Loud Click From Fridge/Freezer (Perhaps)

[bigalxyz]

For the last year or so, maybe once a day - at random - I've heard a loud click coming from my kitchen. It sounds like a switch flicking (FWIW).

I can only think that it's coming from one of my appliances:
* Dishwasher
* Washing machine
* Gas hob
* Electric oven
* Fridge/Freezer

Using the wall switches I was able to turn off the dishwasher, the washing machine, the gas hob and the electric oven - but the click kept happening, so I'm thinking now that it's probably my fridge freezer that is making the noise. It's a Neff KG525K9625, 23 years old, so it's had a pretty good run to be fair.

Does anyone know what it might be? It's very odd.

I suppose I could turn my fridge off for a day (say) - and my freezer off for another day (they have separate power supplies), and see what happens - but I'm obviously worried about food spoiling. Is there any other way to track down a noise like this?

Thank you.

 

[big-all]

is it a shared kitchen wall ??
could it be next door

 

[bigalxyz]

is it a shared kitchen wall ??
could it be next door

No - it’s definitely from my kitchen

 

[foxhole]

Fridge and freezer can safely be turned off for an hour or so . Keep doors shut.
Do you have flaps on kitchen extract ( can open or close with a snap in winds).