Percolation? Heat soak? Don't drive during summer??

yellow rose said

Interesting. Airflow does things one might not think it will do, until you find out it does.

A SBM exhaust port (and some of the SBC exhaust ports too) will have air moving out of and into the port at the same time.

I was playing with some strings flowing a cast iron head years ago and I found it. I thought I was nuts. But it happens.

So it’s interesting but not surprising that in an enclosed space the air is moving forward.

Click to expand...

Here's a mind blower: it does it in open air too! Admittedly this likely depends largely on the shroud, fan placement, and engine rpm. My fan is about halfway out of my shroud, but I'm assuming that there's some centrifugal component to the air coming across the fan which results in a downwash. That downwash splits when it hits the ground and some of it goes forward - more of it the slower I go.
On my gravel driveway I can actually watch the fan blow dust and pine needles forward if I creep along.