Evaporative cooler smells or dribbles: the pre-summer checklist
Why evaporative coolers fail on the first hot day, what a pre-summer service covers, and the three things you can do yourself in October.
Heat Cool Today. Updated 20 October 2026.
Why they fail on the first hot day
An evaporative cooler sits idle from April to November with water in the tank. The water goes stale, the pump seizes, scale builds on the pads and the float valve sticks. Then the first 35-degree day arrives and the cooler blows warm air or drips through the ceiling. Nearly every breakdown in November is a service that did not happen in October.
What you can do yourself
Turn the water on at the tap if it was turned off for winter. Run the cooler on fan only for ten minutes to clear dust. Then run it on cool and check that air comes out cold within five minutes and nothing drips from the unit or the outlets. If it does both, you are probably fine for the season.
What a service covers
The tank is drained and cleaned, the pads are checked and replaced if they are clogged or crumbling, the pump and float valve are tested, the fan and belt are checked, the water distribution is checked so every pad gets wet, and the unit is run and tested. It takes about an hour on the roof.
The smell
A musty smell is stagnant water or mouldy pads. A service fixes it. To stop it coming back, run the cooler on fan only for ten minutes before you switch it off each evening so the pads dry, and have the tank drained before winter.
Book in October
Pre-summer services are booked from October. By the first hot week in November the diary is breakdowns only. Call 0421 830 037 or book a call-out online.