An Amana refrigerator might not stay cold for a variety of different reasons, and the exact reason likely depends on the model and specifics of the unit. Two common causes for a lack of proper temperature are faulty door seals and dirty condenser coils.
A faulty door seal allows cold air to escape while permitting room-temperature air to enter the refrigerator. An Amana refrigerator with a faulty or damaged door seal likely requires adjustment of the door to ensure an intact seal or replacement of the door gasket. The gasket typically has screws that hold it in place, and removing these lets the user swap the piece for a new one. Removing the screws on the door and replacing it may also fix alignment issues that could prevent a solid seal.
A dirty condenser coil prevents an Amana refrigerator from properly removing heat from the system, and this can lead to a decrease in efficiency that translates directly into increased heat in the fridge. If the coil gets dirty enough, the refrigerator may no longer cool the interior space at all. Cleaning the condenser coil regularly by removing dust and debris that may foul the system helps to ensure continued efficient operation and helps the unit maintain proper temperature.