Rein EPT0155 Engine Coolant Reservoir

OE Quality Expansion Tank for Audi Cooling Systems

The Rein EPT0155 engine coolant reservoir is an OE-quality expansion tank built for Audi cooling systems that need reliable coolant expansion and recovery. It is made from virgin plastic to help resist heat-cycle cracking and maintain long-term durability in daily driving conditions.

Compatible With 2008-2012 Audi S5, 2008 Audi A5 Quattro, 2009 Audi A4 Quattro, and 2014-2016 Audi Q5 applications. This Rein EPT0155 expansion tank is a direct-fit replacement for service work on the cooling system.

• Produced from virgin plastic meeting or exceeding OE material standards
• Resists cracking and wear from repeated heat cycles to help prevent coolant loss
• Direct-fit design supports straightforward installation
• Built to strict engineering standards for material quality and dimensional accuracy
• Grey reservoir construction for OE-style appearance

Detailed Product Overview

Rein designs this engine coolant reservoir to match the fit, form, and function expected from the original expansion tank. The EPT0155 is engineered for Audi cooling system service where a cracked or aging reservoir can lead to leaks, low coolant level warnings, or unstable engine temperatures. By using virgin plastic with no regrind content, the tank is built to better withstand thermal cycling and long-term exposure underhood.

This part cross-references URO 8K0121405M for the same application. The Rein EPT0155 is a practical OE-style replacement for Audi A4 Quattro, Audi A5 Quattro, Audi S5, and Audi Q5 models listed in the fitment data.

Common Problems This Part Can Address

• Coolant loss from a cracked or leaking reservoir
• Visible plastic fatigue from repeated engine heat cycles
• Low coolant warnings caused by reservoir failure
• Cooling system service needs on aging Audi vehicles
• Fitment issues from warped or damaged OE-style tanks

Installation Notes and Tips

Verify the vehicle application before installation, especially for 2008 Audi A5 Quattro, 2009 Audi A4 Quattro, and 2008-2012 Audi S5 models. Inspect hoses, caps, and adjacent cooling components for wear before transferring the reservoir into service. Because installation hardware is not included, reuse or replace related components as needed during the repair.

Quality Assurance

Rein manufactures this expansion tank to strict material and tolerance standards for OE-style fitment and service life. The virgin-plastic construction is selected to improve durability in high-heat cooling system environments and support dependable long-term performance.