Bosch HBC84K550B/04 noisy cooling fan

[organicman]

Our microwave combination oven is noisy in use, and whilst cooling. On inspection we found that the noise is due to the cooling fan lifting slightly as it rotates, and thus striking parts of the metal surround. The fan seems to lift because the spindle on which it is mounted is rusted, and therefore the fan does not fit tight on it as designed.

The cooling fan is mounted above the oven, offset to the left, about half-way back.

We think DIY replacement (of the entire fan, or spindle only) looks feasible, once we've got the rather heavy oven out. Are we right?

Any tips on finding the replacement part?

Anyone seen same problem with Bosch oven?

After replacement, will it simply rust again in time?

 

[organicman]

On further inspection the problem (with Bosch part 494990 Motor-fan) is that the aluminium fan blade has come loose from the steel shaft which drives it round. The fan therefore rattles noisily in operation. The steel shaft and retaining disc at its lower end is rusted - perhaps that's why the bonding with the fan blade has failed.

I do not see how the fan blade was fixed or bonded to the shaft in the first place. I guess it is possible that a steel part has simply rusted away.

Anyway, we will now order and fit replacement part, and hope it does not rust like the original!