Mazda RX-8 2004: MOT failure rate for its age

35.7% of 3,439 MOT tests of the Mazda RX-8 first registered in 2004 failed at the first attempt (2019–2024; retests excluded). Against this model's own normal rate at the same ages the index is 104.8 (95% CI 99.0–110.7; 100 = normal for this model at that age): the 2004 build year is no different from other years of the same model at the same age. This is a rough estimate from a smaller sample.

Mazda RX-8 built in 2004 at a glance
Measure	Value	Unit	Compared with	Years	Tests
Failed first time	35.7	%	all ages tested	2019–2024	3439
Index against this model at the same age (95% CI 99.0–110.7)	104.8	index	100 = normal for this model at that age	2019–2024	3439
Rank among this model's 8 build years	7	of 8	1 = fails least for its age	2019–2024	3439
Tested in 2024	488	tests	median 66,186 miles	2024	488

Built 2004 against Mazda RX-8 normal for the age: first-time MOT failure share at each age, age 16: 39.5% vs 35.8%; age 17: 36.5% vs 34.9%; age 18: 33.1% vs 33.4%; age 19: 33.4% vs 32.5%; age 20: 33.4% vs 32.3%. Axis from 0% to 40%. DVSA MOT bulk data, 2019–2024.

Check a 2004 Mazda RX-8 by registration · All Mazda RX-8 MOT statistics · Download the build-year table (CSV)

Data release dvsa-2024-v2 (24 Sep 2026) · page updated 30 Sep 2026 · full dataset (v5).

How does the 2004 Mazda RX-8 fail at each age?

Cars built in 2004 were tested at ages 16 to 20 between 2019 and 2024. Each row compares their first-time failure share with what this model normally shows at that age, after allowing for the overall failure level of each test year.

Mazda RX-8 built 2004: first-time MOT failure by age, against the model's normal rate at that age (2019–2024)
Age	Tests	Failed, %	95% interval	Normal for this model at that age, %	Index (100 = normal)
16	924	39.5	36.4–42.7	35.8	110.4
17	803	36.5	33.2–39.9	34.9	104.6
18	650	33.1	29.6–36.8	33.4	99.2
19	574	33.4	29.7–37.4	32.5	102.9
20	488 (rough estimate)	33.4	29.4–37.7	32.3	103.5

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 3,439 (initial tests) · Method: normal rate = this model's first-time failure share at that age across its build years (cells of 400+ tests), adjusted for each test year's overall level; cells of 30+ tests, under 500 marked rough · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

What fails most on the 2004 Mazda RX-8?

The most common failure group on cars built in 2004 is suspension: 29.1 items per 100 first tests, against 23.3 across all build years of the Mazda RX-8. These counts are not age-adjusted: cars built in 2004 were tested at ages 16 to 20.

Failure items per 100 first tests, Mazda RX-8 built 2004 against the Mazda RX-8 in all build years (2019–2024, not age-adjusted)
Failure group	Built 2004, per 100	All build years, per 100	Items
Suspension	29.1	23.3	1,008
Lamps, reflectors and electrical equipment	26	23.7	900
Noise, emissions and leaks	25.3	20.9	876
Brakes	17.5	15.7	607
Body, chassis, structure	9.3	6.1	321

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 3,465 (initial tests of this build year) · Method: failure items grouped by DVSA's top-level defect groups, per 100 initial tests; groups with 30+ items · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

How does 2004 compare with the years around it?

Among the 8 published build years of the Mazda RX-8, 2004 ranks 7 (1 = fails least for its age). 2003: index 104.5. 2005: index 106.3.

Mazda RX-8 build years: index against the model at the same age (2019–2024)
Build year	Index (100 = normal)	95% interval	Verdict	Tests
2003	104.5	90.2–118.8	no different (rough estimate)	580
2004	104.8	99.0–110.7	no different (rough estimate)	3,439
2005	106.3	99.7–112.9	no different (rough estimate)	2,732
2006	102.4	97.0–107.8	no different (rough estimate)	3,934
2007	100.1	94.8–105.5	no different (rough estimate)	3,939
2008	91.7	85.0–98.3	better (rough estimate)	2,390
2009	79.5	70.8–88.2	better (rough estimate)	1,231
2010	76.2	59.3–93.1	better (rough estimate)	317

Source: DVSA MOT bulk data · Window: 2019–2024 · n = 18,562 (initial tests) · Method: observed failures against those expected for the same model at the same ages, test-year level adjusted; verdict follows the printed one-decimal bound · Updated: 30 Sep 2026 · Release: dvsa-2024-v2 · CSV

How to cite this page

MOT Risk Index (2026). Mazda RX-8 2004 MOT statistics (data release dvsa-2024-v2; full dataset motriskindex-families-2024-v5, DOI 10.5281/zenodo.22975051), updated 30 September 2026. motriskindex.co.uk/cars/mazda-rx-8/2004/

How every figure is calculated: methodology. Age, test year and build year are tied together (age = test year − build year), so the test-year level is taken as observed, not estimated.

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