MG 3 Common Problems & Reliability

Based on 371 MOT tests from 61 vehicles analysed by VehicleScore. The figures below describe that VehicleScore sample. Recurring issues seen in VehicleScore MOT data are not a claim that every MG 3 has the same fault.

MG 3's have a very good reliability rating of 708/999. The score was calculated from the average of every MG 3 that has had a registered MOT.

We calculated all of the below figures by getting the score from each vehicle make/model/year/fuel, which are each calculated a score. We then generate the average score, taking into account factors such as mileage and emissions.

Also check BHP & performance, road tax, fuel economy, and CO2 emissions for the MG 3.

MG 3 (example)

Check an MG 3 before you buy

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Fuel Type	Year	Reliability Score	Avg Mileage	Sample Size
N/A	N/A	826/999Excellent	68,997 miles	1,673 vehicles
N/A	N/A	681/999Good	66,157 miles	2,080 vehicles
N/A	N/A	618/999Good	72,084 miles	1,064 vehicles

How reliable is the MG 3?

Based on 371 MOT tests from 61 vehicles analysed by VehicleScore.

Vehicles

MOT tests

371

Pass rate

77.4%

Median mileage

41,738 mi

Recurring issues seen in VehicleScore MOT data are inspection findings from this sample. They are not a statement that every MG 3 has the same fault. The median VehicleScore in this sample is 853 out of 999.

Common MG 3 MOT problems

These groups combine equivalent MOT comments, such as the same tyre note on different corners. Counts are comment occurrences in the sample, not a percentage of cars.

Corrosion

VehicleScore MOT data includes 44 advisory comments in this group. Seen mainly as an advisory. These are comment occurrences, not a share of all cars.

These MOT comments record corrosion the tester could see on the body or structure. Corrosion already named on a spring, brake, or other component is counted with that component.

What to inspect

Inspect the underside, sills, and subframe for heavy corrosion, especially where an advisory mentions it.

Example MOT wording: FRONT SUB-FRAME CORRODED BUT NOT SERIOUSLY WEAKENED (5.3.3 (B) (I))

Tyre wear

VehicleScore MOT data includes 29 advisory comments and 12 failure comments in this group. Seen as both an advisory and a failure reason. These are comment occurrences, not a share of all cars.

These MOT comments record tyres that were worn, damaged, or close to the legal tread depth when the car was inspected.

What to inspect

Check the tread depth and look for uneven wear, cracking, or damage on all four tyres.

Example MOT wording: NEARSIDE FRONT TYRE WORN CLOSE TO LEGAL LIMIT/WORN ON EDGE (5.2.3 (E))

Brake disc wear

VehicleScore MOT data includes 32 advisory comments in this group. Seen mainly as an advisory. These are comment occurrences, not a share of all cars.

These MOT comments record brake discs that were worn, scored, pitted, or corroded.

What to inspect

Look at the disc faces for deep scoring, a lip at the edge, and corrosion.

Example MOT wording: FRONT BRAKE DISC WORN, PITTED OR SCORED, BUT NOT SERIOUSLY WEAKENED (1.1.14 (A) (II))

Brake pad wear

VehicleScore MOT data includes 23 advisory comments and 3 failure comments in this group. Seen as both an advisory and a failure reason. These are comment occurrences, not a share of all cars.

These MOT comments record brake pads that were worn or below the inspection limit.

What to inspect

Ask for recent pad replacement and look at the remaining pad thickness.

Example MOT wording: FRONT BRAKE PAD(S) WEARING THIN (1.1.13 (A) (II))

Oil leak

VehicleScore MOT data includes 24 advisory comments in this group. Seen mainly as an advisory. These are comment occurrences, not a share of all cars.

These MOT comments record an oil leak noted by the tester. Shock absorber misting is counted as a damper issue, not as an engine oil leak.

What to inspect

Look under the engine for fresh oil, and check the oil level.

Example MOT wording: OIL LEAK, BUT NOT EXCESSIVE (8.4.1 (A) (I))

Suspension arm issues

VehicleScore MOT data includes 17 advisory comments and 5 failure comments in this group. Seen as both an advisory and a failure reason. These are comment occurrences, not a share of all cars.

These MOT comments record a worn, corroded, or damaged suspension arm or its pin.

What to inspect

Look for play or corrosion at the arm and ask whether it has been replaced.

Example MOT wording: OFFSIDE FRONT SUSPENSION ARM PIN OR BUSH WORN BUT NOT RESULTING IN EXCESSIVE MOVEMENT (5.3.4 (A) (I))

Windscreen damage

VehicleScore MOT data includes 11 failure comments in this group. Seen mainly as a failure reason. These are comment occurrences, not a share of all cars.

These MOT comments record chips, cracks, or other windscreen damage in the driver’s view.

What to inspect

Look for chips and cracks, especially in the area swept by the wipers.

Example MOT wording: FRONT WINDSCREEN WASHER PROVIDES INSUFFICIENT WASHER LIQUID (3.5 (A))

Parking brake faults

VehicleScore MOT data includes 8 failure comments in this group. Seen mainly as a failure reason. These are comment occurrences, not a share of all cars.

These MOT comments record a parking brake that did not hold well enough or had a component defect.

What to inspect

Test that the parking brake holds the car on a slope and releases cleanly.

Example MOT wording: PARKING BRAKE EFFICIENCY BELOW REQUIREMENTS (1.4.2 (A) (I))

MG 3 MOT reliability by year

A model year is only commented on when VehicleScore has at least 5 vehicles from that year.

Year	Vehicles	MOT tests	Pass rate	Recurring issues seen
2025	6	1	100%	No recurring grouped MOT issue in this year sample
2024	5	0	—	No recurring grouped MOT issue in this year sample
2019	8	48	81.3%	Tyre wear, Brake disc wear
2018	8	62	79%	Corrosion, Tyre wear
2017	7	60	80%	Brake disc wear, Tyre wear
2015	7	75	84%	Corrosion, Tyre wear

What to check when buying a used MG 3

This is an inspection checklist based on MOT comments in the VehicleScore sample. It does not mean the car you are looking at has these defects.

Corrosion. Inspect the underside, sills, and subframe for heavy corrosion, especially where an advisory mentions it.
Tyre wear. Check the tread depth and look for uneven wear, cracking, or damage on all four tyres.
Brake disc wear. Look at the disc faces for deep scoring, a lip at the edge, and corrosion.
Brake pad wear. Ask for recent pad replacement and look at the remaining pad thickness.
Oil leak. Look under the engine for fresh oil, and check the oil level.
Suspension arm issues. Look for play or corrosion at the arm and ask whether it has been replaced.
Windscreen damage. Look for chips and cracks, especially in the area swept by the wipers.
Parking brake faults. Test that the parking brake holds the car on a slope and releases cleanly.

Buying a MG 3?

Common problems tell you what can affect MG 3s generally. VehicleScore can check the history of the actual car you're considering.

Where does this data come from?

VehicleScore analyses MOT histories from vehicles in its own dataset. Sample sizes vary by model, and a small sample is labelled as such. MOT data records roadworthiness and inspection defects. It does not capture every mechanical or electronic problem a car can have, and a comment on one test is not proof that the model has an inherent fault.

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