Part explained
Catalytic converter: replacement, price, symptoms
The catalytic converter sits in the exhaust between manifold and centre silencer and converts CO, HC, and NOx into less harmful gases. It usually lasts a very long time — but the precious metals inside (platinum, palladium, rhodium) make it a theft target. This page covers symptoms, replacement cost, and how to find a fitting cat.
By the onderdelen.autos editorial team · Updated
What does the catalytic converter do?
A ceramic honeycomb coated with thin precious-metal layers. Hot exhaust gases pass through; the catalysts accelerate three reactions: CO → CO2, unburned HC → CO2+H2O, NOx → N2+O2. Result: 95%+ reduction in harmful emissions.
Signs of a failing or stolen cat
- Fault code P0420 or P0430 — catalyst efficiency below threshold.
- Persistent rotten-egg (sulphur) smell from the exhaust.
- Suddenly much louder under acceleration (post-theft).
- Power loss and higher fuel use (partial honeycomb blockage).
- Visual: a gap in the exhaust stream where the cat used to be.
When to replace
No interval — a cat usually lasts 200,000+ km. Replacement is reactive: failure, theft, or above-spec emissions. After theft: call the insurer first, photograph everything before proceeding.
What does a new cat cost?
New: € 250 – € 1,500 depending on engine size and number of lambda sensors. Used or reconditioned from Dutch dismantlers: € 80 – € 400. Workshop labour: 1 – 3 hours.
| Condition | From | To |
|---|---|---|
| New | € 250 | € 1500 |
| Used / refurbished | € 80 | € 400 |
Compare cats from Dutch sellers — often with warranty.
DIY?
Difficulty: Medium
Mechanically straightforward — unclamp, swap, clamp. The pain is in seized fasteners after years of heat. A torch helps.
- Socket set with extension
- Lambda sensor socket (22 mm slotted)
- High-temp installation paste
Frequently asked questions
Cost of a stolen cat?
Part + labour: € 400 – € 1,500. Comprehensive insurance often covers it.
Can I buy a used cat?
Yes, provided from a Dutch seller. Ask for a test reading — a burned-through cat triggers P0420 immediately.
Which cars are most targeted?
Hybrids (Prius, Auris) for higher precious-metal density. Also SUVs because they sit high.
What is a sport cat?
A 100/200-cell cat with less back-pressure. Legal only with EU type approval.
How to prevent theft?
Cat-shield or cage, garage parking, insurance check.
Related parts
Catalytic converters from Dutch inventory
Compare sellers by region — often with measurement and warranty.