1986 BMW 6 Series 3.5L Petrol · C69 WHA

Fuel economy for a 3.5-litre petrol BMW 6 Series of this era is likely to be in the region of 18-25 mpg depending on use, making it unsuitable as an economical daily driver. Road tax for a vehicle registered before 1986 should fall within the historic vehicle class, potentially exempting it from standard VED, but this should be confirmed with the DVLA. Insurance will be specialist classic car cover, typically reasonable through agreed-value policies, but shop around as quotes vary significantly.

Maintenance costs are the biggest consideration, as parts for E24 6 Series cars range from readily available (suspension, filters, brake components) to increasingly scarce (interior trim, specific body panels, dashboard components). Specialist hourly rates typically run higher than general garages, and a major service on the M30 engine can easily run into four figures. Budget conservatively and set aside a contingency fund for unexpected discoveries once you start using the car regularly.

Start with a thorough inspection of the body and chassis for corrosion, particularly around the wheel arches, sills, jacking points, and rear subframe mounting areas, as these are well-documented weak points on E24-generation BMWs. The 2022 coil spring failure should prompt a close look at the suspension components, springs, shock absorbers, and subframe mounting points for signs of rust or fatigue. Examine the underbody on a ramp if possible, as surface rust on a 40-year-old car is normal but structural corrosion is not.

The 3.5-litre M30 engine should be inspected for oil leaks from the valve cover gasket, oil filter housing, and rear main seal, all of which are common on these units. Check the cooling system for signs of recent work, as the plastic components on these cars degrade with age, and overheating can cause expensive damage. Listen for timing chain rattle on startup and check the condition of the drive belts and hoses, which are likely due for renewal if not recently replaced.

Inspect the interior for crumbling dashboard foam, failing seat upholstery, and functional issues with the electric windows and sunroof, as these are known weak points on E24 cars. Verify all electrical systems work, including the central locking, instruments, and heating controls, as electrical gremlins can be time-consuming to trace and repair. Finally, check the provenance carefully, confirming the registration document matches the car and that there is no outstanding finance or insurance loss record.