What Is a Catalytic Converter and What Does It Do?

Posted: April 16, 2026

A catalytic converter is a part of your vehicle’s exhaust system that reduces harmful emissions by converting toxic gases into less dangerous ones. It contains valuable metals like platinum, palladium, and rhodium, which make it worth money even after it stops working.

What’s Your Catalytic Converter Worth?

What’s That Part Under Your Car You’ve Never Thought About?

You’ve probably never given much thought to that bulky, metallic unit bolted beneath your car—until it fails or gets stolen. That’s the catalytic converter, and while its name might sound complicated, its job is simple: protect the environment and help your vehicle run cleaner.

Catalytic Converter Basics

Every gas-powered car and truck made in the last few decades has a catalytic converter. It’s typically located in the exhaust system between the engine and the muffler, and from the outside, it looks like a small metal canister or a section of pipe with heat shields.

But inside that steel exterior? That’s where the real work happens.

The Purpose: Reducing Harmful Emissions

Catalytic converters reduce vehicle pollution by transforming three major exhaust pollutants:

  • Carbon monoxide (a poisonous gas)
  • Hydrocarbons (from unburnt fuel)
  • Nitrogen oxide (which causes smog)

They convert these into carbon dioxide, water vapor, and nitrogen gas—harmless compounds that are far safer to release into the air.

What’s Inside a Catalytic Converter?

Inside the converter is a ceramic honeycomb structure or a metal foil coated with:

  • Platinum
  • Palladium
  • Rhodium

These precious metals act as catalysts, speeding up chemical reactions without being consumed. Because they are rare and expensive, they give old converters their scrap value.

Why They’re Valuable Even After Failing

Even when a converter stops working correctly, it still contains trace amounts of precious metals. These can be recovered and reused through a specialized recycling process. That’s why scrap catalytic converters are in such high demand—and why thieves often target them.

Scrap buyers like RRCats specialize in grading, quoting, and buying these used converters based on their remaining metal content.

When and Why Catalytic Converters Fail

Converters can fail over time due to:

  • Excessive fuel in the exhaust (which overheats the converter)
  • Contamination from oil or coolant
  • Physical damage or rust
  • Age and mileage

When this happens, your vehicle may trigger a check engine light, fail an emissions test, or start running poorly.

Don’t Throw Money Away

Replacing your catalytic converter?
Don’t throw the old one away—recycle it for cash.

RRCats makes it easy to sell your used converter, with free quotes, quick shipping, and fast payment options. Your old part may be worth more than you think.

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Check corners, under shields, and down pipes for numbers. Not all catalytic converters have numbers.
Drag & Drop Files, Choose Files to Upload You can upload up to 10 files.
To get a quote sooner, attach photos of any serial numbers and an overhead pic of the catalytic converter(s).
Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.
Upload a Photo: Please include a clear photo of one of the following documents: Vehicle or equipment, Registration, Title, or Bill of Sale. Why do we need this? We are required by law to verify proof of ownership before purchasing certain equipment or materials to prevent theft and ensure lawful transfer. For more details, refer to New Jersey Scrap Metal Laws – N.J.S.A. 13:1E-99.12 (or insert exact link to the statute you want to reference). This requirement is mandatory to receive a quote.

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