Wagner Tuning Audi RS4 B9/RS5 F5 Radiator Kit (WT IC)

Wagner Tuning Competition Radiator Kit – Audi RS4 B9 / RS5 F5

The Audi RS4 B9 and RS5 F5 are powered by Audi’s 2.9-litre twin-turbocharged V6, an engine that uses an indirect charge air cooling system. Instead of cooling the compressed intake air directly with outside airflow (as a traditional front-mounted intercooler would), the system circulates water through a dedicated low-temperature radiator to remove heat from the charge air coolers. The cooler the water, the cooler the intake charge – and cooler, denser air helps the engine maintain consistent performance, particularly under sustained hard driving.

This Wagner Tuning kit replaces the factory low-temperature water radiator with a higher-capacity competition unit, designed to bring coolant temperatures down more effectively and keep them there for longer.

What Makes It Different

At the heart of the upgrade is a newly developed competition racing core. Wagner Tuning have increased the internal water volume by 55% compared with the OEM unit, giving the system far more capacity to absorb and dissipate heat. The core geometry has been carefully balanced between internal and external cooling surface area, so heat transfer is maximised without choking airflow to neighbouring components such as the main engine radiator.

The radiator also features a thermally conductive anti-corrosion coating, which helps protect the core over time and preserves cooling efficiency throughout its service life.

The volume gain comes from increased core thickness, up from 25 mm to 40 mm. A slightly reduced footprint keeps the unit easy to fit and allows it to integrate neatly into the original installation space without disturbing surrounding components.

Real-World Benefits

In everyday driving, the gains will be modest – the factory cooling system copes well enough under normal conditions. The upgrade really shows its value during sustained hard use: spirited road driving, track days, or on tuned engines where heat soak becomes a limiting factor. By holding charge air temperatures lower for longer, the engine can maintain consistent power delivery without the ECU (the car’s onboard engine computer) reducing performance to protect itself from heat.

Key Benefits

• 55% greater internal water volume for improved heat absorption
• Competition-spec core designed for sustained high-load driving
• Thermally conductive anti-corrosion coating for long-term durability
• Direct replacement for the OEM low-temperature radiator
• Helps maintain consistent power on track days and tuned vehicles

Fitment

This kit is designed specifically for the Audi RS4 B9 and RS5 F5 fitted with the 2.9-litre V6 biturbo engine. To confirm compatibility with your specific vehicle, please use the vehicle lookup tool or check the Vehicle Fitment tab for full details.

Installation

Installation is carried out in place of the original low-temperature water radiator, using existing mounting points and connections. The cooling system must be properly bled after installation to remove any trapped air, as incomplete bleeding can lead to poor coolant circulation and reduced cooling performance. Fitment is best carried out by a qualified technician familiar with the RS4/RS5 cooling system layout.