LG Refrigerator Not Cooling: Linear Compressor and Other Causes

An LG refrigerator not cooling needs one question answered before anything else: is the compressor actually running? On LG specifically that matters more than on other brands, because the linear compressor fitted to a large number of their refrigerators has a well documented failure history.

Short version: if both compartments are warm and the compressor is silent, suspect the compressor or its control board. If the freezer is cold and only the fridge is warm, the fault is airflow: the evaporator fan or a defrost failure.

First: listen at the back

Pull the refrigerator out slightly and listen at the lower rear. A working linear compressor is very quiet, producing a soft hum rather than the obvious drone of an older reciprocating unit, so quiet does not automatically mean dead.

Put your hand near the compressor housing. Warmth means it is running. Cold and silent, with warm compartments, means it is not, and that changes the whole diagnosis.

1. Linear compressor failure

This is the fault LG is known for. Linear compressors used across many of their refrigerators from the mid 2010s onward developed a reputation for premature failure, and the issue was significant enough to become the subject of a class action settlement in the United States.

The pattern is distinctive: both compartments gradually warm over a day or two, the compressor is silent or clicks periodically, and there is no frost anywhere on the evaporator because no cooling is being produced at all.

Before assuming the worst, check your model and serial against LG’s own support resources. Some units were covered by extended warranty terms on the sealed system, and that materially changes whether repair or replacement is the right decision.

2. Failed start relay or inverter board

Before condemning a compressor, the relay and the inverter control board that drives it need testing. A failed inverter board produces exactly the same symptom as a dead compressor, and it is a dramatically cheaper repair.

Any diagnosis that jumps straight to replacing the compressor without testing the board first deserves a second opinion, because the cost difference is substantial.

3. Frost blocking the evaporator

If the freezer is cold but the fridge is warm, this is the usual explanation. The evaporator behind the freezer or fridge back panel frosts over when the defrost cycle underperforms, until the ice blocks airflow completely.

Remove the back panel and look for a wall of ice across the coil. The underlying fault will be the defrost heater, the defrost sensor or the control board. Manually defrosting restores cooling for a few days, which confirms the diagnosis without fixing it.

4. Evaporator fan failure

The evaporator fan delivers cold air into the fridge compartment. When it fails or its blade jams against ice, the freezer stays cold while the fridge warms steadily.

Listen at the back wall. Silence, grinding or rhythmic ticking all point here. Frequently the fan is simply frozen rather than broken, which leads back to the defrost system.

5. Dirty condenser coils

Free to check and worth doing first when both compartments are warm. Coils packed with dust and pet hair cannot shed heat, so the compressor runs without ever pulling temperature down.

Unplug the appliance and vacuum the coils underneath or behind the rear panel. In Denton summers this accounts for a real share of warm refrigerator calls.

6. Condenser fan failure

The condenser fan cools the compressor and coils. When it stops, the compressor overheats and cuts out on thermal overload, then restarts once cool, giving intermittent cooling that never quite holds.

7. Sensor and control board faults

Thermistors report compartment temperatures to the main board. A drifting sensor can leave the board never calling for cooling despite healthy hardware. LG displays some sensor faults as error codes, but many models show nothing, so these are diagnosed by elimination.