Used Catalytic Converters
A catalytic converter cleans the exhaust gases before they leave the car, turning harmful gases into less harmful ones. It sits in the exhaust system, and when it fails the car may lose power, smell, or fail its emissions check. This page explains what it does, the signs it is failing, what to check on a used one, and how to enquire. Traceability records are kept for catalytic converters.
Call 07961 404768WhatsApp 07961 404768What a catalytic converter does
A catalytic converter is a box in the exhaust filled with a honeycomb coated in precious metals. As exhaust gases pass through, the metals trigger reactions that turn carbon monoxide, nitrogen oxides and unburnt fuel into carbon dioxide, nitrogen and water. It only works when it is hot, which is why it sits close to the engine.
The converter is matched to the engine and the exhaust system, and on many cars it is part of the manifold or the front pipe rather than a separate box. A converter from the wrong engine may look the same and still not fit, or may not clean the gases properly.
Signs a catalytic converter may need replacing
Converter trouble shows up in the way the car runs and in its emissions. The signs are worth acting on, because a blocked converter can damage the engine if it is left too long.
- A rattling noise from underneath, like loose stones in a tin
- A clear loss of power, especially when accelerating
- A smell of rotten eggs from the exhaust
- The engine management light staying on with emissions faults
- The car failing its emissions check
What to check before buying a used catalytic converter
Converters are matched to the engine and the exhaust layout, so the part number is the first check. Then look the unit over for damage, and ask what is known of it. Traceability records are kept for catalytic converters, and that record is part of how they are handled here.
- The part number matches the one on your car
- The casing is straight, with no dents or heavy damage
- There is no rattle from inside the unit when it is moved
- The flanges and fixings are straight and not corroded away
- Your mechanic has confirmed the converter will fit your car
How to enquire about a used catalytic converter
Give the registration, make, model and year of your car, and say whether your car is petrol or diesel. Converters differ between the two, and the registration is what pins down the right one.
You can enquire through the form, or by calling 07961 404768. Mention the symptoms — a rattle, a loss of power, or a failed emissions check — so the right unit can be checked first.
Frequently asked questions
What does a catalytic converter do?
A catalytic converter cleans the exhaust gases before they leave the car. Inside is a honeycomb coated in precious metals, and as gases pass through, reactions turn carbon monoxide, nitrogen oxides and unburnt fuel into less harmful gases. It only works when hot, so it sits close to the engine.
Why does my exhaust smell of rotten eggs?
A smell of rotten eggs from the exhaust usually means the catalytic converter is not working properly, and sulphur in the fuel is coming through as hydrogen sulphide. It can also mean the engine is running rich. Either way, it is worth having the converter and the engine checked.
Will a used catalytic converter fit my car?
Only if the part number matches, or your mechanic confirms it will fit. Converters are matched to the engine and the exhaust layout, and a unit from the wrong engine may look the same and still not fit or clean the gases properly. Give the part number when you enquire.
What is the rattle underneath my car?
A rattle from underneath that sounds like loose stones in a tin often means the honeycomb inside the catalytic converter has broken up. It is a common sign of a failed converter, and it should be checked promptly, as the broken pieces can block the exhaust.
What should I ask about a used catalytic converter?
Ask for the part number and whether the converter matches your car, and what it came from. Converters are matched by engine and by number, and traceability records are kept for every one. Give the registration when you enquire, and the number is checked against it.
Related pages
Looking for a used catalytic converter?
Call 07961 404768WhatsApp 07961 404768Autos Craft Ltd · 295 Cherrywood Rd, Birmingham B9 4UU, United Kingdom · Open 24 hours