Bucky's GC Radiator Fan Mod

Bucky's GC Radiator Fan Mod

Jul 10, '21
We’ve been getting many questions about the radiator fan modification to help solve over heating after we helped out Bucky Lasek and his GC build. This solution is geared toward GC models that are overheating at idle and/or low speeds on a hot day. If the car is overheating while the car is moving, then this solution will not work.

For those with a GC with an aftermarket radiator and slim fans, we suggest switching how the ECU triggers the fans to come on. Slim fans, no matter what size, do not pull as much air as the stock fans while sitting or crawling in traffic. This lack of air flow can lead to the overheating issues Bucky and other GC owners have noticed. What is needed is to fix the problem is to switch the left and right fan triggers at the ECU itself, not at the fan with jumpers.

2002-2005 16 Bit ECUs (IE 2003 WRX)
For a 2002 or newer chassis, the stock radiator fans should be in the car even with the aftermarket radiator which means that likely those cars will not have this problem. For GCs with a WRX swap, the stock fans with an aftermarket radiator won't fit, so aftermarket fans are required. One way to solve this is with a reflash of the ECU to lower the activation temperature for the primary fan and eliminate the AC component to trigger the secondary fan. This will accomplish the same end result as flipping the fan outputs.

2004-2007 32 Bit ECUs (IE 2005 STi)
With the Cobb AP on the 32 bit ECUs there is not a modification available to remove the AC requirement to turn on the secondary fan with the ECU. The solution here is manually flipping the triggers at the ECU. For these ECUs it'll require a special tool to remove the terminals you can purchase from us.

2002-2005 WRX and JDM WRX and STi

2004-2006 STi

2006-2007 WRX and 2007 STi
Tags: DIY, Radiator