BMW 3 Series E90 320si N45 173HP Bare Engine N45B20A with 65k miles, 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.).

The BMW E90 320si N45 173HP Bare Engine Block N45B20A is a specialized, gasoline engine block from the N45 series, designed for the sporty 320si variant. This solution is for users seeking a precisely matched engine for their BMW, while retaining the characteristics of a naturally aspirated unit. A bare engine block allows for flexible transfer of ancillaries from the existing engine, which is beneficial for professional repairs and engine rebuilds.

Specifications and technical data

• SKU: 0404479
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 0404479
• Substitutable numbers: 11000404479, 0404479, 11000404480, 0404480
• Fuel type: Petrol
• Number of cylinders: 4
• Category: Engines
• Mileage: 65 000

Technical Characteristics of the N45B20A Engine

The presented engine block belongs to the Engines category and represents BMW's family of four-cylinder gasoline units. The four-cylinder design contributes to a compact build while ensuring good running smoothness and dynamics, particularly important in the 173 HP 320si version. The N45B20A unit is valued for its linear power delivery, high operating revs, and characteristics suited for more dynamic driving.

The engine as a bare block serves as a base for completion with ancillaries, allowing the mechanic or tuner to consciously select auxiliary components. This solution optimizes the repair process while maintaining the original operating characteristics of the BMW E90 320si powertrain.

Application and Selection by VIN/OEM

The N45B20A unit is dedicated to the specific configuration of the BMW 3 Series E90 in the 320si version. Therefore, when selecting, it is crucial to verify compatibility using OEM numbers and interchangeable part numbers. In workshop practice, this means the ability to precisely match the engine block to a specific car instance, considering the year of manufacture, equipment version, and fitted ancillaries.

To better understand the process of selecting used powertrains and gearboxes, it is worth familiarizing yourself with an expert guide describing the facts and myths associated with such components. Detailed discussion of selection procedures by VIN and OEM numbers can be found in the article Why Buy Used Gearboxes and Engines – Facts Instead of Myths, which helps you make an informed purchase of a used engine.

Benefits of Choosing a Bare Engine Block for BMW 320si

A bare engine block for the BMW E90 320si is particularly advantageous when the existing ancillaries are functional or have already been refurbished. This allows you to:

• maintain compatibility with the vehicle's existing systems and ancillaries,
• better control repair costs by reusing functional components,
• customize the configuration to individual requirements (e.g., for motorsport or intensive use),
• preserve the operating characteristics typical of the 320si version, without needing to adapt another unit.

Additionally, the engine's mileage allows for an assessment of its past usage and planning of potential service work, such as checking seals or verifying timing components, even before installation in the vehicle.

Condition, Origin, and Practical Installation Tips

The engine comes from the BMW offering and is classified as used, which in workshop practice means standard verification is required before installation. It is recommended to perform basic compression measurements, leak checks, and visual inspections to confirm the unit's readiness for further operation in the demanding 320si model.

During installation, pay attention to:

• correct preparation of the contact surfaces with the cylinder head and block,
• using new gaskets and bolts in key connections,
• thorough bleeding of the cooling system after assembly,
• using oil with the specification recommended for BMW N-series gasoline engines.

This approach increases the chances of trouble-free operation of the unit and reduces the risk of common faults after engine replacement.

Other BMW Engines in This Category

If you are also looking for other BMW engines for various models of this brand, it is worth checking the full offer in the dedicated category. View available BMW engines to compare specifications and select the unit best suited for your specific project or repair.