The exhaust system does three jobs. It removes combustion gases safely away from the engine and occupants. It reduces the noise the engine produces to a level that passes the MOT. It treats the exhaust gases through the catalytic converter and, on diesels, the DPF to reduce harmful emissions. A failing exhaust compromises all three at once. At KITH Cars Garage in Hackbridge, we carry out exhaust repairs across all makes and models.
Noise is normally the first thing customers notice. A sudden ticking or blowing sound, loudest on cold start and under acceleration, means there is a hole or crack somewhere in the system. The location of the noise gives a rough indication of which section is affected. Noise from behind the passenger cabin is usually the rear silencer or back box. Noise closer to the engine suggests the manifold, flexi pipe or catalyst section.
Exhaust corrosion is what fails most systems on older vehicles. Road salt, water and the constant heat cycling from driving corrode mild steel from the outside in. We probe the metal around any corrosion to assess how extensive it is before recommending a repair or replacement. A small patch job on a section that is heavily corroded elsewhere is money spent poorly.
Flexi pipes are worth knowing about if you drive a diesel with higher mileage. They are short corrugated metal sections, usually near the front of the exhaust close to the engine, that accommodate the movement between the engine mounts and the fixed exhaust system. They crack with age and are a very common source of exhaust noise on diesel vehicles over 80,000 miles. They are not listed as a standard exhaust section in most parts catalogues but we stock and fit them regularly.
Lambda sensors are charged at our top rate of £84/hr because they are classified as sensor replacement work. The pre-cat sensor provides constant feedback to the engine management system about the fuel-air mixture. When it fails, the engine runs rich, economy drops, and an engine management light appears. We always read the fault codes before recommending sensor replacement to confirm which one has failed and rule out wiring issues.
Catalytic converter pricing ranges enormously depending on the vehicle. A standard cat for a family hatchback is relatively inexpensive. A cat for a hybrid or a premium vehicle with multiple sensors can be several hundred pounds in parts alone. We live-price every catalytic converter job before providing a quote and always get written approval before parts are ordered.
