Problems of the exhaust: symptoms, cost and affected models
We have documented 13 faults of the exhaust in 4 engines and 9 cars, affecting 39 models of car in our database. The most important by severity and frequency: cylinder head and valve damage from exhaust gas backflow (Volkswagen Polo IV) (1.2 12V), cracked weld between the rear silencer and the exhaust tailpipe (Mitsubishi ASX I) and cracked exhaust manifold (2.2 i-CTDi and BMW M57).
How it works and why it fails
Exhaust and silencers
The exhaust system carries the engine gases to the tailpipe, passing through the catalytic converter, the particulate filter on diesels and the silencers. Gaskets, hangers and the sections most exposed to damp and road salt are the first to fail.
What to do
A louder than normal noise, a clunk under the car or a smell of exhaust fumes in the cabin points to a leak or a broken hanger. Do not leave it: a leak before the lambda sensor skews the mixture, and exhaust gases getting into the car are dangerous.
General explanation by MotorFiable. The specific faults of each engine and car, with their sources, are on the linked pages.
Common symptoms
The symptoms that come up most often in the documented faults of the exhaust. Open each one to see what other faults cause it.
Problems of the exhaust by engine
From most to least important (severity × frequency). Each page details the affected versions and years, symptoms, cost and how to check for it.
- 1High severityFrequency: Occasional1.2 12VCylinder head and valve damage from exhaust gas backflow (Volkswagen Polo IV)On the Volkswagen Polo IV, the catalytic converter is very close to the cylinder head; when you lift off the accelerator, exhaust gases can flow back towards the engine and damage or burn the cylinder head and exhaust valves. It is a documented design fault, not ordinary wear.Appears at around 24,000 km
- 2Medium severityFrequency: Common2.2 i-CTDiCracked exhaust manifoldYes: the 2.2 i-CTDi's exhaust manifold can crack with mileage, especially on the Civic and Accord, with cases documented between 100,000 and 200,000 km; Honda covered at least one case under its manufacturer's warranty.Appears at around 100,000 km
- 3Medium severityFrequency: OccasionalBMW M57Cracked exhaust manifoldThe M57 exhaust manifold can crack, causing loss of power, an unstable idle and a smell of exhaust fumes in the cabin; the recommended repair is to replace it with a cast one.
- 4Low severityFrequency: Rare1.0 VVT-iHead gasket and exhaust gasket: no documented patternThe head gasket does not appear as a relevant problem on the 1.0 VVT-i either: between 0 and 2 cases out of more than 200 reviews on the C1 and 107/108, and it does not even appear as a category of its own in the Aygo data consulted.
Engines with faults of the exhaust
Problems of the exhaust by car
Faults documented on specific cars, which occur with any engine. From most to least important.
- 1High severityFrequency: OccasionalMitsubishi ASX ICracked weld between the rear silencer and the exhaust tailpipeMitsubishi has recalled the ASX twice over a cracked weld between the rear silencer and the tailpipe: in 2018 (ASX GA1W of 2011-2018) and in 2025 (4A92 engine, built between June 2010 and June 2019). The pipe can come loose and fall onto the road.
- 2Medium severityFrequency: OccasionalOpel SignumRear exhaust clamp allows the pipe to come off the front one (2004 recall)In November 2004 Vauxhall (Opel) recalled 10,470 vehicles in the UK (a figure repeated for Signum and Vectra) because the rear exhaust pipe could slide backwards and come off the front one, risking damage to underbody parts. The underbody is checked and a new clamp is fitted.
- 3Medium severityFrequency: OccasionalVolvo S40 IIChrome exhaust pipe trim coming off on 2010-2011 Volvo S40sYes: Safety Gate (alert A12/0254/14, February 2014) warns that on the 2010 and 2011 S40 and V50 a chrome element at the end of the exhaust pipe can work loose and fall onto the road. The Spanish press (Autofácil) reported it in March 2014.
- 4Medium severityFrequency: OccasionalVolvo V50Chrome exhaust pipe trim coming off on 2010-2011 Volvo V50sYes: Safety Gate (alert A12/0254/14, February 2014) warns that on the 2010 and 2011 S40 and V50 a chrome element at the end of the exhaust pipe can work loose and fall onto the road. The Spanish press (Autofácil) reported it in March 2014.
- 5High severityFrequency: RareFord Fiesta VII2011 recall for possible exhaust fumes entering the cabinFord recalled Fiestas built between July and November 2011 because they could suffer exhaust fumes entering the cabin. It is a campaign limited to that production period, not a problem across the whole generation.
- 6Low severityFrequency: OccasionalFiat Panda IIExhaust and underbody corrosion on the Fiat Panda IIFiches-auto.fr reports corrosion cases, mainly of the exhaust silencer, and the 2025 TÜV report cited by Autoblog.it describes it as a persistent problem on older Panda 169s.
- 7Low severityFrequency: OccasionalNissan Juke IRear silencer rusts and perforatesGebrauchtwagenberater.de says the Juke's intermediate exhaust silencer often ends up pitted by rust, and recommends checking the underbody before buying a used one.
- 8Low severityFrequency: OccasionalSeat MiiExhaust corrosion on the Seat Mii in town drivingGerman guides cite exhaust corrosion on the Mii as a weak point when the car makes short journeys and never gets warm, and the TÜV flags it more as the years pass.
- 9Low severityFrequency: OccasionalŠkoda CitigoExhaust corrosion on the Skoda Citigo in town drivingThe ADAC cites an exhaust prone to failure, mainly on the first Citigo units, and German guides put it down to short urban journeys.
Frequently asked questions
Which engines have the most faults of the exhaust?
By severity and frequency, the 1.2 12V (cylinder head and valve damage from exhaust gas backflow (Volkswagen Polo IV), high severity), the 2.2 i-CTDi (cracked exhaust manifold, medium severity), the BMW M57 (cracked exhaust manifold, medium severity) and the 1.0 VVT-i (head gasket and exhaust gasket: no documented pattern, low severity).
Which cars have problems of the exhaust?
Among those we have analysed: Mitsubishi ASX I (cracked weld between the rear silencer and the exhaust tailpipe), Opel Signum (rear exhaust clamp allows the pipe to come off the front one (2004 recall)), Volvo S40 II (chrome exhaust pipe trim coming off on 2010-2011 Volvo S40s), Volvo V50 (chrome exhaust pipe trim coming off on 2010-2011 Volvo V50s), Ford Fiesta VII (2011 recall for possible exhaust fumes entering the cabin), Fiat Panda II (exhaust and underbody corrosion on the Fiat Panda II), Nissan Juke I (rear silencer rusts and perforates) and Seat Mii (exhaust corrosion on the Seat Mii in town driving). In total, 9 cars with documented faults of the exhaust.
What symptoms does a fault of the exhaust cause?
The most frequently cited in the documented faults: gradual loss of power, smell of exhaust fumes inside the cabin, rust or corrosion on the bodywork or underside, engine fault warning light (check engine), burning smell and persistent, dense white smoke.