Why is my evaporative cooler noisy?

On coolers that use a belt, a squeal on start-up that settles down is often a belt that has stretched or glazed. A steady grinding or rumble that rises with fan speed points to worn fan or motor bearings, which get worse the longer they run. A hum or rattle from the tank area is usually the pump, especially if it's short of water or furred up with scale.

Rattling that comes and goes, worse on windy days, is often a loose louvre panel, pad frame or cover on the roof unit. Clattering or ticking in the ceiling can come from ducts expanding and contracting, a loose outlet or a winter damper flapping.

Switch the cooler off at the controller and leave it off if you hear grinding or screeching that keeps getting worse, a loud bang, a knock from something hitting the fan, or if you smell burning or hot electrics. Running a cooler on failing bearings can damage the motor and fan, and a seizing motor can overheat. With a burning smell, also switch its circuit off at the switchboard if it is safe to reach.

Most noise faults are fixed on the roof: a new belt or bearings, refitted panels, a cleaned tank and pump, or a secured duct. It's worth doing before summer, because a cooler that sounds rough at the end of one season rarely improves over winter. Tell us what the noise sounds like, when it happens and at which fan speed.