Marc wrote

In the past two years we had two episodes where my
2001 side-by-side Kenmore fridge - freezer worked
fine, but the fridge warmed up. Both times were fixed
by a hair dryer heating the cold air vent (blows cold air
into the fridge and what I think is a return vent (on the
lower side of the fridge) in the fridge.

Can you tell me the most common causes

It might be caused by excessive humidity in the compartments (door
seals leaking, light staying on, etc.) or poor air flow (fan slowing,
etc.). If it were caused by a defrost water drain problem, the
condition would likely return much more frequently (like weekly).

and what I can do to prevent another reoccurrence?

Difficult to say without knowing which "Kenmore SxS refrigerator"
model you have and how it was designed (they're not all the same nor
even all made by the same manufacturer).

If you post the appliances's model number off its model and serial
number tag, someone *may* be able to tell you if there is a particular
area on your fridge's design which might need some investigation. You
can find tips for locating the model and serial number tag on your
appliances in the 'Repair Parts' section of my site linked below.

Dan O.
-
Appliance411.com
http://ng.Appliance411.com/?ref411=Kenmore+fridge

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