Catalytic converter rattle symptoms and solutions

Your car might deteriorate with time, and your converter might produce rattling sounds after driving for about 100,000 miles. Although you can clean the converter to reduce the rattling, sometimes the issue might be persistent.

Do you know the catalytic converter rattle symptoms you should look for and how to fix them? Read to learn how to fix your rattling converter.

Can a bad catalytic converter cause a rattle?

A catalytic converter should last for a long time, but overly rich fuel mixtures might damage it. The converter might develop clogs, and some sections might collapse.

The dirt in the catalytic converter might prevent it from functioning optimally, causing noises. You may hear ticking noise caused by oil, fuel, and coolant burning; the ticking noise occurs in a cold startup, during acceleration, idling, and leakage in the converter.

You may hear a pinging sound which indicates clogs from overheating, age and fuel contamination. On the other hand, a knocking noise occurs due to a loose heat shield and leakage, while a popping noise indicates a restricted exhaust flow resulting in backpressure.

The rattling from below the feet occurs when the converter has been idle or if the honeycomb has failed. The noise may occur for a few minutes and stop as you apply the gas when starting your car. On the other hand, the noise which persists with acceleration occurs if the ceramic honeycomb is broken.

What Consequences Does A Rattling Catalytic Converter Cause To A Car?

The rattling catalytic converter indicates serious issues with your car, and if you don’t deal with the issue, it might damage your catalytic converter. For instance, the noises may occur due to blockage, leakage, and exhaust obstruction.

Since the catalytic converter cleans the exhaust from your vehicle, blockage leads to pressure build-up, which collapses the catalytic converter.

Moreover, it makes it impossible to clean the exhaust fumes from the car. Therefore, you should ensure the catalytic converter is in good condition to avoid releasing toxic chemicals.

You may face serious legislative consequences if you release the toxic gases into the environment, and it may be wise to ensure your catalytic converter is in good condition.

Is It Worth Fixing A Catalytic Converter Rattle?

It is worth fixing a rattling converter since you will be avoiding issues with the converter itself. First, the rattling noises might occur due to broken parts, and without fixing the broken parts on time, you will need to replace the whole converter.

Furthermore, the noises might indicate issues such as blockage, which damages the converter and impacts its ability to filter the air.

Moreover, the rattling sounds might indicate issues with the gas mixture in the engine. If your car does not have the right fuel, it may result in a rattling converter.

How Do You Fix A Rattle In A Catalytic Converter?

1. Cleaning the catalytic converter

Dirt might be why your catalytic converter is rattling; thus, you should clean it, especially if you have not cleaned it in a long time. The dirt might block the airways resulting in noise and poor catalytic converter performance.

Your catalytic converter might have a rotten egg smell if it is blocked by debris as it would not convert hydrogen sulfide to sulfur dioxide. You may need to take out the catalytic converter before cleaning it for efficient cleanliness.

2. Clean with sodium peroxide

Sodium peroxide will clean the catalytic converter, getting rid of the dirt in the catalytic converter as it gets rid of the hydrogen sulfide.

You can pour the cleaning sodium peroxide solution into a spray bottle and spray both sides of the catalytic converter over a drip bucket.

Let the solution soak for 30 mins, and clean the inside and outside of the converter with water connected to the nose. Ensure rhea water is clear before reinstalling the converter back.

4. Use a lacquer thinner

The lacquer thinner can increase engine performance and fuel efficiency; you can add one gallon of the lacquer thinner into an empty gas tank and add about 10 gallons of gas.

Then drive for about three hours at 2500 RPM for at least a third of the trip. The lacquer thinner which flows through the system will cleanse any blockages in the catalytic converter.

5. Fix the heat shield

The heat shield might be why your catalytic converter is producing noises, and any blockage increases internal temperature. Thus you should check for loose bolts as they would cause rattling noises in the catalytic converter.

Penetrating oil might make it easy to remove any lost bolts, and you can replace all bolts to ensure the heat shield is properly secured on the catalytic converter.

6. Use high-quality fuel

Good quality fuel might resolve any issues with the catalytic converter. You can switch the low-octane gas to high-octane and have it run through the vehicle.

High-quality gas breaks down easily and does not leave toxins that are difficult to clean. High-octane gas might clear up the airflow and stop catalytic converter rattling. You may add additives to the tank, which cleans up the whole system.

7. Replace the catalytic converter

Although replacing the catalytic converter might be the last option, it might reduce rattling and promote better exhaust gas cleaning.

You should ensure the replacement part fits your car model; thus, buying from trusted vendors or content the company support services is better.

Ensure the catalytic converter is well fitted into the car to avoid future problems and use the right fuel, which does not cause blockage.

What Does A Failing Catalytic Converter Sound Like?

A failing catalytic converter might produce pinging, knocking, popping, ticking, and rattling noises. The noises indicate blockage within the system, poor performance, and an inability to clean the toxins from your exhaust system.


Your car catalytic converter might develop rattling sounds due to blockage, poor performance, and an inability to clean the exhaust fumes.

The blockage makes it challenging to clean the gas released from combustion leading to a rotten egg smell. You may clean the catalytic converter to remove debris blocking the airways, use the right fuel that burns easily, and replace the whole unit.

It is important to address the rattling noise before the whole catalytic converter is damaged; moreover, you can meet clean exhaust regulations with an effective catalytic converter.

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