1988 Lincoln towncar, 98,000 miles, 5.0 V8

Try a repair kit first. The knead up epoxy sticks work about 70 ercent of the time.
Use some sandpaper to clean and rough up the area around the hole then hold finger pressure on the repair for about 4 very loooong finger tiring minutes.
If this doesn't do it. Get a small metal screw and a rubber washer and screw it into the hole. Don't overtighten. Just mash the washer down about half way.