Is Your Exhaust Blowing? Signs, Causes and Why It Matters

What a blowing exhaust sounds like

When people say their exhaust is blowing, they mean gas is escaping somewhere before it reaches the tailpipe. The most obvious sign is noise. The car sounds louder or rougher than it used to, often with a deep rumble when you pull away.

A small leak near the engine can make a quick ticking or puffing sound that speeds up as the revs rise. It is often worst when the engine is cold and quietens as the metal warms up and expands, which is why some people only hear it first thing in the morning.

Where exhausts usually go wrong

Rust is the main enemy. Every time you start the car, water forms inside the exhaust as the engine burns fuel. On a long drive the system gets hot enough to dry it out, but lots of short trips leave that water sitting inside, and the exhaust slowly rusts from the inside out.

Other common weak spots are the flexible joint near the front, which lets the engine move without cracking the pipe, the gaskets where sections join, and the rubber hangers that hold the system up. A broken hanger lets the exhaust drop and knock against the underside of the car.

Damage plays a part too. Speed bumps, kerbs and potholes can dent or split a pipe, particularly on lower cars.

Why you should not ignore it

Exhaust gas contains carbon monoxide, which you cannot see or smell and which is dangerous to breathe. A leak under the car can let fumes find their way into the cabin, especially when you are sitting in traffic. If you ever smell exhaust inside the car, or feel drowsy or get a headache while driving, open the windows and get it checked straight away.

A leak can also upset the sensors that measure the exhaust gas, which can bring on the engine warning light, make the car run less smoothly and use more fuel.

A blowing exhaust is also tiring to live with. The extra drone on the motorway and the rattle as you pull up outside the house are easy to get used to, but they usually mean the leak is slowly getting bigger, and a small repair today can turn into a larger one later.

Exhausts and your MOT

Your exhaust is checked at every MOT. A leaking system, a missing or insecure part, or a car that is too noisy can all be a fail. The tester also measures what comes out of the tailpipe, and a leak can affect that reading.

If your exhaust has started blowing and your MOT is coming up, it is worth having it looked at first. It saves a fail, and gives you time to decide what to do without rushing.

Repair or replace?

Not every blow means a whole new exhaust. Sometimes a new gasket, clamp or hanger is all it needs. If one section has rusted through, we can often replace just that part. We only suggest a larger job when the pipes around it are too far gone to hold a repair.

A rattle from under the car is not always the pipes either. A loose heat shield is a common cause and is often a quick fix. A rattle from inside the catalytic converter is a different matter, and we will explain the options if that is what we find.

Book an exhaust check in Walsall

We put your car on the ramp, find exactly where it is blowing and show you. Then we give you a clear quote before any work starts, with the cheapest sensible fix first.

Call us on 01922 682200 or book online, and pop into 45 High Street, Pelsall. We will have you sounding quiet again.