MG 3 common problems and MOT failures
What goes wrong on a used MG 3, year by year: known faults from UK buying guides, the parts flagged at MOT more than on other cars (from 64,185 MOTs done during 2023–2025), and what to check before you buy one.
The 2025 MG 3
Cars registered in 2025 haven’t had their first MOT yet (it’s due at 3 years old), so there are no MOT results to show. There are no known faults on record for this year in the UK buying guides we use, so the rest of this page covers the MG 3 as a whole.
What to check on a 2025 car
- Warranty left
Ask for the date it was first registered and check how much of the maker’s warranty is left, and that it transfers to you. Electric and hybrid batteries usually have a longer, separate warranty.
- Servicing
Servicing on time with the maker’s schedule keeps the warranty valid. Ask for the service book or the dealer’s digital record.
- Finance
Nearly new cars are often still on finance. A history check shows outstanding finance, and whether it has been written off or stolen.
- Recalls
Ask whether any recall work has been done, and check the reg on GOV.UK’s free recall checker.
- Logbook (V5C)
The name and address should match the seller, and the VIN on the V5C should match the car.
Other years
Most years have their own guide. The year is when the car was first registered (it’s on the logbook, or check the reg below).
What usually goes wrong with an MG 3?
Known faults reported by owners, mechanics and UK buying guides, in our own words. Most apply to certain years or engines only, so check which the car has.
- Cars registered 2013–2023 · Early cars
Timing chain stretch (early cars)
On early cars the timing chain can stretch and jump a tooth, causing rough running and poor starting, and eventually engine failure. An upgraded chain is available.
At the viewing: Listen for a rattle at start-up and check it starts and idles smoothly.
- Cars registered 2013–2023 · All engines
Clutch pedal sticking down
On some cars the clutch pedal has gone to the floor and not come back.
At the viewing: Press the clutch several times and make sure it returns fully every time.
- Cars registered 2013–2023 · Early cars
Leaky door seals (early cars)
Some early cars let water in past the door seals.
At the viewing: Feel the carpets and seats for damp.
- Cars registered 2013–2023 · All engines
Sensor faults and fuel tank strap recall
Rear parking sensors and other sensors and displays can fail. A recall covered fuel tank strap bolts that weren't made to the right spec.
At the viewing: Test the parking sensors and run the free DVSA recall check on the reg.
Common MG 3 MOT failures to check
Parts flagged at MOT well above the usual rate for cars the same age, in more than one year. From the DVSA’s results for every MOT done in Great Britain during 2023–2025.
Sub-frame
up to 38× usualStands out on cars registered in 2014, 2015, 2016, 2017 and 2018.
Rough price £300–£1,000 our estimateAt the viewing: Look underneath at the frame the suspension bolts to. Flaky rust or holes are expensive to fix.
Rigid brake pipes
up to 7.2× usualStands out on cars registered in 2014, 2015, 2016, 2017 and 2018.
Rough price £100–£400 our estimateAt the viewing: Ask to see underneath, or check the MOT advisories: corroded brake or fuel pipes get worse every year and fail the MOT when they do.
Suspension arm
up to 41× usualStands out on cars registered in 2015, 2016, 2017 and 2018.
Rough price £120–£180 (one arm) ClickMechanicAt the viewing: Listen for clunks over bumps and feel for the steering wandering. Worn arm bushes show as cracked rubber near the wheels.
Suspension arm bushes and joints
up to 3.6× usualStands out on cars registered in 2014, 2015, 2016 and 2017.
Rough price £120–£180 (one arm) ClickMechanicAt the viewing: Listen for clunks over bumps and feel for the steering wandering. Worn arm bushes show as cracked rubber near the wheels.
Headlight aim
up to 3.3× usualStands out on cars registered in 2019, 2020, 2021 and 2022.
Rough price £20–£60 our estimateAt the viewing: Park facing a wall at night or in a garage and check both headlight beams sit level. Aim is a cheap adjustment.
Airbag warning light
up to 21.7× usualStands out on cars registered in 2014 and 2015.
Rough price £10–£80 our estimateAt the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.
MG 3 MOT pass rate by year
Of the years since 2005 with plenty of MOT tests, the 2014 MG 3 did best (68% passed first time, 2 points below all 2014 cars) and the 2017 did worst (72%, 8 points below all 2017 cars). Older cars fail more, so compare each year with all cars registered the same year.
Questions to ask the seller before buying an MG 3
Ask before you travel to see it. A seller who knows the car will have answers, and receipts.
- Has the upgraded timing chain been fitted?
- Any recent work on the sub-frame? (Flagged at MOT 38× as often on the MG 3 as on other cars the same age.)
- Any recent work on the rigid brake pipes? (Flagged at MOT 7.2× as often on the MG 3 as on other cars the same age.)
- Any recent work on the suspension arm? (Flagged at MOT 41× as often on the MG 3 as on other cars the same age.)
- Can I see the service history and receipts for any big jobs?
Looking at an MG 3?
Check the actual car: its own MOT history, whether it already shows these weak spots and what to ask the seller. Free, no sign-up.
Where this comes from: MOT figures are the DVSA’s anonymised results for every MOT test done in Great Britain during 2023–2025, grouped by the year each car was first registered. How many are on the road is from the Department for Transport’s vehicle licensing statistics. Known faults are from UK buying guides, in our own words, with links. How we score