The "Fat Boy" is designed around a 54MM two row core. We widened the side tanks and added the purge tank as a standard feature.

This radiator uses a 28-32 Lbs. cap for high boiling temps and a purge fitting designed to direct steam from overheating out to the front of the car. (Having a visual warning in addition to a temp gauge affords the driver expanded engine safety margin.)

We have revised the Fatboy to include an aluminum crossover pipe that eliminates the coolant hose across the bottom. For some, it is a convenience, but for those using forced induction this may be just the feature required to prevent hose damage from contact with the engine drive pulleys.

For drivers with a need for external oil cooling, we have developed a compact version of our E46 M3 oil cooler that is available as an option. It is available with the standard BMW connector provision or -10 fittings.

The float tube in the expansion tank has been lengthened to mark the desired coolant level. When the coolant meets the top of the new longer tube, the level is correct.

As with all our radiators, this one is a drop in and can be used with our Hi-Po fan and clutch for added flexibility.