How to Unclog Catalytic Converter? (4 Methods)

You’re reading this because you want to know how to unclog a catalytic converter. If you operate a car with an internal combustion engine, you should expect to encounter a blocked catalytic converter. Why is this the case?

A blocked catalytic converter may cause a nauseating smell of rotten eggs, a very hot underbelly, low fuel mileage, a reluctant and stuttering start, and poor acceleration.

The final symptom is a failed emission check, thus cleaning it should be a top priority in car maintenance.

To unclog, use the Italian tune-up technique or fuel additives with the Italian tune-up method to achieve the best results. You can also remove the catalytic converter and clean it by following a simple process.

Did you know that the most number of vehicle parts stolen cases is directly related to the Catalytic converters do you want to know to prevent this from happening to your vehicle? a complete guide for you to protect and prevent from happening.

What’s a Catalytic Converter?

A catalytic converter is a device that converts hazardous engine exhaust into innocuous gases. This conversion is accomplished by the employment of a catalyst, which is a chemical that aids in the acceleration of the reaction without being consumed in the process.

In many countries, catalytic converters are needed by law to limit the amount of pollution released by cars.

Catalytic converters are fitted in a vehicle’s exhaust system between the engine and the muffler. They are typically attached to the exhaust pipe through a flange connection. A honeycomb-shaped structure is covered with catalyst material in the converter.

The catalytic material triggers a chemical process that breaks down exhaust gases as they pass through the converter.

The catalytic material in the converter produces a chemical process that breaks down hazardous pollutants into innocuous gases before they are discharged into the atmosphere when exhaust gases pass through it.

Do All Vehicles Have A Catalytic Converter?

No, not all automobiles are equipped with a catalytic converter. Some older vehicles do not have one, while some modern vehicles are not built to have one. These vehicles often employ alternative technology to assist reduce dangerous pollutant emissions.

Symptoms of a Clogged Catalytic Converter?

How to Unclog Catalytic Converter? (4 Methods)

Driving a car with a blocked catalytic converter can be incredibly painful. Aside from the environmental concerns, you risk ruining your car’s engine. Fortunately, several indications appear when a car’s catalytic converter is blocked. They are as follows:

  • Engine Performance Issues: The engine is slow to accelerate or difficult to start. If you notice these symptoms, it is likely that your catalytic converter is clogged. Clogs are impeding the passage of exhaust from the engine. When a catalytic converter becomes clogged, it impacts the engine, stopping it from expelling pollutants into the atmosphere.
  • Fuel Efficiency Issues: Exhaust gases trapped within the engine reduce the quantity of air and oxygen that enters the engine. When this happens, even with your foot on the gas pedal, the vehicle engine struggles to accelerate. As a result of having to work harder, your vehicle engine uses more gasoline.
  • Failed Vehicle Emission Tests: After noticing the check light on, the next obvious step is to do a car emission test, as nothing indicates a blocked catalytic converter more than a failed vehicle emission test.
  • The smell of Rotten Eggs: When your catalytic converter becomes blocked, you might smell Sulphur. That gas is known as “rotten egg” gas. It is caused by the development of Sulphur dioxide (H2S). When a catalytic converter fails to function effectively, it is unable to remove impurities and may emit this gas. Furthermore, ammonia (NH3) odor is an indication of inadequate catalyst activity.
  • Unpleasant Noise: Noise is a red flag. If you hear noise upon starting the engine, it is likely due to a faulty catalyst.
  • Warning Sign: Check the car warning lights to see whether the problem is with the catalytic converter. You examine the check engine light or malfunction indication lamp (CEL or MIL) to see whether it displays a catalytic converter diagnostic issue code (DTC).

To figure out the cause of a Clogged Catalytic Converter

Here are several methods for diagnosing a blocked catalytic converter.

1. Back Pressure Test

This test requires a back pressure gauge and takes place in the exhaust system.

  • Take off the front oxygen sensors.
  • It should be replaced with a backpressure gauge.
  • Then you start the car engine and pay attention to the pressure gauge reading. Anything between 0 and 3 psi is common, especially when the RPM is increased to roughly 2500 rpm. A measurement of 8 psi or higher indicates that your car’s catalytic converter is blocked.

2. Vacuum Test

To conduct this test, you will need a vacuum gauge and some help (optional).

  • Depending on the kind of vehicle, you should set the transmission to park or neutral before using the parking brake.
  • The vacuum gauge is then connected to a direct vacuum line, similar to a direct intake manifold port.
  • Start the engine and let it idle until it reaches operating temperature. At this stage, the vacuum gauge should be between 18 and 22 in-Hg.
  • Maintain a speed of 2500-3000rpm while keeping an eye on the suction indicator. Its reading should decline for a few seconds before returning to its previous level. If it takes an eternity for the reading to recover to its previous level, you most likely have a clogged catalytic converter.

3. Temperature Test

  1. Start the car and allow it to reach operating temperature (you could take it for a short drive or just let it idle for some 20 minutes).
  2. Make sure it’s on a level surface.
  3. Set your transmission to “Park” or “Neutral” depending on your vehicle.
  4. Take a temperature reading from the input pipe that attaches to the front of the catalytic converter and write it down. You may need to lift your vehicle to do this.
  5. Rep for the output pipe that links to the catalytic converters back. If the front and rear temperatures are at least equal, there is a problem with the catalytic converter.

So How to Unclog Catalytic Converter? 3 Methods

You’re certain about the condition of your catalytic converter at this point, and you’re probably seeking a speedy remedy. The good news is that you can unclog your catalytic converter in three methods. However, there are a few things you should keep in mind.

To Unclog Catalytic Converter without removing it.

Method -1

Italian Tune-Up

This strategy is simply slanged for driving at high speeds in order to generate enough heat and air to burn off the deposits that are blocking up your catalytic converter.

There are various approaches to this. In a manual transmission car, change between second and third gear, wait for the vehicle to reach the redline, and then shift.

For automatics, you should run a vehicle harder for several miles. The high temperature will burn off performance-robbing deposits in the cylinder head, oxygen sensors, intake, exhaust, and catalytic converter.

You don’t want to get a speeding ticket or risk yourself and other drivers just to clean your converter.

This strategy is frequently effective—despite the critics, it is often preferable to listen to genuine mechanics and experienced individuals.

Method – 2

Use Fuel Additives  

The only method to get chemicals into your car’s system to clean the catalytic converter is through the gas tank.

Oil, like water, degrades and burns off, leaving a remnant (in the form of sludge and deposits) that enters the cat converter.

Oil additives are also helpful in removing the “oil poisons” that clog up and lower the performance of a catalytic converter.

  • Duralube Catalytic Converter Cleaner: Improves combustion efficiency by eliminating or decreasing oil toxins in the system.
  • Catalytic and Exhaust Treatment with Duralube Severe: The same as above, but with a stronger composition

When paired with efficient fuel additives, a badly blocked catalytic converter has a good chance of being rescued.

This procedure is also excellent for cleaning your exhaust, fuel, and oxygen sensors.

Here’s how you do it:

  1. Purchase a catalytic converter cleaner that is compatible with your vehicle.
  2. Make sure you have at least 15 liters of petrol in your tank.
  3. Follow the directions for using catalytic converter cleaner in terms of the fuel/catalytic converter cleaner ratio.
  4. Fill the gasoline tank with catalytic converter cleaning.
  5. For roughly 30 minutes, drive your automobile at 2500rpm (or more). The goal is to drive long enough for the catalytic converter/fuel combination to circulate throughout the vehicle and clean the system. However, ensure sure the automobile does not overheat throughout this journey.
  6. Re-calibrate the OBD code, then re-read the catalytic converter.

When you refuel, consider adding one gallon of lacquer thinner to ten gallons of petrol. This may aid in the removal of solids accumulated in the catalytic converter. It’s a good idea to combine this procedure with the “Italian Tune-Up” method.

To Unclog the Catalytic Converter by removing it.

Method – 3

DIY Clean a Converter

Another option is to clean the converter on your own. This is the ideal option if you have prior experience with vehicle maintenance and the appropriate tools.

The following are the tools you will require:

  • Some degreaser for vehicles
  • Some penetrating oil
  • A jack for the floor
  • An impact wrench is held by Jack.
  • A high-pressure washer
  • Allow the exhaust system to cool to avoid being burned.
  • Jack up the automobile and suspend it using jack stands.
  • Remove the oxygen sensor (s)
  • To loosen the bolts, use penetrating oil.
  • After removing the catalytic converter, inspect it. If you hear a loud rattling, you should pull over since the catalytic converter components are most likely broken. If you do not hear anything, you should proceed with the process.
  • Wash the catalytic converter using a low-pressure pressure washer.
  • Place the catalytic converter in a bath of hot water and degreaser.
  • Rinse the catalytic converter using a low-pressure pressure washer.
  • After allowing the catalytic converter to drain and dry, reinstall it.
  • Reinstall the oxygen sensor(s) after the catalytic converter is back in its place.

Method – 4

Get Professional Assistance

Another solution is to remove the converter and get it cleaned by a professional. If the converter is severely blocked, this is typically the best solution.

How to Extend the Life of Your Catalytic Converter?

Keeping your fuel and oil systems clear of deposits, contaminants, and sludge will increase the dependability and durability of your vehicle.

Here is how:

  • Drive your car frequently: The machine needs to be used
  • Timely Oil Change: Oil changes performed on a regular basis are equally as useful as any oil or gasoline additive in functioning as a preventative maintenance tool.
  • Consider using to high-octane fuel: Premium and Plus Fuels are also excellent preventative maintenance techniques
  • Regularly scheduled maintenance: Regular service from expert technicians knows well what to do to prevent clogging catalytic converter by servicing, washing from chemicals, cleaning and etc.


Frequently Asked Questions:

Can I use a hammer to hit my catalytic converter?

Yes, Strike the pipe with the hammer. This will clear any junk that has accumulated in the converter.

Finally, knock on the top of the converter with the hammer to remove any debris that may be caught within. Reattach the catalytic converter to the vehicle and tighten the bolts. It’s as simple as that!

Note: If you hit the catalytic converter with a hammer and hear a rattling sound, the substrate has crumbled and the catalytic converter should be replaced rather than unclogged.

Can seafoam clean a catalytic converter?

They are not the same in that they do not immediately clean a cat converter but rather prevent your system from accumulating deposits that will block it.

What is the most effective catalytic converter cleaner?

What are the 3 most leading failures of a catalytic converter?

  • Overheated
  • Melted
  • Broken converters

About The Author

Avatar for Ibrar Ayyub

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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