Problems After Using Cataclean and The Smart Fixes

In recent years, Cataclean has become one of the most popular fuel additives on the market. The product not only cleans the fuel system but, according to the manufacturer, the catalytic converter as well. Although there aren’t that many complaints of Cataclean damaging any of the car’s components, that can still happen, especially if you are not using it properly.

Some problems after using Cataclean that you might encounter include a damaged catalytic converter, damaged injectors or other fuel system components, and a check engine light. The check engine light usually comes on because Cataclean dilutes fuel and leads to a lean air/fuel mixture, or it throws off the emissions control systems.

how effective is cataclean

Common Problems after Using Cataclean

The following problems after using Cataclean are nowhere near as common as the title might lead you to believe, especially considering how popular Cataclean is. Moreover, all these problems happen almost exclusively because of misuse or failure to follow the manufacturer’s instructions. In other words, they don’t happen because Cataclean is a bad product.

Catalytic Converter Damage

The catalytic converter looks a lot like a muffler from the outside, but inside, instead of a pipe, it is a porcelain honeycomb structure that emulates hundreds of millimeter-wide exhaust passages. That’s also the reason why catalytic converters clog up much easier than other exhaust sections.

But over time, that honeycomb structure will begin breaking down and collapsing, resulting in a clogged exhaust and a car that won’t move or accelerate. And while Cataclean is designed to unclog the catalytic converter by removing carbon build-up from those tiny passages, it’s also highly abrasive.

The abrasiveness is good for carbon build-up cleaning, but if the honeycomb structure is already damaged, Cataclean could be its last nail in the coffin and start breaking it away. That results in a completely destroyed catalytic converter, but again, it will only happen if it is already on its last legs.

Injector and Fuel System Damage

In case you have used fuel additives before, you already know that they are meant to be added to a specific amount of fuel to avoid damage to the fuel system. That’s especially important with Cataclean because it’s much more abrasive than other fuel system cleaners.

If you use too much Cataclean or use it with too little fuel in the tank, it can damage the injector seals, the fuel filter, the fuel hoses, and even the fuel pump. That’s a lot of damage to risk for simply ignoring the Cataclean instructions printed on the label.

And because fuel injectors are most likely to fail, they will start leaking fuel into the oil pan when the engine is off. That dilutes engine oil and reduces its lubrication properties, ultimately resulting in a destroyed engine. But again, all of this rarely ever happens, so just use Cataclean as the manufacturer recommends, and there is no need to worry about anything. 

Check Engine Light Comes On

We already mentioned how fuel additives such as Cataclean dilute fuel. Well, if you add too much Cataclean, the fuel won’t burn as efficiently as it should and won’t be as combustible. That leads to a lean air/fuel mixture, poor performance, and poor fuel economy. But the main symptom you will notice is a check engine light triggered by the O2 sensor, which monitors the air/fuel mixture. The faulty codes you will see are P0171 and P0174.

Other than that, you might get all kinds of emissions system warning lights the car might have. Those can be the DPF warning light, EVAP system fault codes, catalytic converter efficiency faults, etc.

Fixing Problems Caused By Cataclean

Unfortunately, fixing some of these problems can be seriously expensive, so if you suspect any of them, it’s best to first have your car inspected by a professional. That’s unless you have a check engine light because of using too much Cataclean; you can solve that on your own.

Catalytic Converter Damage – Fixes

In case your catalytic converter has collapsed, be it because of too much Cataclean or because of age, wear, and tear, the only solution is to replace it. Other than that, some people may suggest deleting the catalytic converter, but that can cause other problems down the line, not to mention it’s illegal in most states and countries.

However, you can buy universal catalytic converters, which is probably the best option out there. Those converters rarely cost more than $150 to $250 brand new. Although that might still sound expensive, compared to a new OEM unit which can cost more than $800-$1,000, it’s a real bargain.

And lastly, don’t buy a used catalytic converter because you can never know if it’s damaged or not or how long it will last because the history of the vehicle it came off of plays a huge role in that.

Fuel Injector Damage – Fixes

If you suspect the fuel injectors are damaged, have them inspected by a professional. That’s especially important if your car has direct injection because those injectors can cost more than $300 apiece. Moreover, direct injection injectors can often be remanufactured or restored, which is cheaper than buying new ones.

But whatever option you go with, replacing them or fixing them is the only thing you can do. As for normal multi-point fuel injectors, those are much cheaper, and you can get them for as little as $50 apiece brand new. And regardless of how much they cost for your car, fixing them as soon as possible is crucial to avoid further engine or catalytic converter damage.

Check Engine Light – Fixes

In case you have added too much Cataclean, or there was too little fuel in the tank before you slushed it into the tank, you need to reverse the fuel dilution. The best way to do that is to add more fuel to the tank; pretty simple.

Also, it may take a while before the fresh fuel reaches the engine but don’t worry; it will reach it eventually. But while you are waiting, it’s a good idea to reset the ECU (engine control unit) using an OBD2 diagnostics tool and delete the stored fault codes.

cataclean instructions

What are the Benefits of Using Cataclean

The main benefit of using Cataclean is that it cleans the catalytic converter. Usually, when cleaning the catalytic converter, you need to remove it and use special tools or highly abrasive and dangerous chemicals. Now, removing the catalytic converter can be an extremely difficult job, even without the health hazards. And with Cataclean, you avoid all of those risks.

Furthermore, Cataclean doubles as a fuel system cleaner, so you avoid having to spend your money on two separate products. Next, Cataclean also cleans the carbon build-up on intake valves if your car has multi-point injection. Other than that, it can somewhat clear up the combustion chamber and pistons, but it’s nothing revolutionary.

All in all, Cataclean is an extremely good product that has been around for a fairly long time now. Moreover, there are almost no negative reviews, and as long as you stick to the manufacturer’s instructions, you shouldn’t worry about any of the above-mentioned problems.


Is Cataclean safe for engines?

Yes, Cataclean is entirely safe for engines. Cataclean is a well-established brand, and its products are designed for use in both diesel and gasoline engines. So far, the only problems that customers have reported when using Cataclean have been because of misuse.

Why is my engine light on after Cataclean?

If your engine light is on after using Cataclean, it could be because you used too much of it with too little fuel in the gas tank. Adding more fuel to the tank will solve the problem. Besides that, there could be something else wrong with the engine unrelated to Cataclean.

Will Cataclean clear the check engine light?

Yes, Cataclean can clear the check engine light. If your check engine light is caused by inefficient injectors or a clogged catalytic converter, the check engine light could go out after using Cataclean. But if something more serious is triggering the warning light, Cataclean won’t help.

Can I use 2 bottles of Cataclean?

No, it’s not recommended that you use 2 bottles of Cataclean. Use only one bottle of Cataclean with the fuel tank one-third full. That said, you can use Cataclean multiple times, but make sure there is a three-month gap between each application.

How long does it take Cataclean to work?

It usually takes around 15 minutes of driving for Cataclean to reach the engine and start doing its job. However, the cleaning process isn’t finished until you use up all the fuel that’s mixed with Cataclean.

Does Cataclean really clean O2 sensors?

Yes, according to the manufacturer, Cataclean does clean O2 sensors. However, O2 sensors rarely get dirty, and the product probably won’t be as efficient by the time it reaches the O2 sensor.

Can I use 4 bottles of Cataclean?

No, you should never use more than one bottle of Cataclean per application. You can use multiple bottles of Cataclean, but only with at least a three-month delay between each use.

Is it ok to use Cataclean twice?

Yes, it’s ok to use Cataclean twice. You can use Cataclean as many times as you like as long as you make a pause of at least three months between each use.

Will Cataclean clean injectors?

Yes, according to the manufacturer, Cataclean will clean injectors. As a matter of fact, cleaning the injectors is one of the main tasks of the Cataclean fuel additive, including cleaning the catalytic converter and valves.

What is the best catalytic converter cleaner on the market today?

According to, the top five catalytic converter cleaners are Hi-Gear HG3270s, Solder-It CAT-1, Oxicat, Cataclean, and CRC Guaranteed to Pass.

Final Words

In the end, the potential problems after using Cataclean are few and include a check engine light, damaged injectors, and a damaged catalytic converter. However, as long as you use Cataclean according to the manufacturer’s instructions, none of these problems will happen, so you should not worry.

Ibro Cehic

Ever since I was bitten by the automotive bug during early childhood I was obsessed with cars. My first driving experience came when I was ten and I already started tinkering with cars and motorcycles at thirteen. So, right from the beginning, I knew my life would revolve around cars, even if I wasn’t sure how that would happen. And today, thanks to my second passion, writing, I get to share my love for automobiles with other enthusiasts through my articles.

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