2004 Mercury Grand Marquis

The 2004 Mercury Grand Marquis is a full-size sedan known for its comfortable ride, spacious interior, and traditional body-on-frame construction. It came standard with a 4.6L Modular V8 engine, producing around 220 horsepower and 275 lb-ft of torque. No other engine options were available. A 4-speed automatic transmission was the only transmission option. Owners often praise the Grand Marquis for its reliability, ease of maintenance, and smooth highway cruising. Common complaints include its relatively poor fuel economy and somewhat dated styling.

Engine

4.6L Modular V8

• Intake Manifold Cracks
  • Description/Symptoms: Cracking in the coolant crossover portion of the intake manifold can lead to coolant leaks. The engine may overheat, and coolant loss will be apparent.
  • Solution: Replacement of the intake manifold, often with an updated design to prevent future cracking.
  • Estimated Cost to Fix: $300 - $600
• Spark Plug Thread Failure
  • Description/Symptoms: The factory spark plugs are known for ejecting out of the cylinder head due to minimal thread contact.
  • Solution: Removal of the spark plug and installation of thread inserts.
  • Estimated Cost to Fix: $300 - $800+ depending on the number of cylinders affected

Transmission

4-Speed Automatic (4R70W/4R75W)

• Harsh Shifting/Slipping
  • Description/Symptoms: Delayed engagement, harsh shifts between gears, or slipping during acceleration. This can be caused by worn valve body components or solenoids.
  • Solution: Transmission fluid flush, valve body rebuild or replacement, or complete transmission rebuild/replacement.
  • Estimated Cost to Fix: $100 (fluid flush) - $2,500+ (rebuild/replacement)
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibrations, especially at lower speeds or during acceleration. Can also cause stalling or difficulty shifting.
  • Solution: Torque converter replacement.
  • Estimated Cost to Fix: $500 - $1200

Suspension

• Air Suspension Compressor Failure (if equipped)
  • Description/Symptoms: Rear of the vehicle sagging, compressor running constantly or not at all, “Check Air Suspension” warning light.
  • Solution: Replacement of the air suspension compressor, often along with the air springs/bags if they are leaking. Converting to coil springs is another option.
  • Estimated Cost to Fix: $300 - $800+ (compressor), $200 - $600+ (air springs), $300 - $600+ (coil spring conversion)
• Ball Joint Wear
  • Description/Symptoms: Clicking or clunking noises from the front suspension, especially when turning or going over bumps. Loose or sloppy steering.
  • Solution: Replacement of the worn ball joints.
  • Estimated Cost to Fix: $200 - $500 per ball joint (lower or upper)

Electrical

• Blend Door Actuator Failure
  • Description/Symptoms: Inconsistent or no temperature control, clicking noises behind the dashboard. One side blows hot air while the other blows cold.
  • Solution: Replacement of the faulty blend door actuator.
  • Estimated Cost to Fix: $150 - $400
• Lighting Issues
  • Description/Symptoms: Headlights or taillights not working, often due to corrosion in the sockets or wiring.
  • Solution: Cleaning or replacing corroded sockets and wiring, bulb replacement.
  • Estimated Cost to Fix: $50 - $200+
• Door Lock Actuator Failure
  • Description/Symptoms: One or more door locks failing to lock or unlock with the remote or door switch.
  • Solution: Replacement of the faulty door lock actuator.
  • Estimated Cost to Fix: $150 - $350

Exterior

• Rust near Rear Wheel Wells and Rocker Panels
  • Description/Symptoms: Bubbling paint or visible rust forming near the rear wheel wells and along the rocker panels, especially in areas with harsh winters.
  • Solution: Rust repair, body panel replacement.
  • Estimated Cost to Fix: $300 - $1000+ depending on severity

Interior

• Broken Power Window Regulators
  • Description/Symptoms: Window regulator failing to move the window up or down properly. Grinding noises or the window falling into the door.
  • Solution: Window regulator replacement.
  • Estimated Cost to Fix: $150 - $400 per window

Recalls

• None Found

Summary

The 2004 Mercury Grand Marquis is generally a reliable vehicle, but owners should be aware of potential issues like intake manifold cracks, spark plug thread issues, transmission problems, air suspension failures (if equipped), and electrical gremlins. While some repairs, like replacing a blend door actuator or repairing minor rust, are relatively inexpensive, others, such as a transmission rebuild or air suspension overhaul, can be costly. Overall, pre-purchase inspection focusing on these common issues will assist in mitigating potential costly repair bills.