2018 Kia Rio MOT pass rate: 88.7% (16,876 tests)

2018-registered Kia Rios passed 88.7% of 16,876 MOT tests in 2023–2025 — 2.3 points better than all UK cars registered in 2018 (86.4%). This is one of the strongest Rio years in the age-adjusted MOT ranking, although the individual car still matters more.

88.7%Pass rate, 2018 cars

102.3Age-adjusted index (100 = average)

16,876Tests analysed

36,870 miMedian mileage at test

88.8% / 85.7%Petrol vs diesel pass rate

Is the 2018 Rio getting worse?

Pass rate of 2018-registered cars across recent test years:

Test year	Pass rate
2023	89.5% +1.4 vs same-age
2024	88.1% +1.9 vs same-age
2025	88.3% +3.6 vs same-age

The raw rate normally falls as cars age. The “vs same-age” figure compares this cohort with all UK cars registered in the same year, so normal ageing is not mistaken for a bad model year.

What fails on a 2018 Rio

#	System	Defects recorded	Share
1	Tyres	1,120	35.7%
2	Visibility	622	19.8%
3	Brakes	527	16.8%
4	Lamps, reflectors and electrical equipment	423	13.5%
5	Suspension	213	6.8%
6	Noise, emissions and leaks	90	2.9%

All Rio years compared

Registration year	Tests	Pass rate	Vs same-age	Median mileage
2006	2,757	60.0%	-4.5 pts	87,564
2007	3,469	59.7%	-5.4 pts	88,383
2008	5,925	59.3%	-5.8 pts	87,319
2009	13,989	63.0%	-3.4 pts	79,862
2010	17,807	62.9%	-4.5 pts	81,509
2011	20,178	62.9%	-6.3 pts	78,526
2012	26,550	66.7%	-4.5 pts	81,427
2013	29,323	68.8%	-4.5 pts	73,408
2014	32,520	73.2%	-2.6 pts	65,872
2015	33,641	80.7%	+2.0 pts	56,343
2016	26,134	82.8%	+1.4 pts	48,747
2017	23,889	86.3%	+2.3 pts	44,997
2018 (this page)	16,876	88.7%	+2.3 pts	36,870
2019	14,312	89.3%	+0.9 pts	29,112
2020	9,279	91.1%	+1.1 pts	23,239
2021	4,276	92.3%	+1.9 pts	22,610
2022	3,010	93.1%	+1.8 pts	20,928

Weighing up which year to buy? See the full ranking: Kia Rio years to avoid.

Buying a 2018 Rio? Two checks first

Free MOT history checkThe exact car’s failures, advisories and mileage trail — sellers can’t edit it
Topdon OBD2 scannersTopdon diagnostic scanners with full-system readouts
XTOOL diagnostic toolsXTOOL code readers for petrol and diesel cars
Autel UK testersAutel professional-grade diagnostic testers

FAQs

Is a 2018 Kia Rio reliable?

2018-registered examples passed 88.7% of their MOT tests (16,876 tests, 2023–2025), +2.3 points versus all UK cars registered in the same year. At roughly 8 years old with a median 36,870 miles, condition now varies car by car — always check the individual MOT history.

What mileage is too high for a 2018 Rio?

The median tested example shows 36,870 miles. Anything far beyond that isn't automatically bad — a motorway-mile car with consistent service records often beats a low-mileage school-run car — but price accordingly and scrutinise the mileage trail for gaps or drops.

Should I buy the petrol or diesel 2018 Rio?

In this cohort petrols pass 88.8% of tests against 85.7% for diesels. Mileage and use can explain part of that gap, so treat it as a reason to inspect DPF and emissions history, not a fuel-type verdict.

Source: DVSA Anonymised MOT tests and results, 2023–2025 extracts (96 million Class 4 initial tests; retests excluded). Only vehicles old enough for a routine first MOT are included. Age-adjusted figures compare the model-year cohort with all vehicles of the same registration year tested in the same calendar year. Contains public sector information licensed under OGL v3.0.