How does an exhaust work?
An exhaust system has the primary function of guiding fumes away from a controlled combustion section of an engine. The exhaust system on a car is carefully designed so the fumes omitted from the engine can be safely transported away from passengers in the car.
The exhaust system is made up of a several parts, all of which could cause potential issues if damaged. Though you only see the tail pipe from the outside of the car, the exhaust system is a large system.
The exhaust ensures fumes are transported from the engine all the way to the tailpipe at the back of the car. The gas flows down from the engine to the flange and onto the catalytic converter, it then travels on to the muffler and resonance chamber before going to the resonator and finally out through the tailpipe.
All of these parts have distinctive functions with piping connecting them along the bottom of the car. Each section of the system has to be completely airtight and functioning properly to ensure the gases are released into the outside environment safely.
Because there are several components of the exhaust system and because it usually stretches the full length of the car, costs can vary.
Depending on the area, part and extent of the damage, you are likely to pay different prices. Some repairs may only consist of sealing a small leak whereas others may result in replacing entire pipes or elements.
How does the exhaust affect performance?
If there is a leak in the exhaust system, there is a chance that engine performance will be negatively affected. This is due to the escape of pressure at the wrong point of the system.
Are Exhaust leaks dangerous?
It is essential that an exhaust system is not damaged as leakage could pose danger to those inside the vehicle. Hydrocarbons, carbon monoxide and nitrogen oxides could seep into a car if the exhaust is damaged. These gases are also extremely hot and would cause serious damage if they were to meet a passenger.
The piping in an exhaust system must be heat resistant due to the high temperatures of these compounds and if the exhausts integrity is compromised, anything close to the damaged area will be exposed to potential harm.
If your DPF is also blocked or not functioning properly, soot and particulate will escape from the system and cause damage to the environment and people in the surrounding area.
Can an exhaust leak cause low oil pressure?
If there is an oil leak, there is only a very small chance that the problem is the exhaust system. This is due to the fact that engine oil doesn’t course through the exhaust like it does for a part like the head gasket.
However, if there is an oil leak, it may get into the combustion system and the result will be blue smoke coming from the exhaust.
Can an exhaust leak cause the check engine light to come on?
A warning light will come on but it will not likely be the check engine light. This is because a problem with the exhaust will be detected specifically by oxygen sensors or the sensors in the DPF if your exhaust system is fitted with one.
Signs that your Exhaust needs repairing or replacing
Exhaust is loud
A common symptom for a damaged exhaust is a loud roaring noise being emitted from your vehicle. This noise would indicate that you have a problem with the silencer part of the system. A common issue with silencers is corrosion by acidic moisture which is caused by a build-up of the damaging substance.
Exhaust is leaking
If a part of the system has cracked or a hole has appeared, you will be able to hear a hissing noise and a chugging sound could mean there is a blockage in the system. If the exhaust is leaking, the issue needs to be addressed immediately as the fumes are dangerous.
Exhaust is leaking water
There is also a chance that the exhaust is leaking water, in which case, there is a crack or hole somewhere in the system as a possible result of a water leak from the head gasket.
Exhaust is popping
If you hear the exhaust popping or rattling beneath your car it could mean that your exhaust has become misaligned and if you can hear a loud metallic vibration it usually means that something is hitting the exhaust pipe. It could also mean a clamp, mounting or support bracket exhaust is loose.
Exhaust is loose
Hangers and brackets are essential for holding the system in place so if these parts become damaged there is a significant risk that the rest of the system will suffer damage as a result.
If you are able to get underneath your car, it is always the best way to check for signs of damage.
Exhaust is rusty
One of the most common issues associated with exhausts is rust build up, however this can often be a minor issue as some pealing of metal is not a huge issue.
If there is a build-up of rust on any part of the system, use a tool such as a screwdriver to see how strong the area feels, if the integrity is solid then the part won’t need replacing however if the metal feels weak when some pressure is applied, its time you get the part removed and a new one installed.
Exhaust is smoking
Black Smoke from Exhaust
Black smoke coming from your exhaust means that your engine is burning more fuel than it should. This is often caused by a problem with your fuel injectors, air filter or fuel-pressure regulator. Alternatively, the fuel line could be clogged. Burning excessive fuel will have a noticeable effect on fuel economy meaning that you will be spending much more money getting from A-B.
Blue Smoke from Exhaust
If your exhaust in pumping out blue smoke, oil will have leaked into the engine and been burned in the system. This happens following the valve guide seals or piston rings wearing out and allowing engine oil into the combustion chamber. Engine oil is only meant for the lubrication of parts which are in constant contact with each other.
If engine oil is leaking into the combustion system, you need to have the issue addressed with an oil changeimmediately as low engine oil levels will be incredibly detrimental to your car.
White Smoke from Exhaust
If white smoke is coming from your exhaust, your car could be low on engine coolant from the result of a cracked or warped cylinder head, a cracked engine block or a head gasket failure from overheating.
If engine coolant gets anywhere near the combustion chamber, the liquid will be vaporised and converted into a white gas which is then pushed out through the tailpipe.
If the exhaust is smoking thick black, white or blue fumes, there is also an issue with the system as the exhaust should not be blowing this colour of smoke. To find out why your exhaust is blowing smoke use our dedicated guide.
The catalytic converter is the part of the exhaust system that converts the dangerous fumes produced by a car engine, into a safer gas which can be pushed into the air. The catalytic converter is an expensive part of the exhaust system as it is a complex piece of machinery and repairing it can be complicated. For the same reason, replacing a catalytic converter is also expensive. If there is a small amount of rust on the catalytic converter this can be repaired relatively simply, and even a small hole can be fixed with some welding, however, you will have to go by your mechanics advice as once a hole is too big, it cannot be welded shut.
The exhaust manifold is the piping that takes the fumes from the catalytic converter and out to the tailpipe which is also part of the manifold. This part can often become loose and rattle from the result of the fittings breaking from extensive rusting. The part can also leak fumes if holes appear, though they can be welded shut. The exhaust manifold should not be too expensive to repair if there is a small hole, but if you need a new exhaust manifold, the price may be quite high depending on the car model.
The lambda sensor is an oxygen monitor located within the exhaust system. It is critical to keep track of oxygen levels within the exhaust as too much could cause an explosion if it reaches the engine. Getting a new lambda sensor is an inexpensive job and fitting it should not take too long, however, the only way to make sure is by getting a personal quote from a trained technician from WhoCanFixMyCar to fit a new Lambda Sensor. If you ask for a new oxygen monitor or if the mechanic tells you that you need a new oxygen sensor in the exhaust system, this is the same thing.
Exhaust repair cost
Car exhaust repair is a service which can be priced at a variety of levels. This is due to the fact that there are a number of things which could go wrong. For example, exhaust hole repair will vary as the size of the damage will be unique to your car and so the cost of exhaust replacement or exhaust pipe repair cannot be predicted, you simply need to get a personal quote from local garages using WhoCanFixMyCar!
Who installs and repairs exhaust systems?
Trained mechanics working in independent garages, fast fit chains and main dealerships can deliver exhaust repair and new exhaust installation. You can find the best local exhaust specialists by requesting quotes from WhoCanFixMyCar.
We work with a network of 17,206 mechanics and garages across the UK so we can find competitive exhaust repair deals for you.
To find the best exhaust service available, follow these steps;
- Enter your car registration number
- Give us a few details about your car and your requirements
- We’ll send you a great selection of quotes from mechanics and garages in your area
You can then compare the quotes and read reviews from previous customers to find the best exhaust deal in your area, before booking the exhaust repair online.
Debs from Foxley Garage explains the Exhausts system