Radiator, CSF Triple-Pass Aluminum - E46 M3

BimmerWorld View - Unique three-pass design maximizes cooling. CSF builds an industry leading, high-quality, all aluminum drop-in radiator that exceeds OE standards, gets rid of the plastic end tanks, and improves cooling by 25-30%.

We trust CSF quality and performance in our street and track cars to provide proper cooling with an easy direct-fit install. This E46 M3 radiator is a factory replacement using all factory shrouding, clip-on hoses, and mounting points.

CSF uses new technology packed into a compact two-row design for better cooling capacity without the added weight. More efficient B-tubes have greater surface area for cooling (15% cooling capacity increase in fin technology alone) and a precision multi-louvered fin to increase heat rejection performance and surface area contact. Additionally, this CSF part has more total cooling tubes, and a three-pass flow design for maximum cooling in race environments and extreme driving conditions - an E46 M3 industry first.

These technical features all contribute to improved cooling efficiency over OE-type performance upgrades, as well as other standard "performance" aluminum tanked radiators which are nothing more than aluminum tanks on a traditional stock core.

Read more about B-Tube technology (PDF)

INSTALLATION / BLEEDING NOTE: Any radiator replacement can result in air pockets during initial installation/filling which will not allow the system to function properly. Triple-pass radiators are extremely effective but require a bit more diligence when it comes to bleeding the system. Because of the 3-pass design’s longer flow distance and vertically segmented compartments, the bleeding on these particular radiators takes more time and diligence in order to get all the air out of the system. This part of the process is critical for the triple-pass radiator to be able to function as advertised. See our tech write-up on bleeding triple-pass radiators by clicking here.

STREET NOTE: For driving in hot ambient temperatures, especially with air conditioning on, heat soak from the AC condenser can affect the last third of the radiator core. The radiator is working correctly in these conditions, but because of the location of the temperature sensor, the triple-pass configuration is not going to produce a cooler outlet temperature versus a single pass unit. Despite the factory gauge reading being elevated, temperature probe testing shows that temperatures are well within the range for safe operating (205°), even with the AC on at full blast.

Made in Indonesia in the same factory that produces CSF parts for aftermarket and car line production for several European cars. This part is a much higher level of quality than the typical Chinese factory parts. CSF's Racing & High Performance Division is able to produce a premium high performance cooling system with a level of quality and craftsmanship that is usually found in products with a much higher price point due to their economies of scale of over 600,000 units sold globally every year. All CSF radiators come with a two year warranty against defects in craftsmanship.