3 Ways to Keep a Cooler Drain From Leaking

Use a rubber stopper or cork from a hardware store These create a tighter seal than the original threaded plastic plug, which can vibrate loose during travel.

Seal the outside with duct tape Wrap duct tape tightly around the drain fitting as backup insurance against leaks.

Drain the water before driving when possible Ice stays cold enough for a few hours without water, and you avoid a wet trunk entirely.