I have the Cryorig C7 which is set to blowing towards the CPU. However, my case has a 250mm side fan right above that blowing away from the motherboard. Will this cause a dead zone, and if so, how can I change the CPU fan direction?
You should rethink the airflow in your case. The air is needed to go towards the CPU since that air cools down the heatsink, maybe you should change the case fan to blow inwards and put a dust trap before the fan. I could help more if I could see a plan of your airflow or even picture of the setup.
The engineers built it that way on purpose. For 1 that is the way the cooler itself is designed and 2 it is to help cooling on lower end motherboards VRMs that dont have their own passive cooling.
You should rethink the airflow in your case. The air is needed to go towards the CPU since that air cools down the heatsink, maybe you should change the case fan to blow inwards and put a dust trap before the fan. I could help more if I could see a plan of your airflow or even picture of the setup.
The CPU will overheat if you change the fan in any other configuration.
I have 3 front 120mm for intake, 1 back 120mm for exhaust, and 1 side 250mm for exhaust.