BMW Z4 Series E85 2.5i 2.5si Petrol N52 Bare Engine N52B25A with 79k WARRANTY

Warranty and technical condition of the part

The engine is sold with a 90-day warranty.

The power unit was tested before removal and is in full working order.

Listing details

The offer applies to a bare engine.

The engine is sold without accessories (e.g. alternator, starter motor, manifolds, injectors, turbocharger, etc.).

BMW Z4 Series E85 2.5i 2.5si Petrol N52 Bare Engine N52B25A with 79k WARRANTY is a factory power unit from the N52 family, designed for Z4 E85 models in 2.5i and 2.5si versions. It is offered as a bare engine block, which provides a solid foundation for professional repair or a complete engine swap in BMW vehicles requiring a replacement of the block and cylinder head.

Specifications and technical data

• SKU: p0421071
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 0421071
• Substitutable numbers: 11000421071, 0421071, 11000421072, 0421072
• Fuel type: Petrol
• Number of cylinders: 6
• Category: Engines
• Engine code: N52B25A
• Mileage: 59 000

Technical characteristics of the N52B25A engine

The N52B25A engine is an inline six-cylinder petrol unit, valued for its smooth operation and the refinement typical of classic BMW R6 engines. This design ensures linear power delivery, good flexibility across the entire rev range, and pleasant operating characteristics, which are particularly noticeable in the lightweight body of the BMW Z4 E85.

As a bare engine, this component serves as the core of the powertrain – a block and head assembly prepared for the transfer of ancillaries from your existing unit. This solution is cost-effective and ensures compatibility with the vehicle's factory installation.

Application in BMW Z4 E85 2.5i / 2.5si

The presented engine is intended for BMW Z4 E85 models in 2.5i and 2.5si versions, where the N52 unit is responsible for dynamic yet comfortable acceleration. Thanks to the inline-six configuration and petrol fuel system, the engine works well with both manual and automatic transmissions (depending on the vehicle's factory specification).

Replacing the engine with such a bare unit is particularly recommended in cases of severe mechanical damage to the current unit, such as seizing, block cracks, or cylinder head issues, when repairing the old engine is no longer economically justified.

Benefits of installing a used bare engine

Choosing a used N52B25A engine for the BMW Z4 E85 allows for significant cost savings compared to purchasing a complete, new unit. At the same time, you retain the ability to use your own ancillaries, which facilitates fitting it to your specific vehicle configuration.

• Possibility to transfer existing ancillaries and electronics from the previous engine.
• Better control over repair costs while maintaining original BMW specifications.
• A particularly attractive solution for severe mechanical damage to the old unit.
• Potential for further professional refurbishment according to individual workshop requirements.

Professional approach to BMW engine replacement

To minimize the risk of unexpected expenses when working with BMW units, it is worth knowing the typical design and operational issues. Before deciding on an engine repair or swap, it is advisable to check out practical tips regarding BMW units, which you can find in the article: Troublesome BMW E90 engines – a practical guide to problematic units. Although it concerns a different model, it discusses many issues common to modern BMW engines, which are useful when planning a major overhaul.

BMW engines – selecting the right components

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other components from the same group, such as additional bare engines, blocks, or cylinder heads, check out the available parts in the BMW Engines category.