hey guys am new to the forum recently bought an evo 8 .so this is my story bought an evo 8 rebuild rebuild the bottom end with manley rod an weisco piston changed all valves an put back together.the problem is the fan is acting weird by coming on an of really fast plus over heats on idle for like 10 to 15 minutes but when driving it works fine never really got on boost as yet because am breaking in the motor the car is run by aem .can some of u evo guys out there assist me with some ideas on what to do thanks.everything on the car is stock .

 

Are you sure the Thermostat is good?

 

Punctuation my friend...that hurts to read.

Bleed the coolant system?
Was a new water pump installed?
Any leaks?
Test the fan control module?
What temperature are you seeing in AEMPro when it is overheating?
What AFR/timing are you running at idle?

Pressure test the system and/or smoke test it.