A catalytic converter, also known as “cat”, is a small but important part of your vehicle. But do you know what this crucial piece of equipment does? If you’re in the dark about your catalytic converter, we at BookMyGarage created this guide to shed light on the subject.
What is a catalytic converter?
A catalytic converter is often located close to the engine as it works best at high temperatures. It takes the noxious gasses created by the engine and converts them into harmless emissions which exit from the exhaust via a chemical reaction. When petrol is burned by an engine, a cocktail of toxic fumes is created. These include hydrocarbons, carbon monoxide and nitrogen oxides. A catalytic converter transforms these harmful gases into oxygen and water vapour. This reduces emissions and prevents smog.
Is it fitted in every car?
Catalytic converters have been mandatory pieces of equipment on any new petrol-engined car built from 1993.
Diesel cars are now fitted with a diesel particulate filter (DPF), made mandatory in 2009. DPF traps excess exhaust soot by burning it off, reducing harmful pollutants released into the atmosphere. Because the combustion within the petrol and diesel engines is different, the DPF and the cat work differently.
How long does a catalytic converter last?
Many factors impact the lifespan, but generally, a catalytic converter should last between 70,000 and 100,000 miles. This can be affected by how the car is used. For example, a car used for only short start/stop journeys for most of its life could wear the cat down more quickly, because none of the components are warming up to their optimum operating temperature often enough. Equally, a high mileage car that’s led a hard-working life can also age the cat.
How much does a catalytic converter cost?
Our research shows that catalytic converter prices differ according to a range of factors including the make, model, engine size and year the car was made as well as the fault with the catalytic converter itself. Catalytic converter parts are likely to cost from somewhere between £150 to £850! When the 1-2 hours it takes a mechanic to replace your catalytic converter are factored in, you could be looking at a repair bill somewhere around £1000.
Those numbers are eye-watering which is mainly because of what makes up a catalytic converter. Inside the metal casing, there are two ceramic blocks which look like a honeycomb. This is coated with a mix of precious materials such as palladium, platinum and rhodium. Platinum costs about £25 a gram and Rhodium £20 a gram. So, a minute amount of either material can increase the cost of a cat significantly. Also, most modern cars have their catalytic converter integrated into the engine manifold which means you need to replace both, increasing the cost.
Warning signs that your catalytic converter is faulty
It is important to be aware of the warning light the car displays. This may either be the engine warning management light or a specific catalytic converter warning light. The graphic on your vehicle may be generic such as the graphics below. But it’s sensible to check your car’s handbook, to ensure you are familiar with all warning lights.
If your warning light comes on at any point, you should get a reputable garage to check your engine. It could be a false alarm, or it could lead to a more serious problem.
Other symptoms to look out for include:
- Engine runs rough.
- Increased fuel consumption.
- Increased emissions.
- Car fails an emissions test.
- The car does not accelerate as well as usual.
- The engine does not accelerate past a certain RPM (usually idle speed).
- Engine cuts out (due to additional backpressure).
What can go wrong with your catalytic converter?
As Chris Riley, manager at Formula One Autocentres in Brentwood, Essex explains, “The most common issue with catalytic converters is that the ceramic block inside gets clogged with carbon deposits, or starts to break down if it has worked at too high a temperature over a long period. This can cause the engine warning light to come on if the car detects a problem.” Similarly, rapid cooling can also damage the structure of the catalyst and obstruct the exhaust pipe.
Another component which could be faulty is the Lambda Sensors. This is also called oxygen sensors, and as the name suggest they measure the oxygen content of exhaust gases.
Any problems with either of these components could decrease the efficiency of your engine. It could also cause a higher amount of toxic fumes to be pumped into the atmosphere. In some extreme cases, your engine may stop working altogether.
MOT and your catalytic converter
If a vehicle’s emissions are too dirty, it will fail its MOT. In 2018, over 744,000 vehicles failed their MOT due to dangerously high emissions.
The authorised MOT tester will advise you on whether or not the fault lies with the catalytic converter, and what steps to take to fix the problem. If your vehicle is over ten years old, the fault is likely to be the catalytic converter, but always seek a professionals’ opinion just in case the real culprit is something much more fiddly and sinister. If the other parts of the engine are faulty, extra-dirty fumes may be pumped into the cat, leaving it overwhelmed. Investing in a good catalytic converter cleaning fluid can help increase its performance and lifespan, especially if you mainly use your vehicle for short journeys.
What are the options for replacing it?
There are two options: get the official manufacturer to replace the part or source aftermarket repair parts from a reputable dealer, such as Eurocarparts. Genuine manufacturer parts are manufactured to the correct tolerances for a correct fit. In addition, they come with a full manufacturer-backed warranty and the dealer’s labour is covered by a guarantee as well. On the other hand, aftermarket parts are often cheaper and usually come with a three-year warranty. However, because of the price difference the quality, longevity and fitment may not be as good as the original equipment parts.
An approach canny drivers might choose to take is to have their local, independent garage order the genuine, original part from the vehicle’s manufacturer and then carry out the fitting. This could ensure the best possible quality and the lowest cost of labour.
It’s worth keeping track of your catalytic converter’s condition. Your vehicle will struggle without a healthy cat, and you could end up forking out expensive repair bills if it breaks down.
If you think your vehicle’s catalytic converter needs to be looked at by a professional mechanic, find a local garage near you using our online booking tool. It’s quick, easy, available 24/7 and, most importantly, free to use. All you need to do is enter your registration number to find a list of garages local to you.