How reliable is the Ford Sierra compared with other cars?

We do not publish a comparison for the Ford Sierra, because the cars of this model that have been tested do not cover a wide enough range of ages and mileages. Its raw pass rate is 87.6% across 2,192 tests, but comparing a raw rate between models mostly ranks them by how new they are rather than how good they are. The failure and advisory patterns further down the page are still drawn from real tests and are worth reading.

What do testers most often warn about on a Ford Sierra?

The most common advisory is "Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users", noted on 7.2% of all Ford Sierra tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a Ford Sierra usually have at its MOT?

The average odometer reading recorded at test is 52,065 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.

Are most Ford Sierra models petrol or diesel?

Of the Ford Sierra cars tested, 98% are petrol, 2% are diesel. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

Model reliability file

Ford Sierra MOT pass rate & common failures

From 2,192 recorded MOT tests of the Ford Sierra, published by DVSA.

Data updated 29 July 2026

Quick answer

Across 2,192 MOT tests, 87.6% of Ford Sierra tests ended in a pass. This figure is not adjusted for age or mileage, so it is not a reliability ranking: the Ford Sierra fleet does not yet cover a wide enough spread of ages and distances to compare it fairly against other models. Its most commonly recorded failure is strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired, which appears in 21.4% of failed tests. Cars of this model average 52,065 miles on the odometer when tested.

At a glance

Recorded pass rate

87.6%unadjusted, not comparable2,192 tests

We are not publishing a ranking for the Sierra. The examples tested do not cover a wide enough spread of ages and mileages to compare it fairly, and an unadjusted pass rate mostly sorts models by how recently they were bought rather than how well they were built. The failure and advisory patterns below come from the same 2,192 tests and are worth reading on their own terms.

DVSA recorded wording

Most common failure items

Share of failed Ford Sierra tests in which each item was recorded. One failed test often lists several items, so these do not sum to 100%.

1.The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired21.4%
48 occurrencesSuspension mounting corroded or insecure explained
2.The strength or continuity of the load bearing structure within 30cm of any seat belt anchorage (a 'prescribed area') is significantly reduced or inadequately repaired10.7%
24 occurrencesSeat belt anchorage corroded or weakened explained
3.Emissions levels exceed default limits10.7%
24 occurrencesEmissions above the permitted limit explained
4.Vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced9.8%
22 occurrencesCorrosion in a structural area explained
5.Wiper blade missing or obviously not clearing the windscreen8.0%
18 occurrencesWiper or washer not working properly explained
6.Steering rack gaiter or ball joint dust cover missing or no longer prevents the ingress of dirt etc7.6%
17 occurrencesSteering rack gaiter split, damaged or missing explained
7.A transmission shaft constant velocity joint boot missing or no longer prevents the ingress of dirt etc7.1%
16 occurrencesDriveshaft CV joint gaiter split or missing explained
8.Brake pipe damaged or excessively corroded7.1%
16 occurrencesBrake pipe corroded explained
9.A suspension pin, bush or joint excessively worn7.1%
16 occurrencesSuspension arm bush worn explained
10.The aim of a headlamp is not within limits laid down in the requirements6.7%
15 occurrencesHeadlamp aim incorrect explained

Warnings without a failure

Most common advisories

Share of all Ford Sierra tests carrying each advisory. The denominator differs from the failure list above because an advisory can be issued on a car that passed.

1.Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users7.2%
157 tests
2.A tyre seriously damaged4.8%
105 testsTyre damaged or deteriorated explained
3.Brake pipe damaged or excessively corroded4.2%
91 testsBrake pipe corroded explained
4.A spring or spring component fractured or seriously weakened3.2%
70 testsRoad spring broken or fractured explained
5.Tyre tread depth not in accordance with the requirements3.1%
69 testsTyre worn close to the legal limit explained
6.Brake disc or drum excessively weakened, insecure or fractured2.7%
60 testsBrake disc worn, pitted or scored explained
7.The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired2.7%
59 testsSuspension mounting corroded or insecure explained
8.A suspension pin, bush or joint excessively worn2.5%
55 testsSuspension arm bush worn explained

The rest of the record

Everything else recorded on the Ford Sierra

The 16 other defects testers recorded on this model, beyond the most common listed above. Each links to what it means and what it takes to put right.

What gets tested

The Sierra fleet

Average mileage recorded at test: 52,065
Fuel mix of tested cars: Petrol98.1%
Diesel1.8%

Check a specific Ford Sierra

A model average tells you the pattern. Its own MOT record tells you the car.

Compare within the range

Other Ford models

Ford Fiesta — 67.1% adjusted
Ford Focus — 71.6% adjusted
Ford Kuga — 75.3% adjusted
Ford Transit — 68.0% adjusted
Ford Transit Custom — 77.3% unadjusted
Ford Mondeo — 76.0% adjusted
All Ford models

Common questions

How reliable is the Ford Sierra compared with other cars?: We do not publish a comparison for the Ford Sierra, because the cars of this model that have been tested do not cover a wide enough range of ages and mileages. Its raw pass rate is 87.6% across 2,192 tests, but comparing a raw rate between models mostly ranks them by how new they are rather than how good they are. The failure and advisory patterns further down the page are still drawn from real tests and are worth reading.
What is the most common MOT failure on a Ford Sierra?: The item recorded most often is "The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired", which appears in 21.4% of failed Ford Sierra tests. Because one failed test can list several items, these shares do not add up to 100%.
What do testers most often warn about on a Ford Sierra?: The most common advisory is "Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users", noted on 7.2% of all Ford Sierra tests. An advisory is not a failure: it flags something that will likely need attention before the next test.
What mileage does a Ford Sierra usually have at its MOT?: The average odometer reading recorded at test is 52,065 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.
Are most Ford Sierra models petrol or diesel?: Of the Ford Sierra cars tested, 98% are petrol, 2% are diesel. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

How this was worked out

Method and limits

Figures come from the DVSA anonymised MOT testing dataset, published under the Open Government Licence. Only class 4 initial tests are counted: retests are excluded so a car appears once, and abandoned tests are excluded entirely. No adjusted rate is shown because this model's tested examples do not cover enough of the national age and mileage range for standardisation to mean anything.

An MOT measures whether a car met a legal standard on the day. It is not a breakdown record, a service history or a running-cost estimate, and a pass rate is a property of a fleet rather than a prediction about one car.