The i7-990x processor has two CPU coolers that Intel may provide with it, why one gets one or the other I don't know. In either case, the fan moves air through the heat sink fins by blowing or pushing air across them, rather than sucking or pulling air across them.
You can use a small piece of paper to test and verify this. A few inches across in either dimension is fine, but to small risks it being pulled into the fan or heat sink. With the PC running, bring the paper slowly closer to the fan or heat sink and see how it reacts. It should be obvious quickly which way the air is moving.
I'm not aware of any CPU cooler that is meant to have a fan mounted to pull air across the heat sink, except in the case of a few upright radiator style coolers that use two fans in a push-pull configuration.
Parsec, thanks for taking the time to respond to my question. I also corroborated your answer with a video I found one YouTube that confirmed that the fan pushes air through the radiator. As I am in the process of building the computer, I didn't have the luxury of powering up the fan to check airflow and, because the case I have has the motherboard rotated 90 degrees with the I/O connectors facing up, I wanted to make sure the processor fan was aiding upward airflow and not bucking it.