🏷️ Basic Information

Make:

BMW

Model:

Z4

Model Variant:

sDrive25i

Year:

2004

Chassis Code:

E85

Engine Code Group:

N52

👋 Introduction

Segment:

Premium Two-Seater Sports Roadster

Usp:

Combination of BMW's renowned driving dynamics, premium interior, and attractive roadster styling.

Key Competitors:

Porsche Boxster, Mercedes-Benz SLK, Audi TT Roadster, Honda S2000

Driving Experience:

Rear-wheel drive, balanced chassis, responsive steering, powerful inline-six engine.

Design:

Long hood, short deck, classic roadster proportions, retractable soft-top.

Manual Value Proposition:

Provides essential knowledge for owners to maintain and service their vehicle, potentially saving on dealership costs.

📋 Manual Details

Primary Coverage:

Operation, Maintenance, Service, Basic Repairs

Additional Coverage:

Troubleshooting, Diagnostics

Estimated Page Count:

Approx. 500-800 pages (typical for comprehensive service manuals of this era)

Type:

Owner's & Service/Repair Manual

Language:

English

Format:

Digital (PDF)

📖 Manual Coverage

Powertrain:

Engine (M54B25), Fuel System, Ignition System, Exhaust System, Cooling System, Lubrication System

Drivetrain:

Transmission (Manual & Automatic), Clutch, Drive Shaft, Differential, Axles

Chassis:

Suspension (Front & Rear), Steering System, Brake System (Front & Rear), Wheels & Tires

Electrical:

Battery, Charging System, Starting System, Lighting, Instrumentation, Body Electronics, Engine Control Unit (ECU), Transmission Control Unit (TCU)

Body:

Exterior Body Panels, Doors, Hood, Trunk, Convertible Top Mechanism, Interior Trim, Seats

Maintenance:

Oil Change, Filter Replacements, Fluid Checks & Top-offs, Spark Plug Replacement, Brake Pad Replacement, Battery Service

Service:

Scheduled Maintenance Tasks, Component Inspections, Diagnostics & Troubleshooting for Common Faults

Repair:

Engine Component R&R (e.g., Alternator, Starter), Suspension Component Replacement, Brake Component Replacement, Basic Electrical Component Repair

Diagnostics:

OBD-II Code Interpretation, Symptom-Based Troubleshooting Guides

Depth:

Comprehensive - Covers routine maintenance, diagnostics, and repair procedures for most major systems. Suitable for DIY enthusiasts and professional technicians.

📊 Manual Specifications

File Type:

PDF

Searchability:

Likely text-searchable (if professionally scanned/created)

Printability:

High quality, printable pages for user convenience

Binding:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Code:

M54B25

Engine Type:

Naturally Aspirated Inline 6-Cylinder

Displacement:

2494 cc (2.5 Liters)

Horsepower:

189 hp @ 6000 rpm

Torque:

230 Nm (170 lb-ft) @ 3500 rpm

Fuel Delivery:

Sequential Multi-Port Fuel Injection (MPI)

Fuel Type:

Premium Unleaded Gasoline (91+ Octane)

ECU Type:

Bosch Motronic ME9.2 or similar

🔧 Transmission

Type:

6-Speed Manual

Type:

6-Speed Steptronic Automatic

Clutch Type:

Hydraulic, Single Dry Plate (Manual Transmission)

Manual Transmission Fluid:

BMW MTF LT-2 (or equivalent GL-4/GL-5 manual transmission fluid)

Automatic Transmission Fluid:

ATF LT71141 or BMW Part No. 8322 9 407 807 (or equivalent Esso LT 71141)

📐 Dimensions

Length:

4090 mm (161.0 in)

Width:

1740 mm (68.5 in)

Height:

1300 mm (51.2 in)

Wheelbase:

2495 mm (98.2 in)

Curb Weight Manual:

Approx. 1400 kg (3086 lbs)

Curb Weight Automatic:

Approx. 1430 kg (3153 lbs)

Trunk Volume:

260 Liters (9.2 cu ft) with top up

🛡️ Safety Features

NHTSA Front Impact:

4 Stars (Driver), 5 Stars (Passenger) - Based on typical BMWs of this era

Stability Control:

Dynamic Stability Control (DSC)

Traction Control:

Automatic Stability Control and Traction (ASC+T)

Airbags:

Frontal airbags, Side airbags

Rollover Protection:

Pop-up roll bar system

💡 Technology Features

Head Unit:

BMW Business CD or Professional CD/RDS (optional Professional Navigation System available)

Audio System:

Standard 6-speaker system, optional Harman Kardon surround sound

Cruise Control:

Standard

Bluetooth:

Optional (via BMW Assist or aftermarket integration)

🔧 Maintenance

Oil Change Interval:

BMW Condition Based Service (CBS) system typically recommends every 10,000-15,000 miles or annually, whichever comes first. Consult manual for exact recommendations.

Air Filter Replacement:

Typically every 30,000 miles or as indicated by CBS.

Cabin Filter Replacement:

Typically every 15,000-30,000 miles or annually.

Spark Plug Replacement:

Typically around 60,000 miles (for iridium plugs).

Brake Fluid Change:

Every 2 years, regardless of mileage.

Engine Oil Type:

SAE 5W-30 Synthetic engine oil meeting BMW LL-01 specification.

Coolant Type:

BMW Blue Coolant (G48), a 50/50 mix with distilled water.

Brake Fluid Type:

DOT 4 (or DOT 4 LV for vehicles with DSC).

Common Problems:

Oil leaks (valve cover gasket, oil pan gasket), VANOS solenoid issues, cooling system leaks (water pump, thermostat housing), convertible top hydraulic leaks, VANOS line failures (specific to early M54 engines).

Preventative Maintenance:

Regular inspection of oil seals and gaskets, proactive replacement of cooling system components, regular fluid flushes.

📚 Vehicle History

Legacy:

BMW has a long-standing reputation for producing driver-focused sports cars, dating back to models like the 328 and 507.

Predecessor:

BMW Z3 Roadster/Coupé

Generation:

First Generation Z4 (E85/E86)

Manufacturing Plant:

Spartanburg, South Carolina, USA

Production Years For Gen1:

2002-2008

🏆 Awards & Recognition

Car And Driver Best Convertible:

Car and Driver named the Z4 a '10Best' in 2003 and 2004 for its handling and engine.

Desempeño:

Consistently praised for its driving dynamics and balanced chassis by automotive journalists.