As part of our expanding BMW product range, AIRTEC Motorsport is proud to launch our replacement uprated radiator for the E90, E92 and E93 M3 models, suitable for track or fast road use.

The Issue
During extended periods of track or even fast road use, particularly for cars with increased levels of grip, the power steering fluid’s operating temperature can climb too high to offer sufficient protection properties. As a result, the fluid breaks down, overheats and the power steering pump starts to fail. It can even cause permanent damage, if it persistently overheats.

The Solution
With huge experience in developing uprated radiators for a variety of modified track and road cars, we chose to create a power steering cooler in the existing location but with a core that’s much taller and thicker. This means capacity is increased by an incredible 260% over standard, whilst frontal area is also increased by 109% to help cool the extra capacity.

This design increases the cooling system’s capacity as well as improving its efficiency, allowing it to retain lower running temperatures compared to an original unit during prolonged or hard use. 

Designed as a direct replacement item that uses the original connections and fittings, installation is a simple process, making it a great addition to improve cooling.

TESTED 
In June 2025, we attended a two day, back-to-back test in order to collect data as part of the track testing programme for our newly developed E9x M3 cooling package; in particular the radiator and power steering cooler. For this, we used our AIRTEC Motorsport demonstrator vehicle, which is equipped with KW V3 suspension, AP Racing brakes, a semi-slick tyre set up, uprated exhaust system, sports cats, and a remap, among other modifications and driven by this season’s Time Attack driver Alan Shepherd. 

The first day would entail data logging with the standard cooler in place, before swapping over to our AIRTEC Motorsport cooler for the next day and repeating the same process. A temperature sensor was fitted inside the power steering reservoir to constantly monitor the system’s operating temperature.

Using the original power steering cooler on the first day of testing with an Ambient Temperature of 19°C, we saw the fluid temperature exceed the 130-degree mark on both sessions, which is when the car’s CH 7 11S fluid starts to break down and fail, reaching an alarming peak of 144.4°C whilst struggling to recover. 

With the AIRTEC Motorsport power steering cooler upgrade fitted in place and an Ambient Temperature of 17°C, we saw huge drops in operating temperatures, with a peak of just 72.7°C over the two sessions; a reduction of 49%. The data also showed the larger core cooler was able to recover and then maintain lower temperatures during hard use. 

Dimensions:
OEM Power Steering Cooler
Width: 475mm
Height: 60mm
Depth: 15mm
Capacity: 0.43 litres
Frontal Area: 285cm²

AIRTEC Motorsport Power Steering Cooler
Width: 456mm
Height: 131mm
Depth: 26mm
Capacity: 1.55 litres
Frontal Area: 597cm²

Fitment:
Replaces BMW part number 1711752211908

• 120i – E81/E87/E88 (N43)
• 125i – E82 (N52)
• 128i – E82/E88 (N51/N52)
• 130i – E81 (N52)
• 320i – E90/E91/E92/E93 (N43)
• 320si – E90 (N45)
• 323i – E90/E91/E92/E93 (N52)
• 325i – E90/E91/E92/E93 (N52/N53)
• 325xi – E90/E91/E92 (N52/N53)
• 328i – E90/E91/E92/E93 (N51/N52)
• 328xi – E90/E91/E92 (N51/N52)
• 330i -E90/E91/E92/E93 (N52/N53) 
• 330xi – E90/E91/E92 (N52/N53)
• X1 25iX – E84 (N52)
• X1 28iX – E84 (N52)