Used car guide

2004 BMW 645i: common problems and MOT failures

What MOT testers find on the BMW 645i first registered in 2004: we looked at the 3,251 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

3,251MOTs of 2004 cars, done in 2023–2025
71%pass first time (all 2004 cars: 57%)
5,400typical miles a year
2×the usual rate for engine oil leaks

What goes wrong more than usual on a 2004 BMW 645i?

Parts flagged at MOT more often on the 2004 BMW 645i than on all cars registered in 2004.

  • Engine oil leaks2× usual
    BMW 645i
    29.5% All 2004 cars
    14.6%

    Failed outright at MOT: 0.7%, against 0.4% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £80–£600 our estimate

    At the viewing: Look under the engine and where the car is usually parked for fresh oil. Ask whether the leak has been looked at.

  • Suspension arm bushes and joints1.7× usual
    BMW 645i
    16% All 2004 cars
    9.4%

    Failed outright at MOT: 3%, against 2.1% of all 2004 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.

Better than most

Headlights: 3.5% here, against 13.2% of all 2004 cars. Exhaust system: 3.1% here, against 9.7% of all 2004 cars.

Common 2004 BMW 645i MOT failures and advisories

The share of 2004 BMW 645i MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    35% 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
    34% 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.

  • Oil and fluid leaks
    31% 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
    27% 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.

  • Lights and electrics
    18% of testsRough price £10–£80

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

  • 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.

Questions to ask the seller before buying a 2004 BMW 645i

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

  1. Any recent work on the engine oil leaks? (Flagged at MOT 2× as often on the 2004 BMW 645i as on other cars the same age.)
  2. Any recent work on the suspension arm bushes and joints? (Flagged at MOT 1.7× as often on the 2004 BMW 645i as on other cars the same age.)
  3. Can I see the service history and receipts for any big jobs?

Looking at a BMW 645i?

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 BMW 645i compared

YearMOT testsMost flagged
20051,459Suspension 34%

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of BMW 645i cars first registered in 2004. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score