Yes, you can replace a cooler gasket. Here's how to tell if it's gone.

You can replace a cooler gasket, and the signs it’s worn out are usually obvious: the lid doesn’t close with that crisp suction, you see condensation inside the lid, or the rubber feels hard, cracked, or squashed flat.

The easiest test is the dollar bill trick. Close the lid on a dollar bill and pull it out. If it slides out without any resistance, the seal is shot. Same for a flashlight — close the lid in a dark room and shine a light around the perimeter. If you see light, you’re losing cold air.

Replacing it depends on the brand. For nicer rotomolded coolers like Yeti, Pelican, and Engel, you can order a genuine replacement gasket. Older cheap coolers often don’t have a dedicated part, but you can buy adhesive-backed foam or rubber weatherstripping from a hardware store and cut it