The EcoPower 30x30x10mm High Speed HV Cooling Fan is a great option to keep your ESC and motor temps in check.  
NOTE: This fan should be installed at least 5mm away from the motor to allow sufficient air flow and prevent magnet interference. 

Features:
30mm cooling fan
Ideal for ESC and motor applications
Compatible with 2S HV LiPo systems (8.75V max)
Perfect for 1/12, 1/10 and 1/8 scale platforms   
2 pin JST connector

Product Model High Speed HV Cooling Fan
Application 1/12 - 1/8 Motor & ESC     
Fan Speed 21,000 RPM
Dimensions (LxWxH) 31x31x10.5mm
Mounting Pattern     
24x24mm