A catalytic converter is an important part of your car’s exhaust system. It helps reduce harmful emissions and keeps the environment cleaner.
Over time, however, it can get clogged or dirty, which can affect your car’s performance and fuel efficiency.
Cleaning your catalytic converter can save you money on repairs and even help your car run more smoothly.
The good news is that cleaning it doesn’t have to be complicated! In this guide, we’ll walk you through simple steps to clean your catalytic converter safely and effectively.
Whether you’re a car enthusiast or just want to keep your vehicle in top shape, this easy-to-follow process will help you get the job done.
No special tools or advanced knowledge is needed, just a little time and effort! Let’s get started and bring your catalytic converter back to its best condition.
What is a Catalytic Converter and Why does it Clogs?
A catalytic converter is an essential part of a car’s exhaust system. Its main job is to reduce harmful emissions by converting toxic gases from the engine into less harmful substances before they are released into the air.
This happens through two chemical processes: oxidation and reduction. Oxidation adds oxygen to harmful gases like carbon monoxide, turning it into carbon dioxide.
Reduction, on the other hand, removes oxygen from nitrogen oxides, breaking them down into harmless nitrogen and oxygen.
These processes take place inside the converter, which contains a honeycomb structure coated with metals like platinum, palladium, or rhodium that act as catalysts to speed up the reactions.
Over time, a catalytic converter can become clogged. This usually happens when unburned particles, such as oil or fuel, build up inside it.
Common causes include using contaminated fuel, engine oil leaks, or worn-out spark plugs that don’t burn fuel completely. Excessive engine wear can also send more harmful particles into the exhaust, creating blockages.
Additionally, short trips or frequent stop-and-go driving can prevent the converter from reaching the high temperatures needed to burn off contaminants.
Once clogged, the converter can restrict exhaust flow, leading to reduced engine performance.
Why do we need catalytic converters?
The short answer is that catalytic converters offer an effective method of removing harmful waste products that result from the combustion of automotive fuels.
Such as various compounds of nitrogen and oxygen, commonly known as NOx, from automotive exhaust gas.
As a practical matter, “NOx” is a generic term that describes a wide range of oxygen/nitrogen compounds, with the exact composition of each specific compound depending on, among other things-
- the type and quality of fuel used.
- the quality of the oil in the engine.
- the engine speed and load at the time a specific volume of NOX was created.
- the mechanical condition of the engine.
Limited space precludes a comprehensive discussion of the role each of the listed conditions plays in the formation of NOx, but suffice it to say that-
- all modern internal combustion engines can potentially generate NOX under some operating conditions.
- all modern engines are fitted with one or more systems that reduce the formation of NOx but at the same time, no mitigating system can completely eliminate the formation of NOx under all operating conditions.
What Does the Catalytic Converter Do?
A catalytic converter reduces the emissions from the engine’s exhaust by means of a chemical reaction. If you split the assembly in half, you’ll have two primary sections.
Most vehicles have two converters – one near the engine (the light-off cat that handles NOx). This one is monitored for efficiency by a downstream O2 sensor.
The cat that handles the HC and CO is the rearmost cat (usually a separate unit from the front one on newer cars) and is not monitored by a downstream O2.
The first one is a catalyst with a combination of platinum and rhodium. It works by breaking down oxides of nitrogen (NOx) into nitrogen and oxygen molecules.
As the exhaust gas travels further, it passes through a second catalyst, which is a combination of platinum and palladium.
Here is where two-way oxidation takes place—carbon monoxide (CO) and hydrocarbons (HC) are broken down into less harmful molecules such as carbon dioxide (CO2) and water (H2O).
A properly balanced fuel mix will produce mostly CO2 and water. A slightly rich mixture will produce CO (not enough O2 to go around) and a leaking injector or VERY rich mixture will produce high HC (hydrocarbon – unburned fuel) in the exhaust, which shows up as soot.
NOx is produced when combustion chamber temperatures exceed 2500 degrees, because most of the atmosphere in the mix (78%) is nitrogen, which is superheated by the combustion event to drive the piston down.
Above 2500 degrees, nitrogen molecules bond to O2 molecules in various different compounds – that’s why it’s referred to as NOx (x can be any one of several different numbers).
The oxygen (O2) molecules from the first catalytic conversion bond with CO molecules and form CO2. The hydrogen and carbon molecules from the hydrocarbon compound split to bond with oxygen and form CO2 and H2O.
After the whole process, the now-less-harmful exhaust gas travels until it reaches the end of the tailpipe, where it’s dispersed into the atmosphere.
For your car to pass the emissions test, the catalytic converter should be in optimal condition.
What Causes a Clogged Catalytic Converter?
All catalytic converters may clog up over time.
However, there are a few additional factors that can hasten the process:
- Unburned fuel: Incomplete combustion leads to unburned fuel, which burns the catalytic converter. This results in a partial or complete meltdown and blockages.
- Leaking coolant: Engine coolant may leak into the exhaust system if the engine has faults. The coolant combines with carbon deposits in the cat converter and creates soot, which blocks the catalytic converter and restricts exhaust flow.
- Oil slipping into the exhaust system: Engine oil leakage can spill into your exhaust system. There, the oil combusts, releasing thick soot that clogs the catalytic converter.
- Damaged spark plug: A damaged spark plug fails to ignite the engine properly, which leads to excessive unburnt fuel in the exhaust system. The unburnt fuel accumulates anytime there’s an engine misfire, leading to clogging.
- Structural damage: A damaged catalytic converter may break into little pieces that clog the system.
What Are the Symptoms of a Clogged Catalytic Converter?
Driving a car with a clogged catalytic converter can be a pain in the butt. Besides the environmental pollution issues, you run the risk of damaging your car’s engine.
Thankfully, some symptoms pop up when a car has a clogged catalytic converter. Here they are:
#1. Reduced Engine Performance.
One of the first signs of a clogged catalytic converter is reduced engine performance. You may notice:
- Sluggish acceleration.
- Difficulty maintaining speed, especially uphill.
- A lack of power during normal driving conditions.
If your car’s engine feels like it’s struggling to breathe, it’s time to consider catalytic converter troubleshooting tips.
#2. Check Engine Light Is On.
When your catalytic converter is clogged, it often triggers the check engine light. Modern vehicles are equipped with sensors that detect when the converter isn’t working correctly.
A diagnostic scan can reveal trouble codes related to the catalytic converter, such as P0420 or P0430.
Pro Tip: At Dave’s American Discount Muffler, we offer expert diagnostic services to pinpoint the exact cause of the problem.
#3. Dark or Thick Exhaust Smoke.
A properly functioning catalytic converter cleans up exhaust gases. If it’s clogged, you might notice dark or thick smoke coming from the tailpipe.
This can be a sign that unburned fuel or pollutants are making their way into the exhaust stream.
#4. Rotten Egg Smell.
A clogged catalytic converter can produce a sulfur-like odor, often described as a “rotten egg” smell. This occurs when the converter fails to process hydrogen sulfide properly.
If you’re noticing this smell while driving in Somers, WI, it’s time to get your vehicle checked.
#5. Excessive Heat Under the Vehicle.
A clogged catalytic converter can cause excessive heat to build up under your car. This happens because the blockage prevents exhaust gases from flowing freely, creating backpressure and overheating the converter.
You may even notice heat radiating from the floor of your vehicle.
#6. Poor Fuel Efficiency.
When your catalytic converter is clogged, your engine works harder to compensate for restricted airflow, leading to poor fuel economy.
If you’re filling up more often than usual, it’s worth investigating whether a clogged catalytic converter is to blame.
#7. Rattling Noise from the Exhaust.
If you hear a rattling noise coming from your exhaust system, it could mean that the catalytic converter’s internal components have broken apart due to clogging.
This noise often gets louder as the problem worsens, making it a clear indicator that something is wrong.
How To Diagnose a Clogged Catalytic Converter
The best way to be sure that your car has a blocked catalytic converter is to diagnose the car based on the symptoms you notice.
Thankfully, you can get some of the diagnostic tools you need online or at offline stores. That said, here are ways that you can diagnose a clogged catalytic converter.
#1. The Vacuum Test.
To conduct this test, you will need a vacuum gauge and some help(optional). Here are the steps you should take to conduct this test:
- Depending on the type of car, you want to set the transmission to park or neutral, after which you apply the parking brake.
- You then associate the vacuum gauge with a direct vacuum line like a direct intake manifold port.
- Start the car and let it idle until it gets to its operating temperature. The vacuum gauge should be somewhere around 18 and 22 in-Hg at this point.
- Maintain a speed of about 2500-3000rpm while you watch the vacuum gauge. Its reading should drop for a bit before returning to its former level in a matter of seconds. If it takes forever for the reading to return to its former level, then it’s very likely that you have a blocked catalytic converter.
#2. The Back Pressure Test.
You will need a back pressure gauge for this test, and the site of the test is the exhaust system. Here is how you conduct this test:
- Remove the front oxygen sensors
- Replace it with the backpressure gauge
- You then start the car and pay attention to the reading from the pressure gauge. Anything between 0-3 psi is normal, especially when you increase the speed to around 2500 rpm. A reading that is about 8 psi or more means that your car has a clogged catalytic converter.
#3. The Temperature Test.
To run a temperature test on your car, you will need thermometers (infrared or kitchen). Here’s how to conduct the test.
- Start the car and let it get to operating temperature (you could take it for a short drive or just let it idle for some 20 minutes).
- Ensure that it is on a flat area,
- Depending on the type of car, set your transmission to “Park” or “Neutral.”
- Get and note the temperature reading of the inlet pipe that connects to the front of the catalytic converter. You might have to raise your car to do this.
- Repeat the same for the outlet pipe which connects to the rear of the catalytic converter. If the front temperature is at least the same as the rear temperature, then there is some issue with the catalytic converter.
Considerations To Take Before Unclogging
There are certain things that you need to have in your mind before going on with the process of unclogging your catalytic converter.
There are certain situations when it is useless to try and clean your cat-con as it has already gone past cleaning, and the only way left now is to go for a replacement.
Hence it’s better taking a look at these points to keep your tiring efforts or cleaning going to total waste.
(a). Too Clogged.
In some cases, the catalytic converter is clogged up to a point where it does not even let the engine run. If this is the case, the specialist mechanic’s help should be sought or the cat-con be replaced altogether.
(b). Check If The Catalytic Converter Is Broken.
Try hitting the cat-con with a heavy thing such as a hammer; a noise would imply a broken part if it. Such a situation cannot be repaired; hence, it should immediately be taken to a workshop and be replaced without wasting your time.
(c). Fuel Combustion.
Sometimes, there could be a fuel leak, causing it to enter the cylinders and getting burned inside the catalytic converter.
If this is why your catalytic converter got clogged up then even if you apply the following methods, the situation will get back to this form within a short time requiring you to unclog soon again. So, it should be taken care of as well to avoid the clogging up again.
How to Unclog a Catalytic Converter
At this point, you are sure about the state of your catalytic converter, and you are probably looking for a quick fix for the catalytic converter.
The good news is that there are two ways for you to unclog your catalytic converter. However, here are some things you need to bear in mind.
It would be best if you ascertained that the catalytic converter is not clogged beyond repair. You also want to be sure that it is not broken.
If your catalytic converter is in any of these states, then you might want to get a mechanic’s help because applying a DIY approach might be futile. Once you have cleared that, you can opt for any of these methods of unclogging your catalytic converter.
Unclogging the Catalytic Converter without Removing It
There is a caveat for this method. It only works when the catalytic converter is not seriously clogged. You will need a catalytic converter cleaner.
This method is also great for cleaning your exhaust and fuel systems as well as your oxygen sensors. Here’s how to go about it:
- Get a catalytic converter that works well with your car.
- Ensure that you have about 15 liters of fuel in your tank.
- Follow the instructions on how to use catalytic converter cleaner with regard to the fuel/catalytic converter cleaner ratio.
- Pour the catalytic converter cleaner into the fuel tank.
- Drive your car at 2500rpm(at least) for about 30 minutes. The aim is to drive for long enough for the catalytic converter/fuel mixture to go around the car and clean the system. But make sure that the car does not overheat while on this drive.
- Re-calibrate the OBD code, after which you re-read the catalytic converter.
If at the end of the ride, you notice that the car accelerates quickly and there is less black smoke from the exhaust, then you might have unclogged the catalytic converter. It is one of the cheapest ways to fix a catalytic converter.
You might want to be wary of how you use some brands on which the jury is still out. Say, for example, the seafoam catalytic converter cleaner.
Unclogging the Catalytic Converter by Removing It
You should only undertake this method when you have tried the first method and it didn’t work out. Here are the tools you will need:
- Some automotive degreaser
- A large container
- Some penetrating oil
- A Floor jack
- Jack stands
- An impact wrench
- A pressure washer
Here’s how you go about this method:
- Let the exhaust system cool down to avoid getting burnt.
- Jack up the car and keep it suspended with jack stands.
- Take out the oxygen sensor(s).
- Apply some penetrating oil to loosen the bolts.
- Inspect the catalytic converter after removing it. If you hear a loud rattle, then you might want to stop because the components of the catalytic converter are most likely in pieces. If you don’t hear anything, then you should continue with the process.
- Use the pressure washer to wash the catalytic converter at low pressure.
- Immerse the catalytic converter in hot water and degreaser.
- Rinse the catalytic converter with the pressure washer at low pressure.
- Reinstall the catalytic converter after it has been allowed to drain and dry.
- Reinstall the oxygen sensor(s) after the catalytic converter is back in its place.
Professional Catalytic Converter Cleaning
When it comes to your vehicle’s catalytic converter, professional cleaning is often the best route for ensuring optimal performance and longevity.
Here’s everything you need to know about the benefits, methods, costs, and finding the right mechanic for the job.
#1. Benefits of Professional Cleaning.
Professional catalytic converter cleaning goes beyond what any off-the-shelf cleaner or DIY method can achieve. Certified mechanics use specialized equipment designed specifically for the task, ensuring a thorough and effective cleaning.
These tools can target hard-to-reach areas, breaking down stubborn carbon deposits that hinder performance.
Equally important is the expertise mechanics bring to the table. An experienced professional will not only clean the converter but also diagnose any underlying problems, such as engine issues that might be contributing to clogged components.
Plus, professionals handle the cleaning solutions responsibly, adhering to environmental regulations for proper disposal—something that’s often overlooked with DIY methods.
Trusting an expert ensures that both your car and the environment are cared for appropriately.
#2. Types of Professional Cleaning.
There are generally two key approaches mechanics might take for cleaning a catalytic converter:
On-Car Cleaning
This method involves cleaning the catalytic converter while it’s still attached to the vehicle.
Specialized tools and chemical cleaning solutions are introduced through the exhaust system, removing built-up residue without disassembling any parts.
This is often a faster, less expensive option.
Off-Car Cleaning
For deeper cleanings, the mechanic may remove the catalytic converter entirely. Once off the car, ultrasonic cleaning equipment or immersion in chemical baths can be used to thoroughly restore the converter.
This method is typically more intensive and reserved for severely clogged or malfunctioning converters.
Both methods rely on professional-grade tools and techniques that are much more effective than consumer-grade solutions or DIY attempts.
#3. Finding a Reputable Mechanic.
Choosing the right professional for catalytic converter cleaning is crucial to ensure quality service and avoid unnecessary expenses.
Here are some tips to help you find a trustworthy mechanic:
- Look for Certifications: Mechanics certified by organizations like the National Institute for Automotive Service Excellence (ASE) are trained and tested in their expertise, making them a reliable choice.
- Check Online Reviews: Browse reviews on platforms like Google, Yelp, or automotive forums. Positive feedback, detailed customer experiences, and high overall ratings are good indicators of a reputable service provider.
- Ask Questions: Don’t hesitate to ask the mechanic about their experience with catalytic converter cleaning, the tools and methods they use, and any warranties they offer on their work.
- Seek Recommendations: Word-of-mouth referrals from friends, family, or co-workers can often lead you to trusted professionals in your area.
How Do You Fix A Clogged Catalytic Converter Without Replacing It?
Replacing a clogged catalytic converter can be quite expensive. Thankfully, there are two ways to go about fixing a clogged catalytic converter without having to replace it:
#1. Cleaning It Without Removing It.
Here, you try to unclog the catalytic converter using a combination of fuel and a catalytic converter cleaner.
After mixing both elements in your fuel tank, you drive the car around at a relatively fast spend for an extended period. The fuel and the catalytic converter cleaner circulate throughout the car and flush out the pollutants.
#2. Cleaning It After Removing It.
This is a more complicated method that involves removing the catalytic converter and manually washing it. It is then reinstalled after it has been drained and dried. This method should only be tried as a last resort.
Maintaining Your Catalytic Converter
- Stay on Top of Maintenance: Regular oil changes and air filter replacements prevent contaminants from reaching your exhaust system.
- Fix Leaks Promptly: Address oil or coolant leaks as soon as they occur to avoid long-term damage.
- Drive Responsibly: Avoid aggressive driving or frequent short trips, which can lead to unburned fuel buildup.
- Use Quality Fuel: Premium fuel with fewer contaminants can help your catalytic converter last longer.
- Schedule Regular Inspections: Routine checkups at Dave’s American Discount Muffler can identify potential issues early.
how much does it Cost to Replace a Clogged Catalytic Converter?
The average cost for catalytic converter replacement is between $900 and $2,500, although some cars can cost far more. The reason for the high cost has nothing to do with the labor charges. In fact, most catalytic converters are simple to replace.
Instead, the cost is driven up due to the number of precious metals that are located within the catalytic converter.
The more metals a converter uses, the more you can expect to pay for it. Additionally, some vehicles use more than one converter, making the cost even higher if they both need to be replaced.
FAQs.
Q: Can A Clogged Catalytic Converter Be Cleaned?
Yes, but it all depends on the level of clogging. A slightly to averagely clogged catalytic converter can easily be cleaned. In such an instance, the clogging is mild and can easily be removed by fuel additives or by manually washing the catalytic converter.
However, there are extreme cases where an overly clogged catalytic converter is best replaced because it might be clogged beyond repair.
In such a situation, you will find that the exhaust has heated the catalysts to the point that they melt and can no longer catalyze the emissions from the exhaust.
Another situation is when the internal parts of the catalytic converter have come apart either because of physical impact or heat.
Q: What Are The 3 Most Leading Failures Of A Catalytic Converter?
Catalytic converter failure can be troublesome for both you and the car. It hampers the driving experience and can drain your pockets too.
It can also lead to engine failure if you don’t manage it on time. Here are the 3 most leading failures of a catalytic converter:
- Mechanical Damage
- Overheated/Broken Catalytic Converters
- Coated Substrate
Q: Can I Hit My Catalytic Converter With A Hammer?
Yes, you can. Part of the diagnostic process will require you to use an unclogged catalytic converter hammer to test the structural condition of the catalytic converter.
Every catalytic converter contains a substrate that can disintegrate due to physical impact or overheating.
If you hear a rattling sound when you hit the catalytic converter with the hammer, then the substrate has disintegrated, and the catalytic converter should be replaced, not unclogged.
Q: Can I Put Cataclean In a Full Tank?
Not if you want to get the best outcome. For one, putting some Cataclean in a full tank will cause the tank to overflow. Secondly, the mixture of fuel and Cataclean will not be “strong” enough to clear the pollutants.
To get the best results from using a Cataclean catalytic converter cleaner, you do not want to put it in a full tank of fuel.
The recommended quantity of fuel for best results is about 15 liters 15 liters of fuel will allow just the right concentration of Cataclean that is required to unclog your catalytic converter.
Final Words
You need not worry too much about catalytic converter-related issues once you know how to unclog a catalytic converter. You could easily apply any of the two methods described in the article to unclog your catalytic converter.
Unclogging your catalytic converter without removing it is the more manageable and cheapest way to fix a catalytic converter.
However, it is just a quick fix for a catalytic converter and is not as effective as unclogging the catalytic converter after removing it.
Both methods are great for unclogging catalytic converters for different reasons. However, there are scenarios where catalytic converters cannot be unclogged because of the level of damage. When this happens, your best bet is to replace the catalytic converter.