Radiator Expansion Tank BMW F20 F21 F30 F32 3 Bottle Petrol 7642158

BMW F20 F21 F30 Expansion Tank Reservoir 7642158 is an original cooling system component from the Expansion Tanks category, designed for BMW cars with gasoline engines. This used reservoir ensures a factory fit, maintaining proper cooling system operating parameters and stable fluid pressure during daily and dynamic use.

Specifications and technical data

• SKU: 7642158-3
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7642158
• Substitutable numbers: 17137642159, 7642159, 171376421587642158, 17137609469, 7609469, 17137642158, 7642158
• Fuel type: Petrol
• Category: Expansion & Overflow Tanks

Intended Use and Fitment for BMW Models

The presented expansion tank is a cooling system component dedicated to the BMW F20, F21, and F30 series with gasoline engines. Thanks to its construction compliant with the manufacturer's standards, it maintains:

• correct positioning of spigots and mounting points relative to the radiator and hoses,
• appropriate working volume for gasoline engine cooling systems,
• compatibility with factory sensors and system accessories.

Such a fitment reduces the risk of leaks, facilitates installation, and helps maintain stable engine operating temperature.

Construction and Function in the Cooling System

The expansion tank plays a crucial role in compensating for coolant volume changes and bleeding the system. The OEM construction ensures:

• a properly shaped working chamber, conducive to separating air bubbles,
• adaptation for use with the pressurized cooling system cap,
• stable mounting in the engine bay, reducing vibrations during driving.

This allows the cooling system in BMW F20, F21, and F30 series to operate within the manufacturer's specified pressure range, contributing to the longevity of the gasoline engine and its accessories.

Benefits of Using an Original Expansion Tank

Choosing an original reservoir for your BMW offers a range of practical operational benefits:

• Factory Fitment – no need for modifications to hoses or brackets, installation according to BMW service documentation.
• Parameters Compliant with Manufacturer's Design – the correct geometry and capacity of the tank support stable cooling system operation in gasoline engines.
• Seamless Integration with Existing Accessories – compatibility with intended sensors and control elements.

This solution is particularly beneficial for servicing vehicles used intensively, where the predictability of the cooling system's behavior is important.

Characteristics of a Used Product

The offered reservoir is a used part obtained from disassembly. This means it may show signs of previous use but retains the functionality required for continued operation. For many BMW users, this represents a sensible compromise between cost and maintaining the original specifications of the cooling system component.

How to Choose the Right BMW Expansion Tank

When selecting an expansion tank for BMW F20, F21, and F30 series with a gasoline engine, it is worth paying attention to:

• compliance with the body generation and engine type,
• adaptation for gasoline fuel (thermal characteristics of the system),
• retention of the factory layout of spigots and mounting points.

Choosing a component that aligns with the manufacturer's design reduces the risk of overheating, bleeding issues, and system leaks.

If you are looking for other BMW expansion tanks for similar models, check out our dedicated offer: BMW expansion tanks.

When planning more extensive chassis service or car upgrades, it is also worth consulting the guide on our blog, which discusses the selection and operation of suspension components: stock vs. sport suspension and used suspension parts.