Will Catalytic Converter Stop Car From Running?

Will Catalytic Converter Stop Car From Running

Catalytic converters are an important part of a car’s emission system and are capable of lasting as long as a car does. However, there have been different improvements in catalytic converters over time but irrespective of that, they still fail.

Therefore, the question is, will catalytic converter stop car from running?

A catalytic converter will stop a car from running if it is totally plugged in. A bad catalytic converter will not necessarily stop a car from running, in fact, it is not considered dangerous, but needs to be replaced as soon as possible.

Whether the catalytic converter stops the car from running or not, once you start seeing symptoms that it is failing you should take steps to replace or fix it.

Will Catalytic Converter Stop Car from Running?

In order to determine if a catalytic converter will stop a car from running, we need to first understand what a catalytic converter is and how it works in a car.

Catalytic converters are usually made up of precious metals such as; rhodium, platinum, and palladium. It works in a car by changing harmful substances like nitric oxide, hydrocarbons, etc., in a car’s exhaust gas into less harmful substances like water vapor and carbon dioxide through chemical reactions.

Will a catalytic converter stop a car from running? Yes, a catalytic converter can stop a car from running. Driving a car with a bad catalytic converter in itself will not stop the car from running, however, if it is fully plugged in, it will stop a car from running.

If the bad catalytic converter is partially plugged in, the car can still be driven normally but with a drop in its performance. The same cannot be said for a fully plugged-in catalytic converter when bad, it will stop a car from running.

What Can make Catalytic Converter Stop Car from Running?

It has been established that a catalytic converter can stop a car from running but what exactly is it that causes that to happen? A clogged or faulty/bad catalytic converter may stop a car from running depending on how it is plugged.

Here are some problems that indirectly cause a catalytic converter failure and can stop a car from running;

  • Antifreeze Enters the Exhaust System: Antifreeze in the exhaust system will create thick carbon and soot that eventually clogs the air passage. A clogged catalytic converter will not do its work optimally and may eventually stop a car from running among other things.
  • Damage Done by the Road: Cars are meant to be driven on the road but this doesn’t mean the road can’t do some damage to the car. The catalytic converter has a catalyst honeycomb inside that is made up of lightweight and fragile ceramic material. The driving condition of a car over time can cause the catalytic honeycomb to be fractured, once it is broken, there is an obstruction of the flow of exhaust. This damage will require that the catalytic converter be changed.
  • Bad Spark Plug: A bad spark plug will not fire or misfire, when this happens unburned fuel is allowed inside the exhaust system. Unburned fuel can ignite inside the converter as a result of the converter’s hotness.

What to Do if Catalytic Converter Stops the Car from Running?

For a catalytic converter to stop a car from running then it is most likely clogged or faulty. What can be done when this happens?

  • Troubleshoot the Problem: You will have to first determine the true cause of the problem, whether it is a result of a clogged catalytic converter or a bad one. This should be done by a mechanic in order to prevent further damage from being done.
  • Clean Out the Clogged Catalytic Converter: This can be done by pouring a cleaning solution inside the gas tank, there are suitable over-the-counter cleaners that can be used. In some cases, a deep cleaning of the catalytic converter may be needed. It is important to note that cleaning a catalytic converter is not recommended by manufacturers.
  • Replace the Catalytic Converter: Rather than clean the catalytic converter, a more suitable option is to replace the catalytic converter. To do this, you should employ the services of auto experts.

5 Key Symptoms of a Failing Catalytic Converter

It is not uncommon for a catalytic converter to last throughout the lifetime of a car but over time it can go bad. This tends to happen when the catalytic converter gets clogged which often happens in older cars. It is quite easy to detect symptoms of a failing catalytic converter.

Here are some symptoms you may want to look out for:

1. Check Engine Light is On

This is a common symptom when some parts of the engine system are not functional and is also applicable to a failing catalytic converter.

A car’s onboard diagnostic system is able to pick up when too much pollution is coming out of the tailpipe and it in turn makes the check engine light come on.

When the check engine light is on, it is always an indicator that something is wrong somewhere in the car that needs checking out.

2. Reduction in Fuel Efficiency

Different vehicles have different gas mileage depending on the engine size. There may be a reduction in a vehicle’s gas mileage if the catalytic converter is failing.

The engine has to work harder than it usually does because it is not getting enough oxygen, this in turn causes it to consume more fuel than usual.

3. Reduction in Engine Performance

Although a reduction in engine power and performance can be attributed to other engine issue, it may also be a sign that there’s something wrong with the catalytic converter. A catalytic converter blocked by exhaust will not allow the engine to run well.

4. No Start or Stalling of the Car

A clogged or faulty catalytic converter may cause no start or stalling of the car. A clogged catalytic converter will prevent exhaust from going out through the back of the car, increased exhaust pressure will cause the engine to stall, and it may even run for a few minutes before stopping altogether.

5. Failed Emission Test

Depending on the state of residence, it is part of a car’s routine for the emission to be checked in order to be sure it is in good condition. If there is an increase in the level of carbon emitted from the exhaust then the catalytic converter may be going bad.


When a car stops running, it can be attributed to various internal problems, a failing catalytic converter inclusive. The replacement of a bad catalytic converter should be done by an auto expert and in time. A delay in replacement could cause further damage to the engine including engine failure.