Used car guide

1992 Mercedes-Benz 300: common problems and what to check

What gets flagged at MOT on 1992 Mercedes-Benz 300s, from 362 tests in 2025, plus known faults and what to look at before you buy one.

Small sample: only 362 of these were MOT tested in 2025, so treat the percentages as rough. The known faults below don't depend on it.

362MOT tests in 2025
78%pass first time (all 1992 cars: 69%)
3,600typical miles a year
2.1×the usual rate for coil springs

What stands out

Parts flagged at MOT more often on 1992 Mercedes-Benz 300s than on all cars registered in 1992.

  • Coil springs2.1× usual
    Mercedes-Benz 300
    11% All 1992 cars
    5.2%

    Failed outright at MOT: 1.7%, against 0.6% of all 1992 cars. The rest were advisories or minor defects.

    Rough price £175–£400 (pair, one axle) ClickMechanic

    At the viewing: Look behind each wheel for a snapped spring coil, and listen for a clunk or twang when turning the wheel lock to lock with the car stopped.

By area

The share of 1992 Mercedes-Benz 300 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    30% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Brakes
    27% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Lights and electrics
    23% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Oil and fluid leaks
    18% of testsRough price £80–£600

    At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

  • Tyres
    14% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Wipers, windscreen and mirrors
    8% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

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Other years

YearMOT testsMost flagged
1993184Suspension 30%
1991337Suspension 35%
1990280Suspension 29%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 1992 Mercedes-Benz 300s registered in 1992. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score