Fridge Not Cooling? 7 Common Causes (And What To Do)

A fridge that's gone warm overnight is one of the most common calls we get - and one of the most stressful for whoever opens the door first. The good news is that "not cooling" almost never means the whole fridge is dead. It usually points to one specific, identifiable fault. Here are the seven causes we see most often, roughly in order of how frequently they turn up.

1. A Dirty Condenser Coil

The condenser coil - usually at the back or underneath the fridge - releases the heat pulled out of the compartment. When it's caked in dust and pet hair, the compressor has to work harder and struggles to keep up, especially in a hot Western Sydney summer. Vacuuming the coil every six months is one of the cheapest, most effective things you can do to prevent a breakdown.

2. A Failed Evaporator Fan

This small fan circulates cold air from the evaporator coil through the fridge and freezer compartments. If it's seized, obstructed by ice, or has a worn bearing, cold air stops moving even though the compressor is still running. You'll often hear a buzzing or rattling noise, or notice the freezer is fine but the fridge section is warm.

3. A Faulty Start Relay or Capacitor

The compressor needs a jolt of extra power to start spinning. The start relay and capacitor provide that jolt. When either fails, the compressor tries to start, clicks, and gives up - often repeatedly, every few minutes. This is frequently mistaken for "the compressor is dead," but it's usually a much cheaper part to replace.

4. A Defrost System Fault

Frost-free fridges periodically melt any ice building up on the evaporator coil using a small heater on a timer. If the defrost heater, timer, or sensor fails, ice builds up until it blocks airflow entirely. This is the classic cause of "freezer's fine, fridge is warm" on modern frost-free models.

5. A Perished Door Seal

A torn or warped door gasket lets warm, humid air leak in continuously. The compressor runs almost non-stop trying to compensate, your power bill climbs, and you'll often see condensation or ice forming around the door edge. Test it with a sheet of paper - if you can pull it out easily with the door shut, the seal needs replacing.

6. Low Refrigerant From a Leak

A sealed refrigeration system doesn't use up gas over time - if it's low, there's a leak somewhere in the line. This usually shows up as a fridge that cools a little, then drifts warm again, or never quite reaches temperature. It needs proper leak detection, a repair, and a correctly weighed recharge, not just a "top-up."

7. A Failed Compressor

The least common cause on this list, but the most expensive. A genuinely failed compressor usually runs hot to the touch and hums loudly, or won't start at all. Because it's a sealed unit, it can't be repaired internally - only replaced - which is why it's worth having it properly tested rather than assumed, since points 3 and 6 above produce very similar symptoms for a fraction of the cost.