The catalytic converter is an integral part of your car’s exhaust system, and a replacement can cost more than you think.
A catalytic converter is often abbreviated to “cat” – not to be confused with the furry pet that does whatever it wants. In the following text, I’ll be using both terms interchangeably.
In this article, I’ll be going through the cost of a replacement catalytic converter. To do this, we’ll first look together at how the exhaust system works and how the catalytic converter(s) contribute to this.
- What is a catalytic converter?
- Catalytic converter replacement cost
- Common catalytic converter questions
- Cataclean Review
- How To Unblock A Catalytic Converter – And How To Diagnose
- Check Engine Light Flashing – What’s Causing It?
- Straight Pipe Exhaust – Sound, Performance & Fuel Economy Explained
What Does A Catalytic Converter Do?
Here’s a characteristically-enthusiastic video from Donut Media to explain the cat to you.
A catalytic converter is one of the main parts of your exhaust to reduce its overall emissions.
Some have one, some have two, and some have multiple small ones. You also find “pre-cats” on many vehicles.
It uses chemical reactions to reduce the number of harmful gases that your exhaust throws into the atmosphere.
Primarily, it focuses on turning everything into water and carbon dioxide – CO2. Wait, what? Carbon dioxide? That ozone killing one?
That’s correct. The cat converts gases into water and CO2 because, although it’s doing an awful lot of damage, the alternative is much worse. Although carbon dioxide is single-handedly wreaking havoc in the world (something that’s entirely our fault as human beings), it’s less harmful than carbon monoxide, nitric oxide, and nitrogen dioxide (collectively, NOx), and hydrocarbons – all of which are potentially fatally toxic to us.
Especially in big cities and along busy stretches of freeway, the catalytic converter plays a considerable role in preserving nearby inhabitants’ air quality.
So, although we’re putting out carbon dioxide, we’re not breathing in all of those other things. It’s still not good, but it could be much worse.
How Does A Catalytic Converter Work?
The “catalytic” part of the name refers to how it acts as a catalyst (link to Cambridge Dictionary).
A catalyst, according to the Cambridge Dictionary, is
something that makes a chemical reaction happen more quickly without itself being changed
If you were to disassemble a catalytic converter, you’d find a honeycomb-like structure. The interior walls of this are coated with rare metals such as palladium, rhodium, and platinum.
These precious metals catalyze the redox reaction involving natural exhaust gases. Due to its being there, many more gases are converted before they leave the tailpipe.
What Are The Different Types Of Catalytic Converter?
There are two main types of catalytic converter: a two-way and a three-way.
By law, all cars should have at least a two-way cat.
All chemical equations come from chemequations.com.
A two-way catalytic converter changes carbon monoxide into carbon dioxide and hydrocarbons into carbon dioxide and water.
2 CO (g) + O2 (g) → 2 CO2 (g)
4 CH + 5 O2 → 2 H2O + 4 CO2
Nowadays, two-way converters are used almost solely on diesel vehicles. We’ll address all that in a little more detail at the end of the article.
A three-way catalytic converter is what you’d usually find in a gasoline- or petrol-powered car.
As well as converting carbon monoxide and hydrocarbons into carbon dioxide and water, three-way converters also convert nitric oxide (NO) and nitrogen dioxide (NO2) to nitrogen (N2), water, and CO2.
Collectively, NO and NO2 are known as NOx.
C (s) + 2 NO2 (l) → CO2 (g) + 2 NO (g)
2 CO (g) + 2 NO (g) → 2 CO2 (g) + N2 (g)
4 CO (g) + 2 NO2 (l) → 4 CO2 (g) + N2 (g)
2 H2 (g) + 2 NO (g) → 2 H2O (l) + N2 (g)
Where Does A Catalytic Converter Sit?
In most cars, it sits near the engine, just after the exhaust manifold.
Like everything and everyone, catalytic converters have an optimum working temperature. (For me, it’s about 80 degrees F in direct sunshine with a good breeze.)
On the other hand, they prefer a sweatier 750 to 800 degrees F to bring out the most efficient performance. For this reason, you often find them nearer the engine.
What Is The Cost Of A Catalytic Converter Replacement?
It’s difficult to put an exact number to this, as costs vary significantly depending on age, make, model, and general condition.
Converters are meant to last for the car’s entire life.
However, as a general approximation, you should expect to pay around $800 to $1,200. However, these figures can start from anywhere as low as $400 and go all the way up to $2,000 or $3,000.
These prices would include labor.
The cost of a catalytic converter replacement could be influenced by the following. This is a non-exhaustive list and it’s all really done on an individual case-basis.
- Engine size – the greater the engine size, the more gases it will release.
- The general physical size of the car.
- Local costs of labor in your state.
- How interwoven the cat is with your exhaust manifold.
- Whether you have a luxury model or not.
- The rarity of your car – the more common it is, the cheaper parts are likely to be.
When you buy a replacement catalytic converter, the cost usually also covers the exhaust pipe section surrounding it. Many modern exhausts are made up of two, three, or four different pipes connected via metal sleeves.
When you replace a cat, you remove these pipes one by one, starting at the tailpipe. When you’ve removed the one, including the catalytic converter, you’ll replace the entire pipe with your new one before reassembling the rest of the exhaust.
Many people use this as an excellent time to replace the entire exhaust from manifold to tailpipe.
Why Does A Catalytic Converter Cost This Much?
A significant part of this cost is those precious metals I mentioned earlier. Without them, the catalytic converter is nothing. Those metals are palladium, rhodium, and platinum.
In fact, when you scrap a car, having the catalytic converter still installed will be one of the highest value components of it, if not the highest.
According to Metals Daily, metals you often find within the cat are currently valued as follows:
- Palladium – currently ~ $2,600 per ounce.
- Rhodium – currently ~ $29,000 per ounce.
- Platinum – currently ~ $1,200 per ounce.
Comparing those numbers to the current prices for gold and silver might give you an idea of their ridiculous values.
- Gold – currently $1,700 per ounce.
- Silver – currently $26 per ounce.
By the looks of things, someday soon, the Olympics will have to be awarding rhodium or palladium medals!
Should I Take My Car To A Shop Or Do It Myself?
It is possible to do this kind of work yourself. However, it’s equally likely to mess it up royally.
In my experience, a job fitting an exhaust always goes one of two ways: easy as pie or knuckle-bruisingly wash-your-mouth-out-with-soap fantastically-infuriatingly badly.
A lot of it depends on your particular make and model, as well as how well someone fitted the previous exhaust and how good your mechanical skills are.
Overall, I would only recommend taking on this job if you have experience with welding. You may well need some. Of course, you might not, but that’s the decision that needs making—risk vs. reward.
If you decide to do all the work yourself, it should be cheaper, as you won’t have to pay out for labor costs.
To buy the part alone, cats usually cost less than $1,000 and probably closer to around $600. Here’s a link to OEMFord.parts with some OEM Ford cats and their prices, so you can see for yourself how much they vary.
Why Do Thieves Steal Catalytic Converters?
The cat is filled with precious metals, such as mentioned above.
This gives it a pretty high monetary value. When thieves steal catalytic converters, they’ll extract these metals and sell them on. In newer, high-end vehicles, the precious metals in just one cat can be worth up to several hundred dollars.
Currently, there’s no real way around it. There are a few steps you can take:
- Use anti-theft devices or get the bolts welded in around the exhaust.
- Park your car in a secure, locked area or somewhere with a large footfall.
- Etching the VIN onto the cat itself.
- Checking if your car insurance covers this particular incident.
Reports show a dramatic increase in thefts in 2019, with numbers being more than ten times that of the previous year.
What Are The Symptoms Of A Bad Catalytic Converter?
You should watch out for the following things, all of which can be signs of a bad catalytic converter. You’ll only notice these while driving or once you’ve parked up.
- Check Engine Light.
- Reduced acceleration and general engine performance.
- Black or dark exhaust smoke coming from the tailpipe.
- Sulfuric-ish smells coming from down low under the car, near the engine.
- If you can get under the car, you might feel excessive heat coming from the cat. (Don’t touch it – just put your hand near it. It will be unbelievably hot and burn you instantly.)
Most cars nowadays are equipped with oxygen sensors, also called lambda sensors. You’ll often find two of these – one before the cat and one after. When the cat isn’t working correctly, the oxygen sensor will detect this and alert you through the dashboard instrument cluster.
On that note, lambda sensors can also become clogged up. They are often pick up considerable amounts of carbon deposits and, as a result, stop working properly. Usually, you can quickly fix this by simply replacing the sensor.
Using an OBD code reader will often tell you if there may be something wrong with the cat.
Why Does A Cat Stop Working?
The main reason for a catalytic converter to stop working is it getting clogged up. These deposits are often made up of hydrocarbons that the engine didn’t adequately burn in the combustion chamber.
From there, they’ve been sent down the exhaust manifold and got stuck in the cat.
The deposits can also involve oil and coolant if you have some problem whereby they’re also getting burnt.
When the cat’s interior walls get covered with these deposits, they don’t react with the exhaust gases passing by them and block their passage. Because of this, your vehicle’s emissions output will be far higher and its power output drastically affected.
The cat could also stop working due to physical trauma, although it’s unlikely. Suppose you hit something hard enough to cause a crack or hole in either the cat itself or the pipe leading to it. Then, the exhaust gases may escape this way instead of going down the exhaust and through the converter.
If the cat got damaged enough to restrict exhaust gas flow, you could well end up with backpressure. This is really not good and needs immediate fixing (replacement).
How Do I Keep A Catalytic Converter Clean?
Good general maintenance and taking care of your car should do most of the work for you.
As mentioned before, the catalytic converter needs to get up to temperature before it starts working correctly. As a result, it’s most likely to wear out more quickly in cars that only travel short distances.
When the cat gets clogged up, it will stop working. In turn, this will affect your car’s emissions because the cat isn’t reducing them.
To stop your cat from getting clogged up, you can try:
- Driving on highways and freeways whenever possible and driving fast. Yes, it’s not just petrolhead-talk – it is actually good for your car. If this isn’t possible, I’ve found driving around town in a low gear to be quite effective too. It’s about maximizing engine rpm, not the car’s speed, for as long as possible. This works a bit like a flush for the whole system.
- Additives such as Cataclean. Follow the link to read a review of these products. You can put these into your fuel tank, and then, as you drive, they work to break down the carbon deposits within the exhaust.
- Maintaining your engine properly, in general, because problems such as blown head gaskets or broken piston rings can lead to oil and/or coolant getting into the engine. Once it gets combusted, the remnants are forced down the exhaust pipe and can clog up the cat.
- Using a call-out or in-house exhaust carbon cleaning service.
- Using premium fuel in your tank. I know it’s more expensive, but the longer-term benefits to your car more than outweigh this. When you put premium fuel in, there’ll be far fewer hydrocarbon deposits, meaning a lovely, fresh cat.
All of the above stop the cat from getting clogged up and, therefore, potentially save you a lot of money.
In my opinion, it’s worth giving them all a go if you realize your cat is on the blink. They are all considerably cheaper than replacing the component. If none of them work, then, unfortunately, you’re likely to need a new one.
What Are The Laws Regarding Catalytic Converters?
Is it legal not to have a catalytic converter?
All around the world, this seems to be somewhat of a gray area and people everywhere try to get away without having one.
It’s illegal to drive a car with no catalytic converter. The law states explicitly that you cannot modify a car’s exhaust or emissions system once you’ve bought it.
Are there any ways around this?
If you’re using your car on tracks alone (as in, you never drive it on the road), then you may use a straight pipe or other exhaust without a cat. In all situations on the road, it’s illegal not to have a cat.
People, inevitably, try to get around this. Some will use illegal exhausts and then replace the original whenever the car goes back in for an emissions test. Although this is a common trick, it is – bottom-line – illegal. If the police pull you over and discover that your car has no catalytic converter, it’ll be fines-galore for you.
Exhausts without cats generally don’t have mufflers either, so you end up with something that’s very, VERY loud. To the average petrolhead, that might be great. To your neighbors and everyone you drive past, not so much. And to the police, it’s a dead giveaway that you’re up to something, too.
If your catalytic converter stops working, for whatever reason, you must, legally, get it working again. You’ll often be able to get this done using one of the methods mentioned above. Sometimes, though, you’ll need to bear the cost of a catalytic converter replacement.
It doesn’t always make financial sense to replace the cat. Crunch the numbers. If your car doesn’t have a high sale value, it might be worth selling it and moving onto the next one.
Emissions laws are there for a reason, like them or not. The world is currently experiencing a mass climate crisis, whether people admit it or not. We must keep all environmentally-harming things to a minimum.
Catalytic converters don’t solve the problem, but they do help to keep it at bay while we find other alternatives to greenhouse gases.
Where Does The Abbreviation “Cat” Come From?
It’s quite literally just a short form of “catalytic converter”.
As you can tell, “catalytic converter” is quite a mouthful. Even to type it over and over again becomes quite repetitive.
Over time, the phrase “cat” has become more and more popular because, literally, it’s just easier to say.
What Is A Cat-Back Exhaust?
A cat-back exhaust is a legal modification that you can do to your car, provided you stay within local noise limits and regulations.
So named because it refers to the section of exhaust from the catalytic converter going back to the tailpipe, cat-back exhausts are an excellent way to increase noise levels and, to some extent, performance.
Cat-backs are aftermarket parts. They usually have a wide diameter than the stock exhaust fitted to the car during production.
Since the catalytic converter is still in place, cat-back exhausts are legal for road use. However, as mentioned, they must always conform to local noise regulations, so make sure to check yours before you buy anything.
With cat-backs, you will see some performance increase, but not too much. This increase comes from the wider diameter piping and reduced baffling in the muffler, meaning the gases can pass through quicker.
For your daily drive, you’re likely to be spending a lot of time at low revs, and therefore your stock exhaust often makes more economic sense.
Do Diesel Cars Have Catalytic Converters?
All cars with internal combustion engines have to have cats. Diesel engines are no exception.
Diesel engines produce much more particulate matter (PM) than gasoline/petrol engines. As such, they’re often paired with other environment-controlling components of the exhaust system.
The most common type of catalytic converter used in diesel systems is the diesel oxidation catalyst (DOC). These react with carbon monoxide, hydrocarbons, and PM to form carbon monoxide and water; however, they don’t react with NOx.
To keep NOx emissions down, diesel engines utilize EGR (exhaust gas recirculation). Modern vehicles might also use selective catalytic reduction (SGR) or a NOx absorber. SGRs are much cheaper and, therefore, more popular among manufacturers.
Most also utilize AdBlue, a brand name for urea injected into the exhaust. Here, the urea breaks down into ammonia due to thermal decomposition and hydrolysis and turns into ammonia. The ammonia reacts with the NOx and turns it into harmless nitrogen and water.
To address some common myths, AdBlue is neither blue nor made of pig urine. Manufacturers don’t have to make cars to use AdBlue, but it is a nice optional extra. It’s a selective catalytic reduction (SCR) technique. The trademark is owned by the VDA – the German Association of the Automobile Industry.
In addition to the catalytic converter, diesel cars use DPFs – diesel particulate filters. These are necessary because the cat only removes between 20% and 40% of the PM passing through it.
In the US, all diesel vehicles made after 2007 must have both a two-way catalytic converter and a PDF.
Is It Worth The Cost For A Catalytic Converter Replacement?
So, overall, is it worth it?
It’s not actually really a valid question, to be honest.
You need to have a working catalytic converter. By law.
And having a cat that doesn’t work will also affect your car’s performance negatively.
Therefore, the question isn’t so much about whether or not a replacement catalytic converter’s cost is worth it or not, but rather what the most sensible option for you is.
I would recommend trying every trick in the book to clean out your cat before installing a new one. If nothing works, it’s best to face the cost head-on and buy a replacement.
It might cost a lot, unfortunately. Owning a car tends to throw curveballs at us all the time.
But, once it’s fixed, you should be back on the road in no time.