MOT defects · Engine, exhaust and leaks

Exhaust leak MOT advisory: what it means and which cars get it

In DVSA MOT data for 2023, analysed by RegTail, testers recorded this as an advisory on at least 1.6 in 100 and as a failure on at least 0.5 in 100 initial MOT tests. The Volkswagen Fox got it most often: recorded 15.8 times per 100 of its 28,542 tests.

DVSA wording: Exhaust system leaking or insecure.

Failures

0.5 in 100

At least 158,807 tests in 2023

Advisories

1.6 in 100

At least 528,204 tests in 2023

Most often

Volkswagen Fox

15.8 per 100 tests

What it means

Exhaust gas is escaping before the tailpipe, or part of the system is loose. Common causes are a rusted pipe or silencer, a failed joint or a broken mounting rubber. As an advisory it usually reads "minor leak of exhaust gases".

How serious it is

A major defect, so a fail, when there is a major leak or the system is insecure. Fumes entering the cabin are a fail too.

Source: MOT inspection manual for cars and light vans, section 6.1.2.

Major Fail
It may affect the vehicle's safety, put other road users at risk or have an impact on the environment. Repair it immediately.
Advisory Pass
It could become more serious in the future. Monitor and repair it if necessary.

What fixing it usually involves

A new section, joint or mounting rubber. Manifold and flexi-pipe leaks near the engine take longer.

A general guide, not a quote: ask a garage to inspect the car.

Which models get it most

Per 100 initial MOT tests on each model, among the 137 models with at least 20,000 tests where it is among the 40 most common items. DVSA MOT data for 2023, analysed by RegTail.

Model	Tests	Fail	Advisory
Volkswagen Fox	28,542	5.4	10.4
Fiat Punto	72,390	4.3	9.4
Hyundai Getz	23,077	4.0	7.9
Vauxhall Zafira	229,031	2.5	7.2
Saab 9-3	43,277	2.3	6.9
Vauxhall Vectra	39,116	3.0	5.2
Vauxhall Astra	704,979	2.1	5.5
Mitsubishi Shogun	35,550	2.8	4.3
Peugeot 206	58,647	4.7	2.3
Isuzu D-Max	35,425	3.0	3.8

What to check at a viewing

On the car
Start the engine from cold and listen at the tailpipe and underneath for blowing or ticking. Look for black soot around joints and for sagging sections.
In the MOT history
If this appears as an advisory, see whether it came back at the next test or turned into a failure, and ask the seller for the receipt if it was fixed.

Check a specific car

Fleet averages only go so far. Enter the registration to see that car's own MOT history, mileage record and current condition, free.

Questions

What does "Exhaust leak" mean on an MOT?

Exhaust leak: is it an MOT fail?

A major defect, so a fail, when there is a major leak or the system is insecure. Fumes entering the cabin are a fail too.

Which cars are most likely to get "exhaust leak" on an MOT?

In DVSA MOT data for 2023, analysed by RegTail, the models that got it most often were the Volkswagen Fox (15.8 per 100 tests), the Fiat Punto (13.7 per 100 tests), the Hyundai Getz (12.0 per 100 tests).

More engine, exhaust and leaks defects

See every MOT defect we explain or MOT pass rates by model.

Oil leak Gearbox oil leak Exhaust leak Engine warning light on Lambda reading out of limits Airbag warning light on

How these figures are made. We counted the defects recorded at every initial MOT test (not retests) of cars and light vans in Great Britain in 2023 in the DVSA anonymised MOT dataset, 33,842,940 tests in all. Each item counts once per test. A failure is a major or dangerous defect, including one fixed during the test. A model's rate is the share of its tests where the item was recorded.

For each model we keep its 40 most frequent items, so a model where a defect is rarer than that is not listed, and figures for all cars are a floor. Defect names and explanations are ours, checked against the MOT inspection manual; DVSA's own wording is shown under each name.

Contains public sector information licensed under the Open Government Licence v3.0. RegTail's analysis of the DVSA anonymised MOT dataset, 2023 tests.