Common exhaust faults
Exhaust systems corrode from the inside out, and the first sign is usually noise rather than a visible hole:
- A blowing or rasping sound, often loudest when cold or under acceleration
- Rattling over bumps, usually a failed bracket or heat shield
- Reduced power and poorer fuel economy from a blocked or collapsed section
- A hissing or ticking near the manifold or flexi-pipe
- The engine management light on diesel vehicles, often caused by a blocked DPF or a faulty sensor rather than the pipework itself
Exhausts and the MOT
The MOT checks the whole system for security, leaks and excessive corrosion, and tests emissions. A leak before the catalytic converter can fail on emissions even if the pipe looks fine, and a missing or insecure heat shield can fail too.
Diesel particulate filters must be present and functioning where they were fitted as standard. Removing one is an automatic failure, and it is also an offence on the road.
Repair or replace?
An exhaust is a series of sections: front pipe with the catalytic converter, centre section, back box, plus hangers and gaskets. A hole in one section usually means replacing that section rather than the whole system, though on older cars the next section often follows within a year.
Stainless steel and aftermarket systems last considerably longer than mild steel originals, which is worth considering if you intend to keep the car.
Booking an exhaust repair in Liverpool
Ask the garage to show you the failed section or send a photo before work starts, and confirm whether clamps, gaskets and hangers are included in the quote.