Is it a big job to replace a catalytic converter?

In short: for most cars it's a moderate job—typically 1–3 hours for a bolt-on catalytic converter, but longer if the unit is welded in, rusted in place, or hard to reach. The rest of this article explains why the workload varies, what affects cost, and how to approach the repair.

What makes it a big job?

Below are the main factors that influence how challenging a catalytic converter replacement can be. They determine whether the job is quick and straightforward or lengthy and labor-intensive.

• Access and location: The cat sits along the exhaust path under the vehicle; if it’s tucked behind other components or in a tight space, removal becomes fiddly.


• Mounting type: Bolt-on cats are usually easier to swap than welded-in units that require cutting or exhaust-pipe work.


• Absence or presence of oxygen sensors: Each sensor must often be removed and reinstalled or properly sealed to avoid leaks; damaged sensors add cost and time.


• Condition of surrounding exhaust: Rusted flanges, broken hangers, or a corroded exhaust system can complicate removal and installation.


• Need for cutting or welding: Some cars require cutting out the old converter and welding in a new one, which adds time and requires a welder.


• Safety and protective steps: Working under a car exposes you to heat, fumes, and stored energy; proper jacking, stands, and PPE are essential.

Conclusion: If the cat is bolt-on, accessible, and the exhaust system is in decent condition, the job tends to be a straightforward 1–3 hour fix. Welded-in units, severe rust, or a hard-to-reach layout can push the job into half a day or more and may involve replacing additional exhaust components.

DIY or hire a professional?

Deciding whether to attempt the replacement yourself or hire a shop depends on your tools, skill level, and the vehicle design. Here are common considerations:

• Cost savings: Doing it yourself saves labor charges, which can be a sizable share of the total bill.


• Complexity and risk: If welding is required, you’ll need proper welding equipment and expertise to ensure a leak-free seal and to avoid damaging sensors.


• Tooling and access: Limited space under certain cars can make even bolt-on jobs awkward without the right lifts or stands.


• Emissions and warranty: A professional installation helps ensure the right fit and emissions compliance; some factory warranties or state inspections may require professional service.


• Quality and safety: Professionals typically provide a leak test, torque verification, and a drive-cycle check of the oxygen sensors.

Conclusion: For many, a bolt-on, easily accessible converter is within DIY reach; for welded-in units, rusted hardware, or vehicles with tight underbody access, a professional shop is often the safer choice.

Cost and time you can expect

The total price of a catalytic converter replacement depends on parts and labor, as well as vehicle design and local rates. Here's a practical breakdown to help plan.

• Parts cost: Aftermarket direct-fit converters for common cars typically run from about 150 to 600, while higher-end OEM-equivalent units can be 500 to 1,600 or more, depending on the model and the number of cells in the converter.


• Labor time and rate: Labor commonly takes about 1–3 hours for a bolt-on replacement. Shop rates vary by region but often fall in the 75–150 per hour range; expect roughly 75–450 in labor charges.


• Total expected cost: All-in, most bolt-on replacements fall in the 300–1,100 range, with higher figures for difficult-to-access cars or premium brands.


• Additional costs: Replacement oxygen sensors if they’re fouled or damaged, new gaskets or clamps, and potential state emissions testing fees.


• Theft considerations: In high-theft areas, you may see increased prices or longer wait times for steel-cat replacement and anti-theft measures.

Conclusion: For a typical mid-range car, plan on a few hundred dollars for a DIY or shop job; luxury or EU models can push costs higher due to parts or labor complexity.

What to expect during the replacement

Here is a concise sequence of steps a shop (or a skilled DIYer) will generally follow to swap in a catalytic converter.

1. Confirm the replacement is necessary by checking diagnostic codes and evaluating exhaust flow and emissions readings.


2. Raise and secure the vehicle, then locate the catalytic converter and any sensors connected to it.


3. If necessary, remove heat shields and detach sensors or oxygen sensors from the converter.


4. Unbolt (or cut, if welded) the old converter from the exhaust pipes or manifold; remove the unit.


5. Prepare the mounting surfaces and install the new converter, re-attaching clamps or flanges and torquing fasteners to spec.


6. Reinstall any sensors, seal gaps, and verify that there are no exhaust leaks.


7. Start the engine and run a quick check for leaks, unusual noises, or sensor faults; perform a drive cycle to clear codes and allow the ECU to adapt.

Conclusion: The process is straightforward for a well-equipped shop or a capable DIYer on a bolt-on unit, but it can be longer if welding is required or parts are corroded.

Summary

Replacing a catalytic converter is typically a moderate repair rather than a heroic one. The main determinants are how the unit is mounted, how accessible it is, and whether welding or extensive exhaust work is required. Budget for parts and labor accordingly, and decide between DIY or professional service based on tool access, safety, and local emission requirements. When in doubt, consult a licensed mechanic or exhaust specialist to ensure the replacement is done correctly and compliant with local rules.

Will my car run better with a new catalytic converter?

Yes, replacing a clogged or faulty catalytic converter can significantly improve performance by restoring lost power, acceleration, and fuel efficiency. A new, properly functioning converter reduces exhaust back pressure, allowing the engine to run more efficiently and powerfully. 
This video explains how a catalytic converter works and what happens when it gets clogged: 50sHigh Performance AcademyYouTube · Mar 24, 2025
How it helps

• Restores power and acceleration: A clogged converter creates back pressure, forcing the engine to work harder and leading to sluggish performance and poor acceleration. A new one removes this restriction. 
• Improves fuel efficiency: By optimizing engine combustion, a new converter helps the engine run more efficiently, which can lead to better gas mileage. 
• Reduces engine strain: A failing converter can stress the engine. A replacement helps reduce this wear and tear, potentially extending the engine's life. 

What to consider

• High-flow catalytic converters: For performance-oriented vehicles, high-flow catalytic converters are designed to allow even more exhaust to pass through, leading to further gains in horsepower and torque.
• Legality: Removing or replacing a catalytic converter with a non-compliant one is often illegal and can lead to failed emissions tests, as Thermal R&D Exhaust explains. 

This video discusses the benefits of high-flow catalytic converters for performance vehicles: 59sBullnoseGarageYouTube · Nov 14, 2024

How much does it cost to replace a catalytic converter?

The average cost to replace a catalytic converter ranges from $500 to $2,500 or more, with the part costing $300 to $2,500 and labor costing $70 to $130 per hour. Factors like your vehicle's make and model, the number of converters it has, and whether you choose a direct-fit or universal part influence the final price.
 
Cost breakdown

• Parts: The cost of the catalytic converter itself can range from about $300 to $2,500 for direct-fit options. 
  • Universal converters: are cheaper ($100-$500) but require professional welding for installation. 
  • High-end or luxury vehicles: often have much higher prices due to the precious metals and advanced technology they use. 
• Labor: Expect to pay between $70 and $130 per hour for installation. The total labor cost depends on the complexity of the job and how long it takes. 
• Additional costs: There may be extra charges for related parts that need replacement, such as oxygen sensors or gaskets. 

Factors that affect the price

• Vehicle Make and Model: Luxury cars, SUVs, and trucks are generally more expensive to repair than economy cars, partly due to the higher cost of their specific replacement parts. 
• Number of Catalytic Converters: Some vehicles have more than one catalytic converter, which will increase the overall cost. 
• Type of Converter: Choosing a factory original (OEM) part will be more expensive than an aftermarket or universal one. 
• Emissions Standards: In states like California, New York, or Colorado, you may be required to purchase a more expensive, certified converter that meets stricter standards, explains CarParts.com. 
• Warranty Coverage: Check if your vehicle is still under its emissions warranty. The EPA mandates that major emissions components like catalytic converters be covered for at least eight years or 80,000 miles, whichever comes first. 

To get an accurate estimate

1. Check your vehicle's warranty: ConsumerAffairs suggests this is the first step before considering a replacement. 
2. Provide your car's information: Give your mechanic your vehicle's year, make, model, and VIN so they can find the correct part and give you an accurate quote. 
3. Ask for a detailed breakdown: Request a quote that clearly separates the cost of the part, labor, and any other parts needed.
4. Compare quotes: Get estimates from multiple shops, including exhaust specialists, to ensure you're getting a fair price. 

How long do catalytic converters take to replace?

All up, this process for replacement of the catalytic converter can take about two hours to complete.

Is replacing a catalytic converter worth it?

Yes, replacing a catalytic converter is often worth it because it's essential for legal and safe operation, restores engine performance, and prevents further engine damage. Driving without a working converter is illegal in many states, will cause your car to fail emissions tests, and can lead to reduced acceleration, poor fuel economy, and potential damage to your engine from overheating or backpressure issues. 
This video explains the cost difference between OEM and aftermarket catalytic converters: 51sKenny GillisYouTube · May 8, 2023
Reasons to replace a catalytic converter

• Legality and emissions: Many states require functioning catalytic converters to pass emissions tests and register your vehicle. Driving without one is illegal and can result in fines. 
• Engine performance: A failing converter can cause a noticeable drop in performance, including sluggish acceleration and reduced power. 
• Engine longevity: A clogged converter creates backpressure, which can strain the engine. It can also lead to overheating and further damage from unburned fuel or contaminants. 
• Environmental impact: The converter's primary purpose is to convert toxic gases into less harmful ones. A bad converter releases pollutants into the air. 
• Fuel economy: A properly functioning converter helps the engine run more efficiently, which can improve fuel economy. 

When to consider replacement

• Engine codes: A check engine light often indicates a problem with the catalytic converter (e.g., DTC code P0420). 
• Physical signs: You might hear a rattling noise from the exhaust or see dark smoke coming from your tailpipe. 
• Performance issues: Noticeable power loss, slow acceleration, or engine misfires are all signs that the converter may be failing. 

This video discusses the potential issues with aftermarket catalytic converters: 1mADVANCED LEVEL AUTOYouTube · May 3, 2021
Factors that influence the decision

• Extent of damage: A small crack might be repairable, but significant internal damage or a complete blockage requires replacement. 
• Repair vs. replacement: While repairs can be cheaper upfront, a replacement provides long-term reliability and ensures you meet emissions standards. A failed cleaning attempt can sometimes cost as much as a new one. 
• Cost: The cost varies based on the vehicle, type of converter (OEM vs. aftermarket), and labor costs. However, the cost of potential engine damage and failing to pass inspection often makes replacement the more cost-effective choice in the long run. 

This video shows a step-by-step process for replacing a catalytic converter: 55sScrew This!YouTube · Aug 9, 2023