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BMW 420 Common Problems & Reliability

Based on 4,146 MOT tests from 482 vehicles analysed by VehicleScore. The figures below describe that VehicleScore sample. Recurring issues seen in VehicleScore MOT data are not a claim that every BMW 420 has the same fault.

BMW 420's have a extremely good reliability rating of 760/999. The score was calculated from the average of every BMW 420 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.

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Check a BMW 420 before you buy

Enter your registration to see available vehicle history information including service records, MOT, mileage, write-off status, outstanding finance and more.

BMW 420 side view
  • Service history

    Dealer & service records

  • MOT records

    Past & current MOT data

  • Write-off check

    Check for insurance write-offs

  • Finance check

    Outstanding finance & theft checks

Fuel TypeYearReliability ScoreAvg MileageSample Size
N/AN/A842/999Excellent84,920 miles1,886 vehicles
N/AN/A802/999Excellent73,154 miles3,470 vehicles
N/AN/A781/999Very good89,059 miles1,623 vehicles
N/AN/A760/999Very good81,862 miles1,931 vehicles
N/AN/A756/999Very good75,150 miles5,214 vehicles
N/AN/A735/999Very good76,049 miles7,159 vehicles
N/AN/A735/999Very good75,393 miles1,615 vehicles
N/AN/A667/999Good82,865 miles1,973 vehicles

How reliable is the BMW 420?

Based on 4,146 MOT tests from 482 vehicles analysed by VehicleScore.

Vehicles

482

MOT tests

4,146

Pass rate

85.4%

Median mileage

84,200 mi

Recurring issues seen in VehicleScore MOT data are inspection findings from this sample. They are not a statement that every BMW 420 has the same fault. The median VehicleScore in this sample is 736 out of 999.

Common BMW 420 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.

Tyre wear

VehicleScore MOT data includes 751 advisory comments and 186 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 REAR TYRE WORN CLOSE TO LEGAL LIMIT/WORN ON EDGE (5.2.3 (E))

Brake pad wear

VehicleScore MOT data includes 258 advisory comments and 35 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: REAR BRAKE PAD(S) WEARING THIN (1.1.13 (A) (II))

Brake disc wear

VehicleScore MOT data includes 205 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))

Steering rack issues

VehicleScore MOT data includes 65 advisory comments in this group. Seen mainly as an advisory. These are comment occurrences, not a share of all cars.

These MOT comments record play, a leak, or a damaged gaiter on the steering rack.

What to inspect

Check for play at the steering wheel and look for split rack gaiters.

Example MOT wording: OFFSIDE FRONT PLAY IN STEERING RACK INNER JOINT(S)

Shock absorber issues

VehicleScore MOT data includes 37 advisory comments and 27 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 shock absorbers or dampers that were leaking, misting, or insecure. A light misting of oil on a damper is not an engine oil leak.

What to inspect

Look for oil misting on the damper body and listen for knocks over bumps.

Example MOT wording: NEARSIDE REAR SHOCK ABSORBERS HAS LIGHT MISTING OF OIL (5.3.2 (B))

Windscreen damage

VehicleScore MOT data includes 13 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: WINDSCREEN WASHER PROVIDES INSUFFICIENT WASHER LIQUID (3.5 (A))

Registration plate condition

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 a number plate that was deteriorated, insecure, or did not meet the plate rules.

What to inspect

Check both plates are secure, clean, and clearly readable.

Example MOT wording: FRONT REGISTRATION PLATE DOES NOT CONFORM TO THE SPECIFIED REQUIREMENTS (0.1 (D))

BMW 420 MOT reliability by year

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

YearVehiclesMOT testsPass rateRecurring issues seen
2020189280.4%Tyre wear, Brake pad wear
20195230087.3%Tyre wear, Brake disc wear
20188558986.4%Tyre wear, Brake pad wear
20175847987.9%Tyre wear, Brake pad wear
20169379286.2%Tyre wear, Brake pad wear
20158687786.3%Tyre wear, Brake disc wear
20147991781.9%Tyre wear, Brake pad wear
201388188.9%Tyre wear, Parking brake faults

What to check when buying a used BMW 420

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.

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

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

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

  • Steering rack issues. Check for play at the steering wheel and look for split rack gaiters.

  • Shock absorber issues. Look for oil misting on the damper body and listen for knocks over bumps.

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

  • Registration plate condition. Check both plates are secure, clean, and clearly readable.

Buying a BMW 420?

Common problems tell you what can affect BMW 420s 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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