I do not think my hub has a temp of 160F.
I don't have any C-4's powered on anymore but yes, they did run significantly hotter than the C-5s and newer.
I've always assumed the difference was related to the exact placement of the temp sensor. I came to believe the sensors were "in" the CPU and measuring the die temp. Try flipping the hub over so the air holes are facing UP to allow the heat to rise out.
Years ago I found some of these laying around and I just stuck one under the hub to raise it up off the shelf.
I didn't attach them or anything, just balanced the hub on top to give just a bit more air flow potential.
IIRC 160 isn’t out of bounds for a C4/C3
I just felt the bottom (and top) of the case. No way is it that hot, but of course, I did not feel the die. Still, I put it on its side to allow more air around it. We'll see what happens.
2X C4 here, 158f 159f. Consistant about that temp.
About a year ago, I noticed that my C3's CPU Load average increases substantially the longer the uptime, which I think may increase the temperature. I reboot the hub every two weeks and afterwards the temperature drops from 160+ down to about 130.