5 Reasons Why Your AC Outdoor Unit Is Making Loud Noises

July 31, 2025

Is your AC outdoor unit making loud noises out of nowhere? Don’t worry, this is one of the most common issues Gold Coast people run into with their air conditioning. Find out 5 common reasons and what you can do to fix them with us – DEEPCHILL, air conditioning services based in Gold Coast!

Worn-out or missing rubber pads

In our opinion, this is one of the most common reasons why your outdoor unit is making loud, rattling noises. Since it sits outside, it has to deal with all kinds of weather like rain, sun, wind and more.

Over time, the rubber pads (which sit underneath the unit’s base) can become hardened or cracked, or they might fall off completely, creating a gap. Or maybe, the screws holding the unit down could become loose so that when the fan runs, this causes strong vibrations and loud sounds.

The good news is you just have to replace the old rubber pads with new ones or tighten any loose screws.

Outdoor unit hasn’t been cleaned in a while

Many people clean the indoor unit of their AC but forget about the outdoor part. The outdoor unit often collects dirt and dust. 

From time to time, this buildup can affect how smoothly the system runs and you may start to hear strange, unpleasant noises from your AC. Regular cleaning helps keep everything running smoothly and quietly.

Daikin AC outdoor unit mounted on a wall bracket. If your AC outdoor unit is making loud noises, it might signal imbalance or wear in the compressor or fan. Contact an air conditioning repair Gold Coast expert to inspect and fix the issue promptly - DEEPCHILL

Improper installation leading your AC outdoor unit is making loud noises

According to HVAC Guide Guys, most of the weight in the outdoor unit is in the compressor, which is usually off to one side. That’s why it’s important that the support brackets holding the unit are secured properly on both sides.

But in some cases, the amateur technician might only bolt down one side securely and leave the other side loose, which throws the unit off balance. If the brackets aren’t reinforced well or come loose over time, your AC could start making a lot of noise, especially when the fan is spinning at high speed.

We recommend once the technician finish installing your air conditioner, make sure to check whether the brackets are firm and holding the unit evenly before doing anything else.

Fan problems in the outdoor unit

This often happens when it rains a lot. The fan blades can get wet, which dries out the oil inside and makes the motor squeak or grind. Sometimes the blades crack or spin unevenly. Loose wires can also rub against the fan while it’s running, causing unpleasant noises from your AC.

If the noise sounds like it’s coming from the fan, it’s best to check it early before it gets worse.

Something fell into the outdoor unit – unexpected reason why your AC outdoor unit is making loud noises

This is more common than you might think. Leaves, bugs or even small lizards can end up inside your outdoor unit. If the fan hits these while spinning, it can cause rattling or clicking sounds.

Most of the time, the noise will go away on its own after a few days. But if it’s bothering you, just give the unit a quick clean to remove whatever’s stuck inside.

The reasons for why your AC outdoor unit is making loud noises come from unexpected and minor problems than you think. With proper installation and regular maintenance, your AC can run quietly and smoothly for years. And if things get tricky, contact DEEPCHILL, your trusted air conditioning repair Gold Coast services ready to help you now. 

Category: AC Repairing

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