The Short Answer
A refrigerator makes cold in the sealed system, then relies on fans and a defrost cycle to move that cold where it belongs. Most not-cooling calls are a breakdown in moving the cold, not making it. A condenser choked with dust cannot shed heat, an evaporator fan that has quit cannot circulate cold air, and an evaporator iced over by a failed defrost system blocks airflow entirely. True refrigerant loss happens but is less common.
Common Causes in Order
- Dirty condenser: the unit runs constantly and still drifts warm because it cannot release heat.
- Evaporator fan failure: cold air is made but not circulated, so the fresh-food side warms while the freezer stays cold.
- Defrost failure: the evaporator ices over until air can no longer pass, usually a defrost heater or sensor.
- Stuck air damper: the flap that meters cold air into the fresh-food compartment jams.
- Sealed-system loss: a refrigerant or compressor fault, where the system no longer makes cold at all.
Notes by Brand
The symptom looks a little different depending on what you own:
- Sub-Zero: dual refrigeration means the fresh-food and freezer sides run on separate systems, so one compartment can warm while the other holds. This often points to the fresh-food evaporator fan or defrost circuit.
- Bosch and Miele: these often surface a fault code or alarm when temperature drifts, which helps localize the problem to a sensor, fan, or defrost condition.
- Thermador, Viking, and Monogram: column and pro units frequently drift warm from a dirty condenser or a failed evaporator fan, both of which we see regularly.
- Liebherr: integrated units may show a temperature alarm; the cause is usually airflow or a sensor rather than the compressor.
| What You Notice | Likely Cause | What We Do |
|---|---|---|
| Runs nonstop, still warm | Dirty condenser | Clean condenser, verify airflow |
| Fresh-food warm, freezer cold | Evaporator fan or damper | Replace fan or damper |
| Frost on back wall | Defrost heater or sensor | Replace defrost component |
| Both sides warm | Sealed system or compressor | Diagnose and repair sealed system |
Protect Your Food First
Move perishable and valuable items to a working refrigerator or a cooler with ice, and keep the door closed to hold temperature. Do not keep opening it to check. Then pull the grille and see whether the condenser is caked with dust.
Still Warm After Cleaning the Condenser?
Book a diagnostic visit. Diagnostic and travel fees, if applicable, are confirmed before the appointment and before repair approval.
Frequently Asked Questions
Can a Refrigerator Stop Cooling but Still Run?
Yes. A fridge whose compressor and fans run can still drift warm if the condenser is dirty, an evaporator fan has failed, or the defrost system has iced over the evaporator so air cannot pass through it. The unit works hard but cannot move cold air where it is needed.
How Long Can Food Stay Safe in a Warm Fridge?
As a general guide, refrigerated food is questionable after about four hours above 40 degrees. Keep the door closed to hold temperature longer, and move the most perishable items to a working unit or cooler while you arrange a repair.
Is a Not-Cooling Refrigerator Worth Repairing?
For built-in and integrated units, usually yes, because most warm-fridge faults are a fan, defrost part, or control rather than the whole system. We diagnose the cause and give you an honest estimate before any work.