is very essential.
  • Both these components are designed in such a way to provide a high surface area so that it can support the catalyst wash coat.
  • The catalyst wash coat acts as a carrier for the catalytic materials, which is utilized to spread the materials over a high surface area.
  • Titanium dioxide, aluminium oxide, silicon dioxide, or a combination of silica and alumina are utilized. Before it is applied to the core, the catalytic materials are suspended in the wash coat.
  • In order to increase surface area, wash coat materials have rough, irregular surface so that the catalytically active surface can be maximized, which makes it available to react with the engine exhaust.
  • Mostly precious metal such as platinum, palladium and rhodium are used by the catalyst in the converter.
  • Platinum is used both as a reduction catalyst and an oxidation catalyst.
  • Though platinum is widely used and serves an active catalyst, it is very costly and will not be suitable for all applications.
  • Rhodium will be utilized as a reduction catalyst, whereas palladium will be utilized as an oxidation catalyst.
  • Sometimes, cerium, iron, manganese and nickel are also utilized. However, few companies will restrict to use them.

How Does My Car Catalytic Converter Work?

The catalytic converter comprises a core of ceramics punched with pores which measures less than 1mm. The pores are coated with powdered catalysts which comprise certain metals like platinum, palladium and rhodium. As the pores lie close to the engine, they get quickly heated and the chemical structure of the exhaust gases which passes through it will also change.

Both the carbon monoxide and hydrocarbon is broken down and converted into carbon dioxide and water, respectively. Catalytic converters are very effective such that the difference in emission readings for cars with and without converters is very considerable. The happiest news is that catalytic converters have a decent life expectancy, yet it has to be periodically checked for internal and external damages.

What Are The Common Car Catalytic Converter Problems?

It can be hard to fix a catalytic converter. This essential emissions system component can consume more fuel, as it will gradually lose its efficiency and affect the power production of the engine. 

The catalytic converter sits in front of the muffler in the exhaust system. It’s very small, and the chamber is oval-shaped, which is packed with materials like platinum or palladium in a honeycomb-type structure. This makes sure that sufficient exhaust gas is available to pass over these metals, so that they can be easily changed into less harmful emissions before they leave out of the vehicle through the tailpipe.

Here are the 3 common causes of catalytic converter problems.

Un-burned Fuel

  • Heat can cause damage to any engine component. Hence, it’s not a surprise that it is one of the most common causes for the failure of the catalytic converter.
  • As the engine exhaust is already hot, when you add contaminants such as un-burned fuel, it can enter into the vehicle’s exhaust system when the motor is running too rich.
  • This fuel might end up burning the inner side of the converter.
  • This will eventually damage or melt the honeycomb structure which is needed for the catalyst metals to carry out their job, which leads to blockage or restriction in the exhaust flow.
  • If the engine misfires or if a warning code for a bad oxygen sensor appears, then it is best to take care of the issue before it can lead to the failure of the catalytic converter.

Coolant Leaks

  • If the coolant is leaking into the combustion chamber of the engine, then it is a serious problem which can eventually damage the motor.
  • Even if it is dripping from the head gasket, it will send the coolant into the vehicle’s exhaust system.
  • Eventually it will get clogged in the catalytic converter and the materials inside it will get contaminated until they are no longer effective.
  • If the coolant disappears from your engine’s reservoir or if you notice any white smoke in your exhaust, then it indicates broken head gasket, which needs immediate replacement.

Oil Consumption

  • In today’s vehicle, engine consumes more oil.
  • This usually happens when the piston rings lose their ability to get properly sealed up when the miles pile up or if the valve gets stuck.
  • Also, small design issues and worn out engine components can cause this failure.
  • The oil which has been burnt in the engine will start flowing through the vehicle’s exhaust system, where it will significantly cause catalytic converter failure in similar way to a coolant leak.
  • A visible black smoke or indications that your car is using a more oil in between changes is a sign that you will end up reducing the efficiency or permanently damaging the converter.
  • It can be a nuisance to replace the converter, but it’s definitely worth it, when you consider the decrease in power and increase in fuel consumption it can cause when it malfunctions.

What Are The Symptoms Of Bad Catalytic Converter?

A catalytic converter helps in reducing vehicle emissions and pollution. It is a metal canister fixed in the exhaust system, which is filled with a chemical catalyst such as platinum and palladium mixture. It helps in converting the vehicle’s emissions into non-harmful gasses. A faulty catalytic converter will show one of 5 symptoms which can alert the driver that the catalytic converter needs replacement.

  1. Reduced Engine Performance - Reduction in engine performance is one of the first symptoms commonly linked with a bad or faulty catalytic converter. The catalytic converter is built in the exhaust system of the vehicle, and as a result, it can harm the performance of the engine if there are any problems. A converter which is clogged will limit the exhaust flow, whereas a cracked converter will leak harmful gas. Either of these faults can negatively affect the performance of the engine and reduce power, acceleration and fuel economy.
  2. Rattling Noise - Another symptom of a bad or faulty catalytic converter is rattling noise from under the vehicle. If a catalytic converter has become old or if it has been damaged internally due to excessive rich fuel mixtures, then the catalyst which is coated with honeycomb meshes on the inner side of the converter will eventually collapse or break apart, this can cause a rattling noise. This noise will be more obvious when you start the vehicle and will gradually worsen over time.
  3. Sulphur Smell from Exhaust - The sulphur-containing gasoline will become hydrogen sulphide during engine combustion. A catalytic converter which is working properly will convert hydrogen sulphide into odourless sulphur dioxide. If it is faulty then you will notice a sulphuric, rotten egg-like smell coming from the exhaust. The bad odour is produced by the unburnt fuel which is left in the exhaust by the bad catalytic, and can give rise to dark exhaust smoke.
  4. Check Engine Light Comes On - A faulty catalytic converter can cause the illumination of the check engine light. The oxygen sensor and the air-fuel ratio sensor in the modern vehicles will look after the efficiency of the catalytic converter by tracking the gas levels in the exhaust. If the computer identifies that the catalytic converter is not functioning properly, or not catalyzing the exhaust gases as needed, it will set off the check engine light to show to the driver that there is a problem. There are also several other issues which can activate the check engine light. So it is always best to have your vehicle scanned for diagnostic trouble codes to be certain of the issue.
  5. Failed Emissions Test - A diagnostic check of the engine’s computer has to be done in some states in the U.S. In order to pass an emissions test. A trouble code will be stored in the car’s computer if the catalytic converter is faulty. If this error pops up, then the car will fail the test.

Which Tools Do I Need To Repair My Car Catalytic Converter?

There are several skilled auto mechanics who have a goal of opening their own car repair shop in their career. But let’s face it; if you want to put up an efficient and profit making shop, then you might need much more than mechanical skills. There are several tools which you might need to perform the car repairs quickly as well as reliably. Auto repair equipment that you will need to repair your Catalytic Converter may include:

Which Top Brands Catalytic Converter Parts Should I Choose?

For vehicle owner’s choice, the brands really matter a lot. You might pay a premium for a specific car part brand, over time, as it has created a perception of quality, stability and trust. There are some leading car parts brands which are more than just products or services as they give rise to memories and emotions related to with the quality. So have a look at some of the top brands for Catalytic Converter:

  • Walker Converter
  • Magnaflow Converter
  • Bosal Converter
  • Dorman (Oe Solutions) Converter
  • Flowmaster Converter
  • ATP Professional Auto Parts Converter
  • Blue Streak (Hygrade Motor) Converter

For more information about Top Brand Catalytic Converter, visit our Which Popular Brand Of Catalytic Converter Should I Choose? Section. 

Which Parts Are Related To My Car Catalytic Converter?

If you are like most of us, then you won’t know much about the related components of car Catalytic Converter. Fear not! Here is a quick and easy guide to explain the related parts of the Catalytic Converter:

  • Exhaust Manifold and Converter Assembly
  • Converter Control Relay
  • Catalytic Converter Air Tube Kits
  • Catalytic Converter Connector
  • Muffler
  • Header
  • Manifold

What Are The Steps Of Changing My Car Catalytic Converter?

A catalytic converter is perfectly designed to lessen the pollutants which are emitted from a car's exhaust system. As time goes by, you will have to replace your catalytic converter. If you have the mechanical skills and the ability to read through your car's manual, then this can be easily done. In order to complete the replacement, you can follow the directions below.

Step 1 - Elevate the Car

By using a pair of ramps or car jack, you must raise the car in the air. By doing this, you will have plenty of room to work around or inside the car without any obstacles in your way.

Step 2 - Consult the User Manual

Look for your car’s manual. Look for the information specific to the catalytic converter. Have a look at all the diagrams available and make sure that you know what you are looking at when you dismantle the catalytic converter and replacing it with a new one. Be careful of the small parts, pieces and the bolts which holds all the components in place. If you are not sure, take the help of an automotive mechanic.

Step 3 - Remove the Bolts

Look for the bolts which holds the catalytic converter in place and obliterate them. It might not be easier to remove the bolts as they can give resistance. They may also be corroded. In order to remove the bolts safely, use a drill or a saw. Along with the bolts, remove the nuts and the seals.

Step 4 - Purchase a new Catalytic Converter

Get a new catalytic converter and make sure it is particularly designed for your vehicle. Never buy a rebuilt part which is not designed for your vehicle as it will be more difficult to drive and you will have to replace them again.

Step 5 - Remove the O2 Sensor

With the help of an O2 wrench, carefully remove the O2 sensor. Apart from this, you will have to remove the pipe which connects the sensor to the catalytic converter. Check your manual again. You will have to remove more than 1 pipe in a few cars. This action has to be done before you unbolt the catalytic converter from the muffler. Now take away the old catalytic converter and place on a piece of cardboard or location which is guarding the ground or the surface.

Step 6 - Replace Old with New

Fix the new catalytic converter into place and bolt them in the right position. The pipes have to be reattached (in the exhaust system and the O2 sensor). If the pipe has been cracked or rusted over the course of your installation, replace them.

If you want to know exactly when you should change your catalytic converter, then you should surely visit our When Should I Change My Catalytic Converter section. 

If you are still confused about which type of car Catalytic Converter you should buy, then you can visit our The Ultimate Catalytic Converter Buying Guide. You should always look for the warning signs of a bad Catalytic Converter and replace them at the earliest you can. With us, you can find Catalytic Converter at the most economical cost