2004 Mitsubishi Diamante

The 2004 Mitsubishi Diamante is a mid-size sedan known for its comfortable ride and spacious interior. It was only available with one engine option: a 3.5-liter V6 producing approximately 205 horsepower and 231 lb-ft of torque. This engine was paired with a 4-speed automatic transmission. Owners often praised the car for its smooth ride and reliability (when properly maintained) at the time, but some found the fuel economy lacking and the styling somewhat bland. Others have complained about the availability of parts as the vehicle ages.

Engine

3.5L V6

• Oil Leaks
  • Description/Symptoms: Oil leaks are common around the valve cover gaskets and oil pan gasket. Symptoms include visible oil spots under the car, a burning oil smell, and low oil levels.
  • Solution: Replace the valve cover gaskets and/or oil pan gasket.
  • Estimated Cost to Fix: $150 - $400+ depending on the location of the leak and labor rates.
  • Recalls: None Found
• Idle Air Control (IAC) Valve Failure
  • Description/Symptoms: Rough idling, stalling, or difficulty starting can be caused by a faulty IAC valve.
  • Solution: Replace the IAC valve.
  • Estimated Cost to Fix: $100 - $250+
  • Recalls: None Found

Transmission

4-Speed Automatic

• Shift Problems/Slipping
  • Description/Symptoms: Hard or delayed shifts, slipping between gears, or failure to shift can occur due to worn clutch packs or valve body issues within the 4-speed automatic transmission.
  • Solution: A transmission fluid flush may temporarily alleviate the issue, but a rebuild or replacement of the transmission is often necessary.
  • Estimated Cost to Fix: $200 (fluid flush) - $1,500-$3,000+ (rebuild or replacement)
  • Recalls: None Found

Suspension

• Strut Mount Failure
  • Description/Symptoms: Clunking or rattling noises from the front or rear suspension, especially when going over bumps. Can also affect steering response and handling.
  • Solution: Replace the strut mounts.
  • Estimated Cost to Fix: $200 - $500+ per axle.
  • Recalls: None Found
• Worn Control Arm Bushings
  • Description/Symptoms: Worn control arm bushings can cause clunking noises, poor handling, and uneven tire wear.
  • Solution: Replace the worn control arm bushings, or the entire control arm assembly if bushings are not available separately.
  • Estimated Cost to Fix: $150-$400+ per control arm, depending on labor rates and if the entire assembly is replaced.
  • Recalls: None Found

Electrical

• Power Window Motor Failure
  • Description/Symptoms: Windows that operate slowly or fail to operate at all.
  • Solution: Replace the faulty power window motor.
  • Estimated Cost to Fix: $150 - $350+ per window.
  • Recalls: None Found
• Alternator Failure
  • Description/Symptoms: Dimming headlights, a battery that won’t hold a charge, and/or a battery warning light.
  • Solution: Replace the alternator.
  • Estimated Cost to Fix: $300 - $500+
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust can develop on the undercarriage, wheel wells, and body panels, particularly in areas exposed to road salt.
  • Solution: Rust repair is the solution; however, this is temporary and rust will appear again.
  • Estimated Cost to Fix: $100 - $1,000+ depending on the severity and location.
  • Recalls: None Found

Interior

• Dashboard Cracking
  • Description/Symptoms: Cracks can appear on the dashboard surface, particularly in areas exposed to sunlight.
  • Solution: Replacement of the dashboard, or installation of a dashboard cover.
  • Estimated Cost to Fix: $200 - $1,000+ (depending on method of fixing the issue)
  • Recalls: None Found

Summary

The 2004 Mitsubishi Diamante can be a reliable vehicle if properly maintained, but potential buyers should be aware of some common issues. Engine oil leaks, transmission problems, suspension wear, electrical failures, and rust are the most common issues. Costs can range from relatively inexpensive fixes like replacing an IAC valve to more costly repairs like transmission rebuilds or rust repair. It’s advisable to have a mechanic inspect any used Diamante before purchase to assess the condition of these common problem areas.