Look for the arrow

Some case fans (but not all) have an arrow showing the direction of airflow. Some fans have a small arrow on the casing that indicate the direction of airflow. Whichever way the arrow points, that’s the side that air will blow from. (Yep, it’s that easy.)

How do I know if my PC fan is intake or exhaust?

The crossbars and the wires are usually located on the back of the fan (the exhaust side). Another quick test you can use is this: if you can see the whole blade, that’s the intake side. But if you can see the fan frame holding the motor in place, you’re looking at the exhaust side (rear side).

Is CPU fan intake or exhaust?

CPU fans are designed for exhaust, as they blow the hot air away from the CPU, but some dual fan CPUs have two fans, one as intake and one as exhaust.

Which way should CPU cooler fan face?

Make sure the front of your CPU fan is facing into the back of the heatsink, so it is pushing cooler air between the blades of the HS and out to the rear. This is where the exhaust fan(s) will take over, dragging this warmer air out of the case.