2004 Subaru Impreza

The 2004 Subaru Impreza is a compact car known for its standard all-wheel drive and sporty handling, particularly in the WRX and STi trims. Engine options for the 2004 Impreza include a 2.5L naturally aspirated flat-4 engine producing 165 horsepower and 166 lb-ft of torque in the RS trim, and a 2.0L turbocharged flat-4 engine that produced 227 horsepower and 217 lb-ft of torque in the WRX trim. Transmission options are a 5-speed manual transmission and a 4-speed automatic transmission. Owners appreciate the Impreza’s reliability, all-weather capability, and fun-to-drive nature. Common complaints include road noise, fuel economy (especially with the WRX), and some specific mechanical issues that arise with age.

Engine

2.5L Naturally Aspirated Flat-4 (RS)

• Head Gasket Failure
  • Description/Symptoms: Overheating, coolant loss, white smoke from the exhaust, bubbling in the coolant overflow tank. The engine’s design with horizontally opposed cylinders makes it susceptible to head gasket leaks, especially with age.
  • Solution: Replacing the head gaskets with updated multi-layer steel (MLS) gaskets is a common fix. Machining the cylinder heads may also be necessary if they are warped.
  • Estimated Cost to Fix: $1,500 - $2,500+
  • Recalls: None Found
• Oil Leaks
  • Description/Symptoms: Oil spots under the car, burning oil smell, low oil level. Common leak points include the valve cover gaskets, oil pan gasket, and front crankshaft seal.
  • Solution: Replacing the leaking gaskets and seals.
  • Estimated Cost to Fix: $100 - $500+ depending on the location of the leak.
  • Recalls: None Found

2.0L Turbocharged Flat-4 (WRX)

• Turbocharger Failure
  • Description/Symptoms: Loss of power, whistling or whining noise from the turbocharger, excessive smoke from the exhaust.
  • Solution: Replacing the turbocharger. Upgrading to a more robust aftermarket turbocharger is also an option.
  • Estimated Cost to Fix: $1,000 - $2,000+
  • Recalls: None Found
• Boost Leaks
  • Description/Symptoms: Loss of power, poor fuel economy, hissing sound under acceleration. Boost leaks can occur in the intercooler piping, vacuum lines, or turbocharger itself.
  • Solution: Inspecting and replacing damaged hoses and clamps. Pressure testing the system to identify the leak.
  • Estimated Cost to Fix: $50 - $300+ depending on the location and severity of the leak.
  • Recalls: None Found
• Oil starvation to the turbo
  • Description/Symptoms: The turbocharger fails due to lack of lubrication. This can be caused by many things, including low oil level, a clogged oil screen for the turbo, or worn internal engine components.
  • Solution: Replace the turbo and inspect for other issues that may have caused the failure.
  • Estimated Cost to Fix: $1,000 - $2,500
  • Recalls: None Found

Transmission

5-Speed Manual Transmission

• Synchro Wear/Grinding Gears
  • Description/Symptoms: Difficulty shifting into certain gears, especially 2nd and 3rd, grinding noise when shifting.
  • Solution: Replacing the worn synchros or rebuilding the transmission.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• Clutch Failure
  • Description/Symptoms: Slipping clutch, difficulty shifting, high clutch pedal engagement point.
  • Solution: Replacing the clutch disc, pressure plate, and throw-out bearing.
  • Estimated Cost to Fix: $500 - $1,200+
  • Recalls: None Found

4-Speed Automatic Transmission

• Shifting Problems
  • Description/Symptoms: Harsh or delayed shifting, slipping between gears, failure to shift.
  • Solution: Replacing the transmission.
  • Estimated Cost to Fix: $1,800 - $3,500+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering, hesitation, or complete loss of power when accelerating.
  • Solution: Replacing the torque converter.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found

Suspension

• Strut and Shock Absorber Wear
  • Description/Symptoms: Bouncy ride, poor handling, excessive body roll.
  • Solution: Replacing the worn struts and shock absorbers.
  • Estimated Cost to Fix: $400 - $1,000+
  • Recalls: None Found
• Rear Lateral Link Bushing Failure
  • Description/Symptoms: Clunking noise from the rear suspension, vague handling, uneven tire wear.
  • Solution: Replacing the rear lateral link bushings or the entire lateral link assembly.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

Electrical

• Oxygen Sensor Failure
  • Description/Symptoms: Check engine light, poor fuel economy, rough running engine.
  • Solution: Replacing the faulty oxygen sensor.
  • Estimated Cost to Fix: $150 - $400+
  • Recalls: None Found
• Mass Airflow Sensor (MAF) Failure
  • Description/Symptoms: Check engine light, poor fuel economy, stalling.
  • Solution: Replacing the faulty MAF sensor.
  • Estimated Cost to Fix: $100 - $300+
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust forming on the quarter panels, rocker panels, wheel wells, and around the windshield. This is more prevalent in areas with heavy road salt use.
  • Solution: Rust repair can range from sanding and painting small spots to replacing entire body panels.
  • Estimated Cost to Fix: $100 - $3,000+ depending on severity.
  • Recalls: None Found

Interior

• No Issues Found

Summary

The 2004 Subaru Impreza is a generally reliable car, but like any vehicle of its age, it is prone to certain issues. The most common problems revolve around engine head gaskets, oil leaks, and transmission wear, especially in the higher-performance WRX trim which also sees turbocharger issues. Suspension components also wear out over time. Rust can be a significant problem depending on the geographic location of the vehicle. Repair costs can range from a few hundred dollars for minor issues to several thousand for major engine or transmission work. Potential buyers should have a pre-purchase inspection performed to assess the condition of the engine, transmission, and suspension, and to check for rust.