1991 Mercedes-Benz 350SDL

Introduction: The 1991 Mercedes-Benz 350SDL is a luxurious and powerful sedan powered by a 3.5L inline-6 diesel engine. It is known for its comfortable ride, spacious interior, and durable construction. Other engine options for the vehicle were a 3.0L I6 diesel (2.5L Turbo Diesel not available in the US) and a 5.6L V8 gasoline engine.

Engine

• 3.5L Inline-6 Diesel Cylinder Head Gasket Failure:
  • Description/Symptoms: Coolant leaking, overheating, white smoke from exhaust
  • Solution: Replace cylinder head gasket
  • Estimated Cost to Fix: $1,000 - $2,000 Timing Chain Guide Wear:
  • Description/Symptoms: Rattling or grinding noise from engine, loss of power
  • Solution: Replace timing chain and guides
  • Estimated Cost to Fix: $1,500 - $2,500 Injector Pump Failure:
  • Description/Symptoms: Difficulty starting, black smoke from exhaust, poor fuel economy
  • Solution: Replace injector pump
  • Estimated Cost to Fix: $2,000 - $3,000 Recalls:
  • NHTSA Campaign ID: 91V177000: Glow plug relay may overheat and cause fire
  • NHTSA Campaign ID: 91V074000: Fuel pump may fail, causing engine stall

Transmission

• 4-Speed Automatic Transmission (4G-Tronic) Transmission Slipping:
  • Description/Symptoms: Difficulty shifting gears, loss of power
  • Solution: Overhaul or replace transmission
  • Estimated Cost to Fix: $2,500 - $4,000 Torque Converter Failure:
  • Description/Symptoms: Shuddering or slipping during gear shifts, overheating
  • Solution: Replace torque converter
  • Estimated Cost to Fix: $1,500 - $2,500

Suspension

• No Issues Found

Electrical

• Alternator Failure:
  • Description/Symptoms: Dimming lights, dashboard warning lights, difficulty starting
  • Solution: Replace alternator
  • Estimated Cost to Fix: $500 - $1,000 Battery Drain:
  • Description/Symptoms: Battery dies quickly, difficulty starting
  • Solution: Check for parasitic draw, replace battery
  • Estimated Cost to Fix: $200 - $500

Exterior

• Headlight Switch Failure:
  • Description/Symptoms: Headlights do not turn on or turn off
  • Solution: Replace headlight switch
  • Estimated Cost to Fix: $200 - $400

Interior

• Radio Display Failure:
  • Description/Symptoms: Radio display goes blank or flickers
  • Solution: Replace radio display
  • Estimated Cost to Fix: $500 - $1,000 Window Regulator Failure:
  • Description/Symptoms: Windows do not roll up or down smoothly
  • Solution: Replace window regulator
  • Estimated Cost to Fix: $300 - $500

Summary: The 1991 Mercedes-Benz 350SDL is generally a reliable and well-built vehicle. However, there are some common issues to be aware of, particularly with the engine and transmission. The severity of the issues varies, but some can be expensive to repair. Potential owners should consider these potential issues when purchasing a used 350SDL and factor in the cost of repairs when budgeting.