If you are using hot air, you should be using solder paste instead of solder on a roll. Simply done, fill the hole with solder paste and put the chip in and apply heat with a 15 watt iron and then inspect it. Clean up with acetone and alcohol when you're done.

There is a metal grommet in the hole that connects to traces on both sides of the board, but you should clean up the holes before soldering in the chips. A 15 watt iron, some flux and solder wick should clean the hole throughly. A clean hole will make the solder flow evenly to both sides. Add a bit of flux to the hole and solder from the bottom pin side and not the top chip side and let gravity and capillary action pull the solder down.

In my day, 4164s used to be $35 a piece and that price did not go down until after 1994!