8-Series (E31) – MY1991-1997

BMW 850CSi (E31)
BMW 850CSi (E31) – photo by M536

BMW 8-Series (E31)

Engines

  • M60 (840Ci MY91-95)
  • M62 (840Ci MY95+)
  • M70 (850i)
  • M73 (850Ci)
  • S70 (850CSi)

Problems

All Vehicles

  • Cooling system:
    • Plastic radiators
    • Expansion bottles – can split without warning
    • Viscous fan – clutch-driven fan will wear out the viscous coupling and can cause temperatures to rise at idle; replacement of the viscous coupling is simple
    • Hose that runs from the cooling system accumulator to the heater system bursts for no reason
  • PCV valve – symptoms include smoke at start-up or under hard acceleration, and a noisy idle
  • Inlet manifold seals – symptoms include noisy idle
  • Manual transmissions – synchros are susceptible to damage if fluid other than Dexron II is used

Certain Vehicles

  • Early models: problems with hazard lights and turn signals have been attributed to the flasher relay or crash sensor control module