Is the Porsche Cayman reliable?

On MOT evidence the Porsche Cayman is well above average. It passes 87.2% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 84% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.

What is the most common MOT failure on a Porsche Cayman?

The item recorded most often is "Tyre tread depth not in accordance with the requirements", which appears in 18.4% of failed Porsche Cayman 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 Porsche Cayman?

The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 13.1% of all Porsche Cayman tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a Porsche Cayman usually have at its MOT?

The average odometer reading recorded at test is 50,808 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.

Does a Porsche Cayman get harder to pass as it ages?

Yes. At 3 to 5 years old, 94.9% of Porsche Cayman tests pass. By fifteen years or more, that falls to 81.3%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.

Model reliability file

Porsche Cayman MOT pass rate & common failures

From 14,702 recorded MOT tests of the Porsche Cayman, published by DVSA.

Data updated 29 July 2026

Quick answer

The Porsche Cayman passes 87.2% of MOT tests once results are adjusted for the age and mileage of the cars tested, against a national average of 72.3%. That is well above average. Based on 14,702 tests. Its most commonly recorded failure is tyre tread depth not in accordance with the requirements, which appears in 18.4% of failed tests. Cars of this model average 50,808 miles on the odometer when tested.

At a glance

Pass rate, adjusted for age and mileage

87.2%national average72.3%unadjusted88.9%range covered84%

The Cayman is 14.9 percentage points above the national pass rate once age and mileage are accounted for, which is well above average. The unadjusted figure is 88.9%; the difference is what the age and mileage of this model’s fleet was hiding.

DVSA recorded wording

Most common failure items

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

1.Tyre tread depth not in accordance with the requirements18.4%
255 occurrencesTyre worn close to the legal limit explained
2.Brake pipe damaged or excessively corroded13.3%
185 occurrencesBrake pipe corroded explained
3.A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning12.8%
178 occurrencesLamp not working explained
4.Lambda coefficient outside the default limits or the range specified by the manufacturer10.0%
139 occurrencesEmissions above the permitted limit explained
5.A spring or spring component fractured or seriously weakened9.8%
136 occurrencesRoad spring broken or fractured explained
6.A tyre seriously damaged7.4%
103 occurrencesTyre damaged or deteriorated explained
7.A suspension pin, bush or joint excessively worn5.8%
80 occurrencesSuspension arm bush worn explained
8.Wiper blade missing or obviously not clearing the windscreen5.8%
80 occurrencesWiper or washer not working properly explained
9.The aim of a headlamp is not within limits laid down in the requirements5.7%
79 occurrencesHeadlamp aim incorrect explained
10.A tyre cords visible or damaged4.8%
66 occurrencesTyre ply or cord exposed, or the casing separating explained

Warnings without a failure

Most common advisories

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

1.Tyre tread depth not in accordance with the requirements13.1%
1,926 testsTyre worn close to the legal limit explained
2.A tyre seriously damaged11.2%
1,648 testsTyre damaged or deteriorated explained
3.Brake pipe damaged or excessively corroded11.2%
1,643 testsBrake pipe corroded explained
4.Brake disc or drum excessively weakened, insecure or fractured10.5%
1,542 testsBrake disc worn, pitted or scored explained
5.A suspension pin, bush or joint excessively worn2.1%
307 testsSuspension arm bush worn explained
6.Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users2.0%
301 tests
7.Nail in tyre1.9%
285 tests
8.Play in steering rack inner joint(s)1.9%
279 tests

How wear changes the picture

Pass rate by vehicle age

3–5 yrs95%

6–8 yrs94%

9–11 yrs93%

12–14 yrs90%

15+ yrs81%

Bands holding too few tests to be meaningful are omitted rather than shown as a rate.

What gets tested

The Cayman fleet

Average mileage recorded at test: 50,808
Fuel mix of tested cars: Petrol100.0%

Trim names grouped into this model (10)

Recorded exactly as DVSA holds them. Trim-level names are rolled up so one model is not split across a dozen thin pages.

CAYMAN GTS
CAYMAN R
CAYMAN R S-A
CAYMAN S
CAYMAN S BLACK EDITION S-A
CAYMAN S S-A
CAYMAN S TIPTRONIC S
CAYMAN S-A
CAYMAN T
CAYMAN TIPTRONIC S

Check a specific Porsche Cayman

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

Compare within the range

Other Porsche models

Porsche 911 — 89.5% adjusted
Porsche Macan — 89.5% adjusted
Porsche Boxster — 85.7% adjusted
Porsche Cayenne — 85.3% adjusted
Porsche Taycan — 91.0% unadjusted
Porsche Panamera — 87.8% adjusted
All Porsche models

Similar test volumes

Compare against other makes

Bentley Continental — 90.7% adjusted, ranked 1
Citroen Relay — 68.6% adjusted, ranked 188
Subaru Forester — 75.1% adjusted, ranked 110
Dacia Logan — 72.6% adjusted, ranked 136

Common questions

Is the Porsche Cayman reliable?: On MOT evidence the Porsche Cayman is well above average. It passes 87.2% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 84% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.
What is the most common MOT failure on a Porsche Cayman?: The item recorded most often is "Tyre tread depth not in accordance with the requirements", which appears in 18.4% of failed Porsche Cayman 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 Porsche Cayman?: The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 13.1% of all Porsche Cayman tests. An advisory is not a failure: it flags something that will likely need attention before the next test.
What mileage does a Porsche Cayman usually have at its MOT?: The average odometer reading recorded at test is 50,808 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.
Does a Porsche Cayman get harder to pass as it ages?: Yes. At 3 to 5 years old, 94.9% of Porsche Cayman tests pass. By fifteen years or more, that falls to 81.3%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.

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. The adjusted rate is directly standardised across twenty-five age and mileage bands and reweighted onto the national distribution, so this model is compared against cars that have lived a similar life rather than against a younger or lighter-used fleet.

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.