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Bmw Bmw E31 8 Series

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BMW E31 8 Series: A Comprehensive Guide

The BMW E31 8 Series is a grand tourer built by BMW from 1989 to 1999. Replacing the E24 6 Series, it represented a significant leap in technology and design, showcasing BMW's commitment to innovation and luxury. Marketed as a high-performance coupe, it combined elegant styling, powerful engines, and advanced features, solidifying its place as a sought-after classic.

Generations

The E31 8 Series didn't undergo major generational changes during its production run, but various models and engine options were introduced. Here's a summary:

  • 1989-1994: Early Models (850i, 850Ci)
    • Introduced with the M70 5.0L V12 engine.
    • Later models (850Ci) received the updated M73 5.4L V12.
    • Available with either a 4-speed automatic or a 6-speed manual transmission.
  • 1994-1996: 840Ci
    • Introduced with the M60 4.0L V8 engine.
    • Offered a more accessible entry point to the 8 Series.
  • 1996-1999: 840Ci, 850Ci (Final Years)
    • 840Ci transitioned to the M62 4.4L V8 engine, offering improved efficiency and performance.
    • End of production for the E31 8 Series.
  • 1992-1996: 850CSi
    • High performance version featuring the S70 5.6L V12 engine.
    • Upgraded suspension, brakes, and styling.
    • Available only with a 6-speed manual transmission.

Reliability & Common Issues

The E31 8 Series is a complex car, and its age means that certain issues are common. Careful inspection and maintenance are crucial.

Engine (V12 and V8)

  • V12 (M70, M73, S70):
    • Oil Leaks: Valve cover gaskets, timing chain cover gaskets, and rear main seals are prone to leaking.
    • Cooling System: The V12 is sensitive to overheating. Regularly check and replace the radiator, water pump, thermostat, and hoses. Consider upgrading to a more robust radiator.
    • Ignition System: Two distributors and two ECUs make this system complex. Issues can include faulty distributors, worn rotors and caps, and failing ignition coils.
    • Fuel Injectors: Injectors can become clogged with age, leading to poor performance. Consider ultrasonic cleaning or replacement.
    • VANOS (S70 only): The single VANOS unit on the S70 can fail and require rebuilding.
  • V8 (M60, M62):
    • Timing Chain Guides: A well known issue on the M60 and early M62 engines. The plastic guides can become brittle and break, leading to significant engine damage. Listen for a rattling noise at idle.
    • Valve Stem Seals: Can harden with age, resulting in increased oil consumption and blue smoke on startup.
    • Intake Manifold Gaskets: Prone to leaking, leading to vacuum leaks and rough running.
    • Cooling System: Similar to the V12, regular maintenance of the cooling system is essential.

Transmission

  • Automatic Transmissions:
    • Fluid Leaks: Check for leaks around the transmission pan and seals.
    • Shifting Issues: Slipping, harsh shifting, or delayed engagement can indicate internal wear. Regular fluid changes are crucial.
    • Torque Converter: The torque converter can fail, leading to poor performance.
  • Manual Transmissions:
    • Clutch Wear: Check for clutch slippage or a high engagement point.
    • Synchro Wear: Difficulty shifting into certain gears can indicate worn synchros.

Electrical System

  • High Beam Assist Module: Commonly fails.
  • Instrument Cluster: Pixel loss in the instrument cluster is a common issue.
  • Central Locking System: Can be unreliable due to faulty actuators or wiring.
  • Window Regulators: Prone to failure, especially the driver's side.
  • Batteries: The E31 requires a high-quality battery, and maintaining proper voltage is crucial for the complex electronics.

Suspension & Brakes

  • Self-Leveling Suspension (SLS): Found on some models. The hydraulic accumulators and struts can leak and fail. Conversion to conventional suspension is a common alternative.
  • Control Arm Bushings: Wear and tear on control arm bushings can lead to poor handling and vibrations.
  • Brake Calipers: Check for seized calipers or leaks.
  • ABS System: Can experience issues due to faulty sensors or a failing control module.

Body & Interior

  • Rust: Check for rust in the usual areas, such as wheel wells, rocker panels, and around the sunroof.
  • Interior Trim: Leather upholstery can crack and wear. Wood trim can fade or crack.
  • Convertible Top (if applicable): Inspect the condition of the fabric and the operation of the mechanism.

Driving Experience

The E31 8 Series offers a unique blend of luxury, performance, and style. It's a true grand tourer, designed for comfortable long-distance cruising.

Pros:

  • Smooth Power Delivery: The V12 engines provide effortless acceleration and a refined driving experience. Even the V8s offer ample power for most situations.
  • Comfortable Ride: The suspension is tuned for comfort, making it well-suited for long journeys.
  • Distinctive Styling: The E31's sleek and elegant design still turns heads today.
  • Advanced Features: For its time, the E31 was packed with advanced technology, including traction control, anti-lock brakes, and a sophisticated onboard computer.

Cons:

  • Complexity: The E31 is a complex car, which can make maintenance and repairs more challenging and expensive.
  • Weight: The E31 is a heavy car, which can impact handling and fuel economy.
  • Maintenance Costs: Parts can be expensive and difficult to find, especially for the V12 models.
  • Fuel Economy: The V12 engines are not known for their fuel efficiency.

Buying Advice

Buying an E31 8 Series requires careful consideration and due diligence. Here's some advice:

What Years to Look For:

  • 1995-1997 840Ci (M62 Engine): Offers a good balance of performance, reliability, and affordability. The M62 engine is generally considered more reliable than the M60.
  • Late Model 850Ci (M73 Engine): The M73 V12 is an improvement over the earlier M70.
  • 850CSi: If you're looking for the ultimate E31, the 850CSi is the one to get. However, be prepared to pay a premium and factor in higher maintenance costs.

What to Avoid (or be very cautious about):

  • Early 840Ci (M60 Engine): The M60 engine is prone to timing chain guide failure, which can be a very expensive repair.
  • Cars with Poor Maintenance History: Avoid cars with gaps in the service records or signs of neglect.
  • Cars with Extensive Modifications: Unless the modifications were done professionally and are well-documented, it's best to avoid heavily modified cars.

Key Things to Check:

  • Service History: Obtain complete service records to verify maintenance and repairs.
  • Engine Condition: Check for oil leaks, unusual noises, and smooth running. Perform a compression test if possible.
  • Transmission Condition: Test the transmission for smooth shifting and proper engagement.
  • Electrical System: Check all electrical functions, including lights, windows, central locking, and instrument cluster.
  • Suspension and Brakes: Inspect the suspension for worn bushings and leaking struts. Check the brakes for proper operation and signs of wear.
  • Rust: Thoroughly inspect the body for rust, especially in the wheel wells, rocker panels, and around the sunroof.
  • Pre-Purchase Inspection: Have a qualified BMW mechanic perform a pre-purchase inspection to identify any potential issues.

The BMW E31 8 Series is a rewarding car to own, but it requires dedication and resources to maintain properly. With careful research and a thorough inspection, you can find a well-maintained example that will provide years of enjoyment.

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