Noisy fresh water pump

Hello, after my VW T25 Komet's purring water pump, the pulsing,Rattling, noisy one in my Symbol came as a bit of a shock.
Is this normal?
Also I have come across a Fiamma Expansion Tank at Just Kampers, which purports to provide a constant flow and wondered if any of you have any experience of either the noisy pump or using/fitting the Expansion Tank?
Regards
David

Try loosening the fastening screws. They should be mounted through rubber shock absorbing spacers which if too tight don't adsorb the vibrations.