2004 BMW Z4

2004 BMW Z4

Overview

The 2004 BMW Z4, a sporty two-seater roadster, offered a compelling blend of performance and style. It was available with a choice of inline-six engines, paired with either a manual or automatic transmission. While generally considered a well-built vehicle, like any car of its age, certain components can experience issues. This analysis focuses on documented common problems beyond routine maintenance, providing insights into potential reliability concerns for owners and prospective buyers. Understanding these potential pitfalls can help in proactive maintenance and budgeting for repairs.

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Engine

2.5L M54B25 Inline-6

VANOS System Failure

• Symptoms: Rough idle, loss of power, increased fuel consumption, rattling noise on startup.
• Solution: Rebuild or replace VANOS unit and seals.
• Cost: $500 - $1200

Oil Leaks (Valve Cover Gasket, Oil Pan Gasket)

• Symptoms: Visible oil drips, burning oil smell, low oil level.
• Solution: Replace leaking gaskets.
• Cost: $300 - $700

3.0L M54B30 Inline-6

VANOS System Failure

• Symptoms: Rough idle, loss of power, increased fuel consumption, rattling noise on startup.
• Solution: Rebuild or replace VANOS unit and seals.
• Cost: $500 - $1200

Oil Leaks (Valve Cover Gasket, Oil Pan Gasket)

• Symptoms: Visible oil drips, burning oil smell, low oil level.
• Solution: Replace leaking gaskets.
• Cost: $300 - $700

Transmission

5-Speed Manual

Clutch Wear

• Symptoms: Slipping clutch, difficulty shifting gears, grinding noises.
• Solution: Replace clutch kit (clutch disc, pressure plate, release bearing).
• Cost: $800 - $1500

5-Speed Automatic (GM A5S325Z)

Transmission Fluid Leaks

• Symptoms: Leaking fluid from seals or cooler lines, rough shifting, delayed engagement.
• Solution: Replace leaking seals or lines, flush and refill transmission fluid.
• Cost: $400 - $900

Torque Converter Issues

• Symptoms: Shuddering at low speeds, slipping, harsh shifts.
• Solution: Replace torque converter.
• Cost: $1000 - $2000

6-Speed Manual

Clutch Wear

• Symptoms: Slipping clutch, difficulty shifting gears, grinding noises.
• Solution: Replace clutch kit (clutch disc, pressure plate, release bearing).
• Cost: $800 - $1500

Suspension

Standard Chassis

Worn Control Arm Bushings

• Symptoms: Clunking noises over bumps, vague steering feel, uneven tire wear.
• Solution: Replace control arm bushings or entire control arm assembly.
• Cost: $400 - $800

Rear Shock Absorber Leaks/Failure

• Symptoms: Bouncy ride, reduced handling stability, visible fluid leaks from shocks.
• Solution: Replace rear shock absorbers.
• Cost: $300 - $600

Electrical

General Electrical System

Window Regulator Failure

• Symptoms: Power windows not operating, slow window movement, grinding noise from door.
• Solution: Replace window regulator motor and mechanism.
• Cost: $300 - $600

Headlight Bulb Failure (Xenon)

• Symptoms: One or both headlights not illuminating, flickering.
• Solution: Replace Xenon bulb and/or ballast.
• Cost: $200 - $500

Exterior

Convertible Top Mechanism

Hydraulic Leaks/Pump Failure

• Symptoms: Convertible top not operating, slow operation, fluid leaks under the car.
• Solution: Repair or replace hydraulic lines, pump, or cylinders.
• Cost: $800 - $2000

Body Panels

No widespread issues reported.

• Symptoms: N/A
• Solution: N/A
• Cost: Varies

Interior

General Interior

HVAC Blower Motor Failure

• Symptoms: No air coming from vents or intermittent airflow, strange noises from dashboard.
• Solution: Replace HVAC blower motor.
• Cost: $200 - $400

Seat Actuator Issues

• Symptoms: Power seats not moving or moving erratically.
• Solution: Replace faulty seat actuator motor.
• Cost: $300 - $600

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Summary Verdict

The 2004 BMW Z4, particularly with its inline-six engines, is a desirable sports car. While generally robust, common issues revolve around the VANOS system, oil leaks from gaskets, and wear on clutch components for manual transmissions. Automatic transmissions can develop leaks or torque converter problems. Suspension components like control arm bushings and rear shocks are also known to wear. Electrical gremlins can include window regulators and Xenon headlight components. The convertible top mechanism is a notable area for potential hydraulic issues. Despite these potential repairs, many Z4s remain reliable with proper maintenance, offering an engaging driving experience.