Labists fan

I have a Labists kit for an Rpi 4 which comes with a cooling fan. For a while now the fan makes gargling noises at start-up, for about a minute, and then settles down to a gentle snoring. I interpret the snoring as hunting between the switch-on and switch-off states. The initial gargling I believe to be caused by worn fan-bearings; so the smooth curve of Euler’s equations, leading down to the equilibrium region, are turned into a jagged descent. Any suggestions for ameliorating this?

Any suggestions for ameliorating this?

Yes and no.

The noise is worn/dirty bearings which is a physical thing. The fan is on the way out.
Some careful use of a thin oil, such as that for sewing machines (see the "Don’t"s below) will give it some additional lubrication and buy you some time to source a replacement fan.

Note, depending on the design, you may need to remove a little sticky label in order to get to where putting oil would be useful. Do it very sparingly. Too much and it risks clogging the fan when it’s cold.

Don’t use bicycle oil, too thick. Ditto anything you’d put in a car, tractor, mower, airplanes, or steam locomotive.

Don’t use WD40 or similar, it’s practically impossible to get a tiny squirt of that, it’ll go everywhere and oil spray on the fan blades will be an absolute dust magnet.

I’d say “don’t buy another of those” – if it’s only been used for the short time that the RPi4 has existed, then it shouldn’t have worn out this quickly…

Unless you’ve been using it near a window that’s left open, and you live downwind of a cement works¹ so the bearings are full of micro-grit.

¹ Great for growing certain orchids and lime loving wild-flowers, not so useful for moving parts or car paintwork.

BTW. Rick

The Daily Doug – Episode 462

Thought you might appreciate a classical composer’s view of one of your favourites

Don’t use WD40

It is not intended to lubricate such things. I have even been told that if you have to use to free-up a lock, make sure that you put some real oil in afterwards.

Thought you might appreciate a classical composer’s view

Thank you, appreciated.

It is not intended to lubricate such things.

I know, but plenty of people seem to think it’s “oil in a spray can”, and it goes everywhere…

I’ve got the Labists fan case (only because I had to buy a kit to get hold of a Pi 4B, even over a year ago). It comes with a rather crap noisy 30mm fan which I replaced after a few months. It was still noisy due to the grill over the fan, so I cut out a 30mm hole. I still wasn’t happy with the cooling performance so I cut out the entire grill (including the fan posts) and mounted a 40mm fan instead which fits nicely in the space. It’s also quieter gives and better cooling.

+1 For Druck suggestion. In my experience it’s usually better to replace the offending fan, generally a Noctua will do the job better. Also, modifying the fan mount to host a larger one, can help to achieve quieter ventilation when the original fan is really small.

generally a Noctua [fan] will do the job better

I have a 200 watt inverter, which worked fine as delivered apart from the noisy fan!

A replacement Noctua fan fixed that problem very nicely.

For the Pi 4, a geekworm fan does the job, and quietly.

Thanks to all for their advice.
I bought a little 30mm fan for £5.99. Absolutely silent.