Used car guide

1998 Audi A4 diesel: common problems and MOT failures

What MOT testers find on the diesel Audi A4 first registered in 1998 (diesel cars only): we looked at the 537 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

537MOTs of 1998 diesel cars, done in 2023–2025
65%pass first time (all 1998 cars: 65%)
7,200typical miles a year
2.5×the usual rate for brake discs

What goes wrong more than usual on a 1998 Audi A4 diesel?

Parts flagged at MOT more often on the 1998 Audi A4 diesel than on all cars registered in 1998.

  • Brake discs2.5× usual
    Audi A4
    23.8% All 1998 cars
    9.7%

    Failed outright at MOT: 1.7%, against 0.6% of all 1998 cars. The rest were advisories or minor defects.

    Rough price £150–£350 our estimate

    At the viewing: Look through the wheel at the brake disc: a deep lip at the edge or heavy scoring means they're worn. Feel for judder when braking.

  • Wheel bearings2.7× usual
    Audi A4
    16.9% All 1998 cars
    6.2%

    Failed outright at MOT: 1.9%, against 1% of all 1998 cars. The rest were advisories or minor defects.

    Rough price £120–£300 (one bearing) ClickMechanic

    At the viewing: Listen for a hum or growl that changes as you steer at speed.

  • Suspension arm bushes and joints2.8× usual
    Audi A4
    14.7% All 1998 cars
    5.2%

    Failed outright at MOT: 3%, against 0.9% of all 1998 cars. The rest were advisories or minor defects.

    Rough price £120–£180 (one arm) ClickMechanic

    At the viewing: Listen for clunks over bumps and feel for the steering wandering. Worn arm bushes show as cracked rubber near the wheels.

  • Ball joint2.9× usual
    Audi A4
    14.3% All 1998 cars
    4.9%

    Failed outright at MOT: 7.8%, against 1.7% of all 1998 cars. The rest were advisories or minor defects.

    Rough price £60–£150 (one joint) ClickMechanic

    At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

  • Drive shaft (CV) joints2.6× usual
    Audi A4
    13.4% All 1998 cars
    5.1%

    Failed outright at MOT: 6.3%, against 2.2% of all 1998 cars. The rest were advisories or minor defects.

    Rough price £60–£350 our estimate

    At the viewing: Drive slowly on full steering lock in both directions and listen for clicking. Look for split rubber boots behind the front wheels.

Common 1998 Audi A4 diesel MOT failures and advisories

The share of 1998 Audi A4 diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    49% 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
    39% 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
    39% 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
    26% 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
    23% 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.

  • Driveshafts and joints
    14% of testsRough price £60–£350

    At the viewing: On full steering lock, drive slowly and listen for clicking from the front wheels.

Questions to ask the seller before buying a 1998 Audi A4 diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Any recent work on the brake discs? (Flagged at MOT 2.5× as often on the 1998 Audi A4 diesel as on other cars the same age.)
  2. Any recent work on the wheel bearings? (Flagged at MOT 2.7× as often on the 1998 Audi A4 diesel as on other cars the same age.)
  3. Any recent work on the suspension arm bushes and joints? (Flagged at MOT 2.8× as often on the 1998 Audi A4 diesel as on other cars the same age.)
  4. Can I see the service history and receipts for any big jobs?

Looking at an Audi A4?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Audi A4 compared

YearMOT testsMost flagged
2026–Too new for MOT data
2025–Too new for MOT data
2024–Too new for MOT data
2023362Tyres 19%
20227,043Tyres 28%
202114,494Tyres 28%
202025,381Tyres 28%
201939,575Tyres 30%
201840,399Tyres 28%
201763,211Tyres 28%
201665,764Tyres 29%
201548,854Tyres 31%
201450,261Tyres 31%
201347,748Tyres 32%
201240,105Tyres 33%
201141,085Suspension 39%
201038,856Suspension 40%
200938,253Suspension 41%
200845,736Suspension 47%
200745,101Suspension 48%
200638,799Suspension 50%
200522,925Suspension 49%
200419,785Suspension 50%
200311,574Suspension 52%
20026,124Suspension 54%
20012,778Suspension 48%
20002,815Suspension 45%
19992,189Suspension 46%
1997812Suspension 49%
1996551Suspension 46%
1995174Brakes 40%

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Audi A4 cars first registered in 1998. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score