The washing machine makes a loud noise during the spin cycle — what's causing it?

Almost certainly this is caused by the drum tub bearings. Alternatively, though less likely, it could be a water leak onto the motor bearings.

In the second case, the noise is indeed annoying but has no impact on the machine's performance (neighbours permitting...).

If, however, the problem is with the drum bearings, the fault is far more serious. Continuing to use the machine risks the bearings breaking completely, causing the drum to collapse.

Budget models almost all have electro-welded tubs that cannot be opened. This means the bearings are essentially irreplaceable.

Higher-end models, however, allow the appliance to be inspected and the faulty components replaced.

That said, depending on the age of the appliance, you should also consider whether it is worth simply replacing it with a new one.

According to Archimede Lab data, "noise" is the fourth most reported washing machine fault at 10.6% of interventions (22,315 cases). On Miele it is the top fault at 12%, likely linked to the high spin speeds of premium models.