I have the same refer that is 21 years old also, the gaskets were leaking and the fins would frost up in a couple of days. When I did the dollar bill test I found the dollar bill slipped easily pass the gasket on the latch side. I removed a total of about .050 from the black plastic latch that screws to the refer and catches the door handle. It was enough to feel resistance on the dollar bill. I have been running it for over a week now with no frost build up. In one corner the seal was ripped and lost some compression where I ran wires for a thermometer for the freezer section, I inserted some foam rubber and sealed the rip with Shoe Goo.