Does it Harm an Engine to Drive with Bad Catalytic Converters?

A catalytic converter is a vital organ in a vehicle’s exhaust structure. This catalytic converter is located between the engine and the muffler in the car exhauster.

Its purpose is to reduce air pollution from gases that come out of the exhaust system as a result of incomplete combustion of fuel. The gases produced are hydrogen oxides and carbon monoxide, and they are a threat to human life.

The catalytic converter through reduction and oxidation processes turns these gases into less harmful compounds i.e., carbon dioxide (though it is said increased carbon dioxide is a primary cause of global warming) and nitrogen (a naturally existing gas in the air.

The processes taking place inside the converter are made possible by catalysts made from precious metals. These catalysts speed up the reduction and oxidation processes without been changed. This tells you how important catalytic converters are.

Does it Harm an Engine to Drive with Bad Catalytic Converters

When a catalytic converter fails, it exposes humanity to danger, even the environment around us. Therefore, when you drive with a broken catalytic converter, you contribute to making the environment unsafe and exposing yourself and your passengers to health problems.

Even though you can still move around with your car even when its catalytic converter is not properly functioning, your car will have a foul smell and will produce smoke when riding.

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The vehicle will only function less efficiently even though it will not stop running even with a broken catalytic converter. But a broken catalytic converter can make you not drive your car when the police catch you.

Because polluting the environment is a break of law in many countries. When that happens, you will part with some amount of money because you will pay fines.

Also, you may not drive the car again until you install a new catalytic converter. Still, the catalytic converter can make it impossible to ride your vehicle, which is in the worst-case scenario when it is completely blocked. And this will take place if you go on driving your car with a broken catalytic converter.

Signs and Symptoms of a Bad Catalytic Converter

To ride with bad catalytic converters and taking precautions, you will have to be sure the cat con of your car is bad. The engine will give you are the signs of a bad cat con, and this section discusses some of these signs so you can be on the lookout.

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Reduced Engine Performance

If you notice reduced engine performance, the catalytic converter may be failing. This performance issue becomes worse with time. The responsiveness of the engine reduces, and it takes time to start. Immediately you step on the accelerator the car accelerates after minutes.

Abnormal Noises

You are out for a drive, and the car starts to pronounce uncommon noise, especially from around the engine area. This is an indication that the cat con is going bad. Brocken pieces inside the catalytic converter produce that sound.

In that event, action is urgently required because the broken pieces can block the exhauster forcing the wheels to stop. Broken pieces in a cat con are a serious issue.

Rotten Egg Smell

It is easy to identify this sign. In normal situations, a cat con breaks down harmful smelly gases to odorless substances. When the cat con is bad, it does not function properly, and that is where the smell of rotten eggs comes from. The main element causing the rotten egg smell is sulfur.

Conducting an Emission Test

You can contact a professional to test emissions from your car to be certain the cat con is failing. The specialists can also advise you on what to do.

Riding with Bad Catalytic Converters

As earlier mentioned, you can ride your vehicle even when the cat con is bad. But having a correctly working catalytic converter is good for the following reasons:

  1. Efficiency in the performance of your car
  2. Environment conservation

You can avoid repairing a broken cat con if you decide, but the answer to whether a car having a bad cat con can be driven is yes. First cars to be manufactured did not have catalytic converters. Therefore, if your car is among the first-generation vehicles, it does not have a cat con.

Does it Harm an Engine to Drive with Bad Catalytic Converters

Effects of a Bad Cat Con to the Engine

If the cat con is slightly broken, it does not harm the engine so much, although this depends on how careful you are when driving. If the distance you cover when driving, e.g., to the workplace, is shorter, the broken cat con will not severely damage the engine, and you do not even need to replace it immediately.

However, if your vehicle covers many kilometers frequently, having a bad catalytic converter will damage your engine, and it will automatically fail.

But remember that even if the cat con is slightly broken, fuel costs will increase because the car uses extra oil. You will also not expect the engine to perform perfectly; there will be slight changes. But, when the cat con is severely damaged, it can extensively harm the engine in the following ways:

Low Engine Performance

Bad cat cons make your car engine performance drop. Note that the cat con is part of a car’s exhaust structure, directly connected to the engine. When it fails, the engine fails. If the cat con is blocked, it does not allow all the exhaust gases to move out, and if it is broken, it makes fuel leak, reducing the engine’s performance.

Also read: How to Clean a Catalytic Converter


Bad cat cons cause misfiring. Misfiring happens when gas gets heated up until it ignites. This misfiring takes place inside the engine and can damage engine components.

The Engine Becomes Too Hot.

Damaged or broken cat cons make the engine to heat up abnormally. Particularly if you have been driving long distances, the area around the engine gets so hot it can burn you. This scenario can ignite the whole vehicle in the slightest chances possible. If you engine already became too hot, look for symptoms of a cracked engine.

Considerations to Make When Driving with Bad Cat Con

While it is advisable to replace your cat con when it starts failing, sometimes that may not happen as soon as it should, and you still want to move around with your car. Therefore, it is necessary to take the following precautions to ensure your safety and the safety of your car:

Driving a vehicle with a bad catalytic converter can make the vehicle very hot. You need to consider that and plan to ensure the heat up is not too much if you decide to ride with broken cat cons.

There is also a small possibility of the car catching fire because of the heat. However, this may only happen when driving long distances. Be prepared to stop on the way for the car to cool down so that you do not get into more trouble

You may end up stopping several times to refuel the car. Bad cat cons make the engine burn more fuel than normal situations. Therefore, if you are going for a long drive, carry some extra cash, so you do not get stuck on the road. It might be inconveniencing, but these are some of the disadvantages of driving with a bad cat con. Avoid roads with few filling stations, so you do not get stranded in the middle of nowhere.

Before you hit the road, find out if it is illegal to use the road you intend to with a bad cat con to avoid trouble with the police. In case you are caught, you may end up not reaching your destination and paying fines.

Rather than been fined, it is better to replace the cat con because it is cheaper than been fined. Moreover, even when you are fined, you will still not drive the car until you replace the cat con, which is double expenditure.

The last point you need to consider is that you may end up causing a complete breakdown of the cat con. While this is not your intension, the excessive heating up can make the cat con worse because it burns the inner fiber of the cat con.

Although this will not bar your car from moving, the amount of smoke your car will produce is worrisome if you care about the environment.

The first catalytic converters were not so effective in their work. However, with improved technology, recently produced cat cons are highly effective and reliable. They last long because they are made of metals that do not wear out easily.

But remember with machines anything can happen and the next thing you know is it’s a failure. So, just like all other machines, catalytic converters can fail.

Note: Never trade regular car maintenance with money. If you do not take that car for regular maintenance, you may be feeding your car trouble and waiting for it to show signs. When you take the car to the mechanic often, minor problems are detected early and fixed.

From the above discussion, you know what a catalytic converter is, the effects it has on the engine, how to identify a cat con that is failing, and how to prepare yourself if you decide to drive with the bad at the con. Note that it is not advisable to ride around with a broken cat con.

But not all situations involving cat cons need you to look for a replacement. Sometimes the cat con is just dirty and only needs cleaning. Other times, you may be the type who drives short distances.

In that case, you do not need to replace the gadget as soon as it develops problems even though the car will emit some pollutants into the air.

Replacing catalytic converter may not necessarily mean you are going to buy the cat con, you may have to replace other parts of the exhaust system.

Therefore, it is good to have a specialist advise you on what to do. In cases where the damage is extreme, then you will hand over the work to the specialist.

Whether you move with a bad cat con or not ensure it is fixed as soon as possible. Always make sure you grab a repair manual before you repair any part of a car. You may need to confirm one or two things.

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