Is your refrigerator running, but the food inside is starting to warm up? You may notice ice buildup in the freezer, or the temperature may be too high in both compartments. A refrigerator that is not cooling properly is an urgent problem because you have limited time to prevent your food from spoiling. Below, we explain the most common causes of refrigerator cooling problems and what you can do about them.

Cleaning the condenser coils is something you can safely check and do yourself at home. However, problems involving the compressor or sealed refrigeration system require professional service. If the issue is related to these components, we provide refrigerator repair services.

Most Common Causes

Dirty Condenser Coils

Condenser coils help the refrigerator release the heat absorbed from the refrigerant.

The location of the condenser coils depends on the refrigerator model and year of manufacture. On many older models, the condenser is located underneath the appliance and can be accessed by removing the lower front grille or kick plate. On newer models, the condenser is typically located at the back of the refrigerator, behind the compressor compartment cover.

When the coils become covered with dust, pet hair, and other debris, the compressor cannot release heat efficiently. As a result, the refrigerator may run continuously but still fail to maintain a sufficiently cold temperature.

This is one of the most common and easiest-to-prevent causes of refrigerator cooling problems.

Failed Evaporator Fan

The evaporator fan circulates cold air from the evaporator coils in the freezer into the refrigerator compartment.

If this fan stops working, the freezer may remain cold while the main refrigerator compartment begins to warm up.

When you open the freezer door, you can usually hear the fan running. If you hear complete silence, the evaporator fan may be the source of the problem.

Defrost System Failure

Modern frost-free refrigerators periodically enter a defrost cycle to prevent ice from accumulating on the evaporator coils.

If the defrost heater, defrost thermostat, defrost timer, or control board fails, ice can begin to build up on the evaporator. Eventually, the ice may completely block airflow.

Parts of the freezer walls may still feel cold, but air will no longer circulate properly.

Remove the food from the freezer and inspect the rear wall. If it is covered with a thick layer of ice, there is a good chance that the defrost system has failed.

Faulty Compressor Start Relay

The start relay helps the compressor motor start properly.

When the relay fails, you may hear the classic “click — hum — click” pattern. First, the relay clicks as it activates. Then you may hear a humming or buzzing sound as the compressor attempts to start. If the compressor fails to start, the overload protector activates and shuts the system down, followed by another click.

This cycle may repeat every few minutes.

Some faulty start relays may also make a rattling sound when shaken. This can be an initial indication that the relay may be defective.

When the compressor is not running, the refrigerator cannot produce the cooling needed to maintain a safe temperature. The good news is that a start relay is usually a relatively inexpensive component and can often be replaced quickly.

Refrigerant Leak in the Sealed System

The sealed refrigeration system consists of the compressor, condenser, evaporator, and the copper or aluminum tubing that connects these components.

If a leak develops in the system, refrigerant can escape and the refrigerator's cooling performance will decrease.

This can be one of the more expensive types of refrigerator repairs because it may require locating and repairing the leak, brazing or soldering the tubing, and recharging the system with refrigerant.

On older refrigerators, replacing the appliance may sometimes be more cost-effective than repairing the sealed system.

Faulty Thermostat or Main Control Board

The temperature control thermostat tells the compressor when it needs to run.

If the thermostat fails, the compressor may not turn on at all.

In newer models with electronic controls, the main control board manages multiple refrigerator functions. A failure in the control board can cause unstable temperatures or prevent the cooling system from operating altogether.

What Can You Check Yourself First?

Clean the Condenser Coils

Unplug the refrigerator or turn off the appropriate circuit breaker.

On older models with the condenser underneath the appliance, remove the lower front grille and use a vacuum cleaner with a brush attachment or a specialized condenser coil brush to remove dust and debris from the coils.

On newer models with the condenser at the back, carefully move the refrigerator away from the wall and remove the rear compressor compartment cover to access the coils.

This simple step can resolve many refrigerator cooling problems.

Check the Temperature Settings

Make sure someone has not accidentally changed the thermostat setting.

In general, a refrigerator temperature of 37–38°F (approximately 3–4°C) and a freezer temperature of 0°F (approximately -18°C) are recommended.

On electronically controlled models, also make sure the refrigerator is not in Demo Mode or Showroom Mode.

This can be particularly relevant with some Samsung refrigerator models, where the display and interior lights may work normally even though the appliance is not cooling.

Check the Door Gaskets

Place a dollar bill between the door and the gasket, then close the door.

If you can pull the bill out very easily, the door gasket may not be creating a proper seal.

Warm air entering the refrigerator forces the compressor to work harder and can prevent the appliance from reaching the proper temperature.

Clean the door gaskets with warm, soapy water. Food residue and other debris can prevent the gasket from sealing properly.

Listen to the Compressor

With the refrigerator plugged in and the temperature set correctly, listen for sounds coming from the back of the appliance.

A normally operating compressor should produce a steady, low humming sound.

If you hear a click every few minutes followed by silence, the compressor may be attempting to start but failing. In this situation, a faulty start relay is one possible cause.

When Should You Call a Technician?

If the condenser coils are clean, the temperature settings are correct, and the door gaskets are in good condition, the problem may involve one of the refrigerator's internal components.

Replacing an evaporator fan, repairing the defrost system, replacing a start relay, and especially servicing the sealed refrigeration system require professional diagnosis and repair.

If the compressor is making clicking sounds but failing to start, do not allow it to repeatedly attempt to start. Repeated failed start attempts can potentially damage the compressor windings.

In these situations, it is safer to contact a professional refrigerator repair technician who can accurately diagnose the problem and determine the appropriate repair.