Common Issues

• Electrical system problems, particularly with the window regulators and central locking.
• Cooling system weaknesses, such as radiator and water pump failures.
• Age-related rust, especially around the wheel arches and undercarriage.
• Suspension wear, often requiring bushings and shock absorber replacements.

Maintenance Tips

• Regularly check and maintain the cooling system to prevent overheating.
• Inspect and lubricate window regulators and door locks periodically.
• Protect against rust with regular underbody inspections and rust-proofing treatments.
• Follow a consistent oil change schedule with high-quality oil to ensure engine longevity.

Typical Repair/Ownership Cost Ranges

• Basic service (oil change, filter replacement): $150 - $250
• Cooling system repairs (radiator, water pump): $500 - $1,200
• Suspension overhauls: $700 - $1,500
• Electrical repairs: $200 - $800

Buying Advice

• Inspect for rust, especially in the undercarriage and wheel arches.
• Check the service history for regular maintenance and major repairs.
• Test all electrical components to ensure functionality.
• Take the car for a test drive to listen for unusual noises in the suspension or engine.

FAQs

How fuel-efficient is the 1989 BMW 635CSi? The 1989 BMW 635CSi averages around 15-20 miles per gallon, depending on driving conditions.

What kind of oil is recommended for this engine? It is recommended to use high-quality synthetic oil with a viscosity of 10W-40.

How often should the timing belt be replaced? The 635CSi uses a timing chain, which does not require regular replacement like a timing belt.

Are parts readily available for this model? Parts are generally available, though some may need to be sourced from specialty suppliers or BMW dealerships.

Is this car reliable for daily use? While reliable, due to its age, it might require more frequent maintenance and attention than newer models.

What are the common signs of cooling system failure? Look out for overheating, coolant leaks, and temperature gauge fluctuations.

Does the 1989 635CSi have modern safety features? This model lacks many modern safety features like airbags found in newer vehicles.