Outdoor unit clicks: fan blade warped by afternoon heat

A Bukit Batok flat had an outdoor unit that developed a faint click on every fan rotation, worse specifically in the afternoon heat. This hillside estate gets strong, direct sun exposure on its west-facing ledges. Nothing about a warped blade announces itself until the clicking does.

By Team Snowflake | Updated 28 Jul 2026

Case summary

Midea Wall-mounted10 years oldHDBBukit Batok, Singapore

Concern: The fan motor itself looked to be failing badly, with a full and costly replacement due soon.
Found: The fan blade had warped slightly from sustained afternoon heat, clipping the housing on each rotation
Key check: Checked the fan blade's shape against the housing before assuming a motor fault
Result: The clicking stopped completely, even through the hottest afternoons, after the new blade was fitted properly. The motor stayed untouched through the repair, and so did the budget for replacing it.

What we were told

The clicking was faint in the morning, grew clearly audible by mid-afternoon, then quietened again by evening as the ledge cooled. Cooling itself never faltered during any of it. The ledge faces west and gets direct sun for several hours each afternoon.

What we checked

A click that keeps office hours is not how fan motors fail, so the afternoon pattern became our opening question. A genuine motor fault tends to click fairly consistently regardless of temperature. Clicking that tracks the hottest hours of the day usually points at a part physically changing shape with heat instead.

The fan motor itself ran smoothly throughout, with no unusual internal noise when tested in isolation.
The fan blade had a slight warp along one edge, more pronounced than the rest of the blade.
That warped edge clipped the housing audibly only once the blade had warmed and expanded further.
No wear or damage was found anywhere on the motor bearings or housing itself at all.

What we found

Years of direct afternoon sun on this west-facing ledge had gradually warped one edge of the plastic fan blade. This likely came from repeated heat cycling day after day. In cooler morning conditions the warp sat just clear of the housing. Afternoon heat expanded the blade slightly further, enough for the warped edge to clip the housing on every rotation until temperatures dropped again in the evening.

What fixed it

We replaced the warped fan blade with a new one and confirmed clearance from the housing across a full range of outdoor temperatures. We did not recommend any motor work, since the motor itself tested cleanly throughout the visit. A shade check makes sense for this ledge, since direct afternoon sun is the real driver of the warping.

Outcome

The clicking stopped completely, even through the hottest afternoons, after the new blade was fitted properly. The motor stayed untouched through the repair, and so did the budget for replacing it.

What this case teaches us

A click that worsens in the afternoon heat often means a warped blade, not the motor

A click that specifically worsens in the hottest part of the day often points at a warped fan blade, not a failing motor.
West-facing hillside ledges can push plastic fan blades to warp much faster than shaded installs.
Ask for the fan blade's shape to be checked against the housing before approving fan motor replacement.

Questions this case answers

Does a clicking outdoor unit always mean the fan motor is failing?

No. A click that keeps to certain hours is not how a motor gives up. At this Bukit Batok flat the clicking was faint in the morning, clear by mid-afternoon and quiet again by evening. Tested on its own, the motor ran smoothly with no unusual internal noise, and the bearings and housing showed no wear.

Should the fan blade be inspected before I agree to a new fan motor?

Ask for it, yes. The blade sits right where the noise is and takes seconds to inspect against the housing. Here one edge carried a slight warp that clipped the housing once the plastic had warmed and expanded. Fitting a new blade and confirming clearance across a range of outdoor temperatures ended the clicking, and the motor was left alone.

Is afternoon sun on a west-facing ledge enough to warp a fan blade?

It was here. This ledge faces west and takes direct sun for several hours each afternoon, and that repeated heat cycling had gradually pulled one edge of the plastic blade out of shape. Shaded installs do not push blades the same way. We flagged a shade check for the ledge, since the sun is what drives the warping.

Is it significant that the clicking disappears by evening?

It is the most telling part. In cooler morning air the warped edge sat just clear of the housing, so nothing touched. Afternoon heat expanded the blade slightly further, enough for that edge to catch on every rotation until temperatures dropped. A fault inside the motor would not switch itself off as the day cooled.

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