White powder

There is white powder coming out of my exhaust – should I be worried?

• A sure sign of catalytic converter failure

• Will require a catalytic converter replacement

• Leaving problem could result in MOT failure

In a word, yes. It probably means your catalytic converter is breaking-up, while this won’t damage your car too much if you drive a short distance, it will need replacing quickly to avoid further engine issues occurring.

The Catalytic Converter (CAT) is often made of ceramic material, the whitish powder you see coming out of the exhaust means the internal strata within the CAT has fractured. Consequently, your CAT will not be reacting the toxic gases produced by the combustion process, increasing emissions.

What can cause this type of CAT failure?

This can be caused by a number of issues, but usually it is an impact that has caused the ceramic brick to break-up. Anything from stones to speed calming humps can do this over the course of regular use. It won’t damage your car if you drive it to the garage, but it will need replacing.

What is the impact on the environment?

A compromised CAT places your vehicle at risk of failure during the MOT test, as the emissions from your vehicles will contain more toxic gases such as Carbon Monoxide, Nitrogen Oxides and Hydrogen Carbons. Usually, these gases are reacted inside the CAT to produce less harmful Nitrogen, Water and Carbon Dioxide. By operating a vehicle with a faulty CAT over the long term, you risk increasing your impact on the environment, as well as the vehicles original environmental credentials and legislative compliancy.

Repair or Replacement?

As the CAT is a premium component in the exhaust assembly, a damaged internal strata will require a total replacement rather than repair. This will ensure that the car is not hindered by a defective device, offering the efficiency levels expected of the vehicle when it was new.