Corsair Hydro Series H115i RGB PLATINUM rattle.

Hi, i have a Corsair Hydro Series H115i RGB PLATINUM, although its doing a good job keeping my i7 7700k under control....the noise from the pump is not, my cpu temps at idle are around 30-32c on the package and fluid temps around 26c so it doing its job but on extreme setting for the pump its very loud, on balanced it gives a low pitched hum....not as loud as extreme but still irritating, but not as irritating as quiet mode....yes the hum is quieter but its give a rattling noise which is pretty loud, has anyone had this issue, could it be due to an air pocket in the main block or is it an rma job.

My previous cooler was the H110i gt(which i keep as spare) which was quieter by far but had coolant issues within the first 9 months which i ended up draining the cooler of coolant and lime scale and replacing it with fesser one clear coolant but while i didnt get scale again i had to top up the fluid at least once every 12 months.