Upright cabinet-type freezer model 253-26442100 in the garage periodically fills with ice at the inside bottom of the unit, and then leaks out into puddles on the floor. We live in SC, the birthplace of oppressive heat and humidity. Is the ambient temperature in the garage causing this leaking? Items in the freezer remain frozen, no other issue with the unit.

An ice build up around the top of the door aperture isn't unusual due to some cold dense air from inside will spill out when the door is opened to be replaced with humid lighter outside air that will tend to remain at the top for a while.

Being frost free doesn't exclude it from this type of ice build up as only ice formed over the evaporator during a cooling cycle will be melted by the defrost heater.

Persistent localised ice build up could be a sign of failing insulation but this will be marked by a cold spot on the outside of the cabinet.

If we have ice on the inside of the freezer it means air is being pulled into the box somewhere. The most likely place is the door seal, it sounds like you already checked it, but I would suggest that you look very close at the bottom and aides of the seal too, it could be leaking in air from there. Check the inside liner for cracks and seal them if you find any. Look at the corners of the cabinet to make sure there is not room for air to come in.

Air leaks will lead to frost, it is just hard sometimes to find where it is leaking in.

There is a drain the back of the freezer that is frozen. Your trickle of water comes from the ice that melts off of the refrigeration coils during the defrost cycle. You need to turn off the freezer, then remove the rear cover from the back wall to expose the coils. With a hair dryer, melt all of the ice. You will find a drain under the coils. Melts all of the ice in this drain so water can get out of the freezer. When this drain is clear, you can put everything back together, and your freezer should work normally.

Either the drain hose is plugged up with ice and not dripping into evaporator tray, or the defrost unit needs to be replaced.

ice on top of freezer door they came out with a fix but does not work two vent holes on bottom of door seal mthem off with silicone moisture getting in if that don't work you need to take liner off and spray foam the liner cavities

it sound like your unit has a bad sensor on it or a leak. you should never have to add refrigerant to a unit unless theres a leak then it has to be repaired firdt the recharged.

all frost free freezers have to defrost the coils. there is a drain pan or cup in the bottom .. if it overflows or it can't drain out you will get puddles check the drain hose and drain cup or pan.. also check to see if you have ice inside the bottom of you freezer that would be a plugged or freezing drain hose..call for services if only 4 months old...

feel the sides or the coils on back if it has any see if they are hot or cold

The outsides should will be warm.  This is normal because the condensor lines run thru the cabinet from about half way up the sides and over the top.  Which is why the you shouldn't have anything stacked on top of the freezer and enough room on the sides of it for air flow.  As far as the water leak, tell me exactly where you see the water and does the bottom of the freezer (inside) have a sheet of ice on it.  If there is ice there then the drain behind the bottom panel in the freezer is frozen over and will have to be thawed out.  Let me know what you find.  If you have further questions I may need the entire model # on the sticker inside the freezer.

I would check that the door gasket makes good contact with the cabinet. If it does then I would check the temp inside the cabinet. If you have large buildups of ice on the evaporator coils then I would suggest defrosting the freezer and see if that makes a difference. Hope this helps.