BMW Z4 E85 E86 Coolant Expansion Tank Radiator Fluid Tank Petrol 7573751

BMW Z4 E85 E86 Coolant Expansion Tank Radiator Fluid Tank Petrol is an original cooling system component designed for petrol engine versions. Engineered by BMW as a factory part, it ensures proper circulation and compensation of coolant volume, which translates into stable engine operation and thermal safety of the power unit.

Specifications and technical data

• SKU: 7573751-2
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7573751
• Substitutable numbers: 7573751, 17117573751, 7514401, 17137514401
• Fuel type: Petrol
• Category: Caps

Purpose and function in the cooling system

The expansion tank in question is a component that works in conjunction with the radiator, hoses, and coolant pump in the BMW Z4 E85/E86 generation model with a petrol engine. Its task is to compensate for changes in fluid volume during engine heating and cooling, as well as to maintain the appropriate fluid level throughout the system. A properly selected tank reduces the risk of overheating, air locks, and uncontrolled leaks.

Original BMW fitment

As a part from the BMW OE group, the tank has been designed for specific mounting points and hose routing in the Z4 E85/E86 engine bay. This ensures proper fitment with brackets, connectors, and the cap, without the need for modifications or the use of additional adapters. The original connection geometry facilitates system bleeding and the maintenance of stable operating pressure.

Performance characteristics of the used component

The presented tank comes from the secondary market, which allows for an economical repair of the cooling system while maintaining factory specifications. A used OEM component is often better fitted than many aftermarket replacements, especially in terms of shape, material quality, and compatibility with original clamps and hoses. Before installation, it is recommended to perform a standard check of tightness, the condition of the connectors and the cap thread, as well as to replace the coolant in accordance with the vehicle manufacturer's recommendations.

Benefits of using an original tank

• Factory fitment for the BMW Z4 E85/E86 cooling system with a petrol engine.
• Compatibility with original hoses, mounts, and accessories.
• Ability to maintain cooling system operating parameters in accordance with the manufacturer's design.
• Reasonable repair cost through the use of secondary market parts.

Installation and maintenance recommendations

When replacing the tank, it is worth paying attention to the condition of the supply and return hoses, as well as the pressure cap. After installation, it is necessary to thoroughly bleed the cooling system and check the fluid level after the first engine warm-up cycles. A properly installed expansion tank supports a stable engine operating temperature, which is important for the durability of seals, the cylinder head, and engine accessories.

If you are planning a comprehensive repair or upgrade of the body area and trim elements in your BMW and need other components from the same group, such as covers, overlays, or additional moldings, check the available parts in the BMW Overlays category.

For drivers considering the use of secondary market components for body and accessory repairs, an article discussing the differences between used parts and aftermarket replacements may be helpful – more information can be found in the material on choosing used body parts instead of replacements.