Repair cost guide

Exhaust and catalytic converter replacement cost in the UK

Exhausts rust from the inside out, and catalytic converters remain a target for thieves. Knowing which section has actually gone stops you paying for a full system you do not need.

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Typical UK exhaust prices

Most exhausts are made up of separate sections, so a good garage will replace only the part that has failed. Prices include fitting at around £70 an hour.

JobTypical UK cost
Rear silencer or backbox£100 to £250
Centre or mid section£150 to £350
Front pipe with flexi joint£150 to £400
Catalytic converter, aftermarket£250 to £700
Catalytic converter, original equipment£500 to £1,500
Lambda or oxygen sensor£120 to £300
Full system replacement£400 to £1,200
Cat protection cage or marking kit£150 to £350

What affects the cost

Which section has failed

A blowing joint or a rusted backbox is a cheap fix. A failed cat with contaminated internals is the expensive end, particularly if the OE part is the only one that satisfies the ECU.

Aftermarket or original

Aftermarket cats are far cheaper but must be type approved for your car. On some models a non-OE cat triggers an emissions warning light, so ask the garage what they recommend.

Corrosion and access

Seized clamps, rusted hangers and heat shields all add time, especially on salty coastal cars and anything over ten years old.

Why the cat failed

Cats rarely fail alone. Misfires, oil burning and rich running destroy them. Fitting a new cat without fixing the cause will just kill the new one.

Signs of exhaust trouble

  • A droning or blowing noise that gets louder under acceleration.
  • A rattle from underneath, often the heat shield or the cat internals breaking up.
  • The engine management light on with catalyst efficiency or lambda codes.
  • A strong smell of fumes or a sulphur, rotten-egg odour.
  • A sudden, very loud roar after parking in a public car park, which usually means the cat has been stolen.

How to pay a fair price

Ask for the failed section to be identified precisely before agreeing to a full system. Many garages will also weld a new flexi joint or section rather than replacing the whole pipe, which can halve the bill. Comparing local quotes on the same diagnosis is the surest saving.

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Frequently asked questions

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