catalytic converter replacement

What does a catalytic converter do?

A catalytic converter is a key component of your exhaust system. It changes harmful substances in a car’s exhaust gasses, such as carbon monoxide nitric oxide, and hydrocarbons, into less harmful gases, such as water vapour. Every car registered in the UK must have a catalytic converter fitted by law. It became standard for petrol vehicles in 1992, and 2001 for diesel cars.

A typical catalytic converter is made of ceramic blocks with a porous structure. By coating the pores with a selection of valuable metals: platinum, rhodium and palladium, they act as a filter to break down the toxic exhaust gases produced by burning petrol.

The metal coatings work far better as filters when they’re heated, so their position next to the engine offers the ideal environment for just that. The converter can then perform the chemical reaction required to break down the poisonous gasses into less harmful products with much greater ease.

How often should a catalytic converter need replacing?

A catalytic converter will usually need to be replaced after 70,000-100,000 miles, or if you begin to experience any of the above symptoms. Regular maintenance and checks (including an MOT) will determine whether you need to replace your converter or if it’s good to go for a few more miles.

How you drive, and the typical usage of your car, will affect its lifespan too. Your converter could wear out quicker if your car is predominantly used for short journeys in stop/start traffic. Your converter works better at a required temperature, so if it’s not getting the chance to heat up properly, it isn’t going to be as efficient. This could shorten its effective life.

The law, vehicle regulations and your MOT

Your vehicle’s emissions will be measured during your MOT test. If your car is found to break the legal limits, then that’s an immediate fail.

In 2020, almost 1.3 million vehicles failed their MOT test last year due to dangerously high emissions. If you’re trying to keep your motoring costs down, then MOT retests are easily avoidable with regular checks and good car maintenance.

What happens during a catalytic converter replacement?

Our certified mechanics will:

• Raise your car completely off the ground, making sure that the exhaust has had time to cool down before they begin the replacement.

• Locate the catalytic converter. It usually looks like a box in the middle of the exhaust system underneath the car.

• Remove the catalytic converter, inspect it and fit a replacement if necessary

• Test the new catalytic converter, taking care to double check that the replacement catalytic converter is up to the correct specifications for the vehicle’s emissions standards.

What causes a catalytic converter to break?

Most catalytic converters will last the lifetime of a vehicle. But in some cases, a converter will go bad and need to be replaced. Almost all problems with a catalytic converter are due to an engine issue. It is usually caused by excess fuel entering the exhaust system due to an incorrect air/fuel mixture, failing spark plugs, incorrect engine timing, a faulty oxygen sensor, or other issues where fuel leaves the engine’s combustion chamber unburned.

When this happens, the catalytic converter gets too hot and begins to melt, causing significant performance problems. Without proper maintenance, carbon deposits can also clog the catalytic converter, or worst case, block it completely.

When should a catalytic converter be replaced?

The expected lifespan of a catalytic converter is usually between 70,000 and 100,000 miles. Regular maintenance and checks (including an MOT) will determine whether you need to replace your converter or if it’s good to go for a few more miles.

How you drive, and the typical usage of your car, will affect its lifespan too. Your converter could wear out quicker if your car is predominantly used for short journeys in stop/start traffic. Your converter works better at a required temperature, so if it’s not getting the chance to heat up properly, it isn’t going to be as efficient. This could shorten its effective life.

What are the symptoms of a bad catalytic converter?

Usually, there a few signs you can look for:

• Significantly reduced engine performance.

• Dark smoke is coming from the exhaust.

• Poor fuel efficiency.

• If you experience issues while accelerating.

• If you can smell sulfur (rotten eggs) coming from your car.

• When the ‘check engine’ warning light illuminates.

How often should you replace your catalytic converter?

A catalytic converter will usually need to be replaced after 70,000-100,000 miles, or if you begin to experience any of the above symptoms. Regular maintenance and checks (including an MOT) will determine whether you need to replace your converter or if it’s good to go for a few more miles.

How you drive, and the typical usage of your car, will affect its lifespan too. Your converter could wear out quicker if your car is predominantly used for short journeys in stop/start traffic. Your converter works better at a required temperature, so if it’s not getting the chance to heat up properly, it isn’t going to be as efficient. This could shorten its effective life.

What happens during a catalytic converter replacement?

Our certified mechanics will:

• Raise your car completely off the ground, making sure that the exhaust has had time to cool down before they begin the replacement.

• Locate the catalytic converter. It usually looks like a box in the middle of the exhaust system underneath the car.

• Remove the catalytic converter, inspect it and fit a replacement if necessary

• Test the new catalytic converter, taking care to double check that the replacement catalytic converter is up to the correct specifications for the vehicle’s emissions standards.

What is the average life of a catalytic converter?

This can vary from car to car and from driver to driver, however the estimated lifespan of a catalytic converter is between 70,000-100,000 miles, or if you begin to experience any of the symptoms previously mentioned.

Can you drive with a broken or missing catalytic converter?

Your car will most likely still be drivable, however bad catalytic converters are terrible for the environment, and driving without one is even worse. A blocked or damaged converter can cause further damage to your car, resulting in a more expensive repair in the long run.

There are strict regulations and laws around vehicle emissions, therefore if you get caught by the police with a broken or missing catalytic converter you may be fined.

What happens if you don't change a broken catalytic converter?

Failing to replace a catalytic converter can result in more damage to your car, poor fuel efficiency and a potential fine from the police. If the converter has begun to function poorly due to it being clogged up, it will cause the vehicle to run extremely poorly.