how can i fix the noised ariston fridge in the world, please help?

i have a large american style ariston fridge. the model is b450bvl. compact freezer at the top and large fridge at the bottom. since i bought it, it has been making a really loud noise. if i plug it out momentarily and turn it on again the noise stops for a while but comes back about 40 mins later. have got the run around from ariston because they are in italy and have received no help or suggestions. everytime someone comes into my kitchen they go... ' that piercing and rattling is annoying, what is it? pleeeeeeeeeeeeeeeese help me. my email is junelyons@gaelic.ie