If your Whirlpool WRT518SZFM freezer is not freezing properly, it can be frustrating, especially when you depend on it to keep food safely frozen. A freezer that runs warm can be caused by several different issues, from blocked airflow and frost buildup to failed cooling components. The good news is that many of the most common causes can be diagnosed and fixed with basic troubleshooting and a few replacement parts.

This guide walks through the most likely reasons your Whirlpool freezer is not freezing, explains how to diagnose each problem, and gives step-by-step repair instructions. It also covers several other related parts that follow a similar repair process.

Common Causes of a Whirlpool WRT518SZFM Freezer Not Freezing

1. Dirty Condenser Coils

Symptoms: The freezer is not cooling as it should, or the refrigerator section feels warm.

Why it happens: Condenser coils release heat from the refrigeration system. If they are coated in dust, pet hair, or grease, they cannot do their job efficiently, and the freezer may stop freezing properly.

Step-by-step repair:

1. Unplug the refrigerator before beginning any maintenance.

2. Locate the condenser coils, usually at the back of the unit or underneath it.

3. Use a vacuum with a brush attachment or a condenser coil brush to remove dust and debris carefully.

4. Plug the refrigerator back in and monitor the freezer temperature.

When to call a professional: If cleaning the coils does not improve freezing performance, the issue may involve the compressor or another internal cooling component.

2. Faulty Evaporator Fan

Symptoms: The freezer is not freezing, and there is little or no air movement inside.

Why it happens: The evaporator fan circulates cold air through the freezer and refrigerator compartments. If the fan motor fails or the fan becomes blocked by ice, airflow stops and cooling performance drops sharply.

Step-by-step repair:

1. Unplug the refrigerator.

2. Locate the evaporator fan inside the freezer section near the evaporator coils.

3. Check for ice buildup around the fan. If ice is present, allow the refrigerator to defrost for 24 hours.

4. If there is no ice blockage, inspect the fan blades for obstructions and test the fan motor with a multimeter for continuity.

5. If the motor is defective, replace the evaporator fan motor with the correct replacement part.

When to call a professional: If the fan assembly is difficult to access or you are unsure about testing the motor, professional service may be the better option.

3. Defective Thermostat

Symptoms: The freezer does not maintain the correct temperature, or temperatures fluctuate noticeably.

Why it happens: The thermostat controls when the refrigeration system turns on and off. If it fails, the freezer may stay too warm or may not cool at all.

Step-by-step repair:

1. Unplug the refrigerator.

2. Locate the thermostat inside the freezer section, often near the evaporator area or the control panel.

3. Use a multimeter to test the thermostat for continuity while it is set to the coldest position.

4. If it shows no continuity when it should, remove the old thermostat and install the new one.

When to call a professional: If you are not comfortable working with electrical parts or the thermostat is difficult to reach, professional help is recommended.

4. Faulty Compressor

Symptoms: The freezer is not freezing, the refrigerator section is warm, and the compressor may run constantly without cooling properly.

Why it happens: The compressor circulates refrigerant through the sealed system. If it fails, the appliance cannot cool effectively.

Step-by-step repair:

1. Unplug the refrigerator.

2. Locate the compressor at the back of the refrigerator near the bottom.

3. Check whether the compressor is warm but not excessively hot.

4. Use a multimeter to check the compressor windings for continuity.

5. If the compressor has failed, it must be replaced by a licensed technician.

When to call a professional: Compressor replacement is not a DIY repair because it involves refrigerant handling and sealed-system tools.

5. Clogged Defrost Drain

Symptoms: Excess frost buildup in the freezer or water pooling at the bottom.

Why it happens: When the defrost drain is blocked by ice or debris, melted defrost water cannot drain properly. This can lead to frost accumulation and airflow problems that affect freezing performance.

Step-by-step repair:

1. Unplug the refrigerator.

2. Locate the defrost drain at the bottom rear area of the freezer compartment.

3. Use a turkey baster, small brush, or warm water to clear any ice or debris blocking the drain.

4. Clean the drain opening thoroughly so water can flow freely again.

When to call a professional: If the drain is clogged deeper in the line or keeps freezing repeatedly, a technician may need to access the drainage system.

Additional Parts That Follow a Similar Repair Guide

Evaporator Fan Motor (Model: W10823031)

Symptoms: Poor cooling in the freezer or refrigerator due to a lack of air circulation.

Steps to replace:

1. Unplug the refrigerator.

2. Locate the evaporator fan motor inside the freezer section.

3. Remove the mounting fasteners and disconnect the electrical connector.

4. Install the new motor and reconnect the wiring.

Condenser Fan Motor (Model: W10672722)

Symptoms: Warm freezer or refrigerator sections, frost buildup, or constant running.

Steps to replace:

1. Unplug the refrigerator and remove the rear access panel.

2. Remove the screws securing the condenser fan motor and disconnect the wiring.

3. Install the new condenser fan motor and secure it in place.

Water Filter (Model: LT1000P)

Symptoms: Reduced water flow, poor-tasting water, or a filter replacement alert.

Steps to replace:

1. Locate the water filter inside the refrigerator or in the lower grille.

2. Remove the old filter and insert the new LT1000P filter.

3. Reset the filter indicator if your model uses one.

Door Seal (Model: 4827JA2001F)

Symptoms: Warm air entering the freezer, frost buildup, or poor door closure.

Steps to replace:

1. Unplug the refrigerator.

2. Pull the old gasket off the door, removing screws or clips if needed.

3. Clean the mounting surface before fitting the new seal.

4. Press the new seal firmly into place around the full perimeter.

Defrost Heater (Model: 67004122)

Symptoms: Ice buildup in the freezer or poor freezing performance.

Steps to replace:

1. Unplug the refrigerator and access the freezer compartment.

2. Locate the defrost heater and remove the screws securing it.

3. Disconnect the electrical connections and install the new heater.

4. Reassemble the freezer components and restore power.

When to Call a Professional

Many Whirlpool WRT518SZFM freezer problems can be handled at home, especially when the cause is dirty coils, a clogged drain, or a failed fan motor. However, some repairs require professional tools or training.

You should call a technician if:

• The compressor has failed

• The refrigerator has a refrigerant leak

• You have replaced common parts and the freezer still does not cool properly

• The issue involves electrical components you are not comfortable testing

Final Note

If your Whirlpool WRT518SZFM freezer is not freezing properly, common fixes such as cleaning the condenser coils, clearing the defrost drain, or replacing a faulty thermostat or fan motor can often solve the issue. Working through these steps methodically can help you pinpoint the real cause and restore proper cooling.

For more serious problems such as compressor failure or refrigerant issues, professional repair is the safest path. With the right troubleshooting approach, though, many freezing problems can be identified early and corrected before they get worse.