Can you drive without a catalytic converter?
Yes, you could temporarily drive without a catalytic converter, and it won’t damage a modern car or engine.
But in the long run, it’ll emit harmful gas, sacrifice your car’s engine performance and fuel economy, and possibly get you in trouble with the law. This applies even if your catalytic converter has been stolen.
In this article, we’ll explain what catalytic converters do and why it’s illegal to drive without one. We’ll also cover what happens if you drive without a catalytic converter, how safe it is, and some helpful FAQs.
This Article Contains
- What Do Catalytic Converters Do?
- Can You Drive Without a Catalytic Converter?
- Is it Illegal to Drive Without a Catalytic Converter?
- Is it Safe to Drive Without a Catalytic Converter?
- What Happens if You Drive Without a Catalytic Converter?
- Other FAQs About Catalytic Converters
Let’s get started.
What Do Catalytic Converters Do?
Before exploring whether you can do without them, let’s understand what a catalytic converter does.
A modern car has a catalytic converter that rests between the car’s exhaust manifold and muffler. They turn harmful chemicals (like carbon monoxide) in your exhaust gas into carbon dioxide and water before exiting your car.
This not only reduces harmful emission trails but also improves your car’s fuel consumption and performance!
As you can see, the catalytic converter is one of your car’s most essential components.
So what would happen if you suddenly had to go without it?
Let’s find out.
Can You Drive Without a Catalytic Converter?
The short answer is yes.
Temporarily driving without a catalytic converter won’t damage your cars engine in any way. However, it may cause some performance issues.
The real question is: Why would you want to drive without one?
Driving without a catalytic converter will emit harmful exhaust gas into the atmosphere.
Plus, laws around catalytic converters and emission tests are very strict (for a good reason).
Unfortunately, these laws around the emissions test still apply even if your catalytic converter has been stolen.
Let’s take a closer look at the legal angle.
Is it Illegal to Drive Without a Catalytic Converter?
Yes, it’s illegal to drive without a catalytic converter in most states of the US. However, some exceptions made by the Environmental Protection Agency (EPA) make driving without a CAT legal.
While the law differs from state to state, it’s best to play it safe and ensure your vehicle always has a functioning catalytic converter fitted. The Clean Air Act of 1970 mandates that all vehicles must be fitted with carb compliant catalytic converters from the factory.
What if your vehicle didn’t come with a catalytic converter?
We’re glad you asked.
Most cars manufactured before 1970 (when the Clean Air Act was instated) didn’t come with factory-fitted catalytic converters. For this reason, some states (like Georgia) will allow you to pass respective emission checks if your vehicle is older than 25 years.
We’ve established that it’s generally illegal to drive without a CAT.
Now, let’s explore the safety aspect.
Is it Safe to Drive Without a Catalytic Converter?
Yes, you may be physically safe driving without a catalytic converter, but you won’t be legally safe (as mentioned above).
As a critical component of your car’s exhaust system, the catalytic converter reduces air pollution. So, driving with a broken catalytic converter (or no catalytic converter at all) won’t cause a crash.
Still, you’ll want to replace it as soon as you notice you have a stolen or failing catalytic converter!
Driving without your car’s catalytic converter means you’ll expel very high concentrations of carbon monoxide — an extremely harmful emission. Most deaths caused by carbon monoxide poisoning occur while operating a vehicle inside enclosed spaces.
Plus, if you have a bad catalytic converter (clogged, broken, or faulty catalytic converter), it’ll severely hinder your car’s engine performance.
Let’s look at how driving without a cat converter affects your vehicle.
What Happens if You Drive Without a Catalytic Converter?
There are a few tell-tale signs if you have a bad catalytic converter — or if it’s just not there anymore!
Here’s what you’ll likely notice:
- Loud exhaust pipe sound: If you find your catalytic converter stolen, the first thing you’ll notice is a louder exhaust pipe noise. You’ll also notice an increase in your car’s exhaust system volume when revving the engine — which is very difficult to ignore.
- Poor performance: Without a complete exhaust system, you’ll notice a significant decrease in engine power. Weak acceleration, stalling, and lack of power on inclines are dead giveaways that you may have issues with your car’s catalytic converter.
You may also notice an illuminated Check Engine Light, which happens when your car’s ECU no longer picks up oxygen sensor readings from the exhaust.
- Strong exhaust smells: Without a catalytic converter, your vehicle may emit potent smells (as well as deadly carbon monoxide gas, which has no smell at all). If ignored, these exhaust fumes could seep into the cabin, potentially causing a deadly mistake.
- Reduced fuel economy: When your car’s ECU notices a change in the concentration of exhaust fumes from the oxygen sensor, it’ll try to mend the imbalance by altering fuel levels and exhaust flow from the cars engine cylinders.
This will likely cause your fuel consumption to increase significantly.
Additionally, if the Check Engine Light is illuminated, the ECU might restrict engine power until the error has been resolved.
- Emissions failure: Vehicles must have carb compliant catalytic converters fitted in every state. If you go for a yearly inspection without one, you’ll fail the emission test.
Still have a few doubts?
Other FAQs About Catalytic Converters
Here are answers to questions you may have about catalytic converters:
1. Why Do Catalytic Converters Get Stolen, and How Do I Prevent It?
Catalytic converters contain many precious metal components, like palladium, rhodium, and platinum. These valuable metals react with nitrogen oxide to filter out any harmful gas. They also have high resale value for a catalytic converter thief.
To make matters worse, catalytic converters have very few identifying markers except a serial number. Once it’s off your vehicle, you probably won’t see it again.
Unfortunately, if you’re the owner of a low-emissions vehicle, you’re more likely to have your catalytic converter stolen, because the CATs on these models tend to have higher concentrations of valuable metals.
While it’s illegal to pay for scrap metals with cash, some merchants unfortunately still allow their purchases.
If you’d like to prevent catalytic converter theft, there are a few ways to do it:
- Install an anti-theft device on your catalytic converter: This will trigger an alarm when the device detects any tampering with the cat converter and works similarly to a vehicle alarm system. Anti-theft alarms are the best way to prevent catalytic converter theft.
- Paint your catalytic converter: Although it’s not the most effective way to prevent catalytic converter theft, painting your CAT will add an identifying marker — and, hopefully, make it easier to track down a stolen catalytic converter.
Tip: It’s best always to have car insurance for possibilities like catalytic converter theft. While having car insurance won’t save a stolen catalytic converter, it’ll take some weight off having to replace it.
2. How Much Does it Cost to Replace a Catalytic Converter?
Due to the precious metal components inside, a catalytic converter replacement isn’t cheap. A new catalytic converter can set you back between $400-$3000 — and that’s just for the part.
Considering labor, you could end up paying at least $1000 to replace your vehicle’s stolen or faulty catalytic converter.
Driving without a catalytic converter (or with a broken catalytic converter) can cause some serious air pollution and harm to your health. As a car owner, it’s your responsibility to get your vehicle’s catalytic converter repaired or replaced, even if it’s stolen.
While a catalytic converter replacement or repair can be pricy, it’s better to get them done as soon as possible — or risk facing unpleasantries with the law and Environmental Protection Agency during your next emissions test!
When the time comes to repair or replace your catalytic converter, why not contact RepairSmith?
RepairSmith is a convenient mobile vehicle auto repair and maintenance solution with expert mechanics. We‘ll give you competitive upfront pricing plus a 12-month warranty on all repairs!