Final answer:
Restrictions in capillary tubes primarily cause compressor overheating in a refrigeration system due to insufficient refrigerant flow for cooling the compressor.
Step-by-step explanation:
The problems caused by restrictions in the capillary tubes are varied. If capillary tubes in a refrigeration system are restricted, it can lead to a range of issues. One of the primary problems that can occur is compressor overheating. This happens because the restricted flow does not allow enough refrigerant to reach the compressor to cool it down, leading to excessive heat buildup. Restrictions in capillary tubes are unlikely to directly cause overcooling, undercooling, or refrigerant leaks as these issues are typically caused by other system malfunctions or deficiencies.