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Should I Buy an Aftermarket Catalytic Converter?

So, you’ve come to the horrible realisation that your catalytic converter is going bad, and you’re looking for a new one. When it comes to catalytic converters being replaced, garages will normally give you two options: buy from the original equipment manufacturer (OEM), or buy one aftermarket. 

So, it’s time to weigh up your options. Should you buy an aftermarket catalytic converter or one from the OEM? 

In this article we explore that question, and its pros and cons. But first, let’s run through what exactly a catalytic converter is, and if it’s time for you to purchase a new one.

What is a catalytic converter? 

catalytic converter

Catalytic converters are an essential part of a car’s exhaust system. These converters control the emissions that your vehicle produces. Specifically, a catalytic converter prevents harmful toxins such as carbon monoxide and hydrocarbons from being released by converting them into less harmful pollutants. All petrol cars from 1993 onwards are required to have a catalytic converter.

Has my catalytic converter gone bad? 

a man fixing the underside of a car
Photo by Artem Podrez: Pexels

Maybe you’ve noticed that your engine seems to be underperforming or that your vehicle’s acceleration just isn’t what it used to be. This could be a sign that it’s time for a new catalytic converter. But what other signs are there?


A tell-tale sign that your catalytic converter is underperforming is that issues start to occur with your exhaust. If you’ve noticed dark fumes or a distinct smell of sulfur coming from your exhaust, then it is probably time to get a new catalytic converter fitted.

Gas mileage

Has your car been burning through gas like there’s no tomorrow? It’s possible that this is due to your catalytic converter experiencing issues. When a catalytic converter gets clogged up, it results in the engine using a lot more fuel than usual – so this is definitely a sign to look out for.


Occasionally, problems within your catalytic converter can cause your vehicle to misfire. This occurs due to the gas inside your car engine igniting, creating this effect. Issues such as these should be fully checked by a professional.

Whether you decide to replace your catalytic converter with an OEM part, or with an aftermarket part, is completely up to you.

What do we mean by aftermarket? 

a close up of car parts
Photo by Hebert Santos: Pexels

When we say aftermarket parts, what exactly do we mean? Well, we mean parts that are not made by the OEM. These vehicle parts are usually created to fit a variety of models and vehicles, and are a fraction of the cost. Perfect for those of you looking to save a few bucks.

Should I buy an aftermarket catalytic converter? 

underneath a car in a garage
Photo by Artem Podrez: Pexels

Now that you know what a catalytic converter is, and that you may have a problem with yours, there are a few options in terms of replacing it. Buying any part from the original equipment manufacturer (OEM) ensures top quality and top performance, but aftermarket parts can work equally as well. So, which should you choose?

Pros of buying an aftermarket catalytic converter 

The main benefit of purchasing an aftermarket catalytic converter is the immense discount on the part compared to one bought from the OEM. The original manufacturer will charge a premium price, and yes it will work effortlessly with your car, but so can an aftermarket catalytic converter in many instances. 

However, it is important to be aware of the disadvantages as well.

Cons of buying an aftermarket catalytic converter 

So, what are the cons to purchasing an aftermarket catalytic converter rather than one from the original equipment manufacturer?


The downside to buying any sort of aftermarket part is that it will not run as smoothly as an OEM part. This is due to the variety of quality that you will receive from one aftermarket catalytic converter to another, and this quality will never match that of an OEM.


From a money perspective, there is a disadvantage to picking the cheaper part. If an aftermarket part fails, and the driver has to buy an additional part, it can end up costing a lot more than if you had just purchased the OEM part in the first place. So, this is definitely something to consider if it’s the cost that’s swaying your judgment. 


When looking at this question from the standpoint of the original manufacturer, due to the fact that they created their catalytic converter to work perfectly with only one model, there is going to be a massive difference in performance. Aftermarket parts can work relatively well in a dozen different cars, but if you want seamless performance, buy from the OEM.


Also, buying from your car’s manufacturer will ensure that you have warranty over any faulty parts. If you choose to go aftermarket, it’s unlikely that you’ll be covered if anything goes wrong. This again links back to the cost side of things.

Conclusion: Should you buy an aftermarket catalytic converter? 

inside of a garage with a work bench and a car
Photo by AJ Yorio on Unsplash

We agree that buying any car part from the OEM can get pricey, but when it comes to the running of your vehicle, scrimping on cost can lead to more issues. 

The lower the cost of your car part, the more likely you are to receive a poor quality and average performing catalytic converter. However, if you’re looking for a quick, cheap fix, aftermarket products are not all bad. They can last, and may perform well – but it is not a guarantee. Weigh up your options and buy the part that meets your needs.


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