I had this exact problem with mine. I ended up twisting the motor off and putting Vaseline on my impeller after making sure it was clean. The only problem with this was that the Vaseline would eventually dry up/ burn/ solidify and cause the impeller to seize. So I went into my LFS
and got a sml bottle of silicone. I cleaned the impeller and put some silicone on it and now it is noiseless and running. Now I am going to check on it monthly to make sure it is working. I used cotton swabs to clean the impeller with some water.
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